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[Houston We Have a Podcast] Apollo 10
« dnia: Maj 18, 2019, 22:43 »
Apollo 10 (1)
May 17, 2019

Credits: NASA / James Blair

"Houston We Have a Podcast" is the official podcast of the NASA Johnson Space Center, the home of human spaceflight, stationed in Houston, Texas. We bring space right to you! On this podcast, you’ll learn from some of the brightest minds of America’s space agency as they discuss topics in engineering, science, technology and more. You’ll hear firsthand from astronauts what it’s like to launch atop a rocket, live in space and re-enter the Earth’s atmosphere. And you’ll listen in to the more human side of space as our guests tell stories of behind-the-scenes moments never heard before.

For Episode 92, experts take the stage at the Johnson Space Center to discuss the historic Apollo 10 mission and how the lessons learned from that time will help us achieve our goal of returning to the Moon in 2024. This episode was recorded on April 25, 2019.   

For more information check out the Apollo 10 Mission Page!


Pat Ryan: Houston, We Have a Podcast. Welcome to the official podcast of the NASA Johnson Space Center, Episode 92, Apollo 10. I’m Pat Ryan.  On this podcast we talk with scientists, and engineers, and astronauts and lots of other folks about their part in America’s space exploration program, and today we’re taking another look into NASA’s past on the occasion of the 50th anniversary of Apollo 10. When President Kennedy set a goal for America to land a man on the moon and return him safely to Earth by the end of the decade, there was less than nine years left in the 1960s, so NASA had to move efficiently.  The first manned Apollo flight didn’t happen until October of 1968, and it didn’t leave Earth orbit; when Apollo 8 circled the moon that December there was only one year left to meet the president’s challenge!  The first test of the lunar module in Earth orbit came in March 1969, and then on May 18 they launched Apollo 10, the final dress rehearsal for the moon landing, which of course came in late July. Apollo 10 showed NASA what it had done right in its effort to meet the president’s deadline, and what it needed to refine to finish the job. And it provides lessons for today’s NASA as it works under a new challenge from the administration to get back to the moon in a few short years.  That was the discussion by a select panel of experts here at the Johnson Space Center a few weeks ago, which we’ve packaged up for your enjoyment, forthwith.

To talk about that Apollo mission of 50 years ago, you’re about to hear from General Tom Stafford, the mission commander and the only surviving member of that crew. John Young and Gene Cernan walked on the moon later, on Apollos 16 and 17, respectively, while Stafford commanded the Apollo half of the Apollo-Soyuz Test Project in 1975.  He’s joined on the panel by Bernie Rosenbaum, who worked as a propulsion engineer during the Apollo era; by Lara Kearney, the deputy manager of the Gateway Program office here at JSC, they’re the folks developing a spaceport to enable future lunar surface missions and missions to Mars; and by NASA astronaut Randy Bresnik, a veteran of two spaceflights including a five-month tour of duty to the International Space Station on Expeditions 52 and 53. The panel was hosted by NASA’s Annette Hasbrook, a former flight director during the space shuttle and space station era who then served as chief of the spaceflight training office at JSC before moving into her current job as assistant manager for program integration for the Orion Program, which is developing America’s first deep space crew vehicle.  As we listen in, you’ll hear her asking the panel members to talk about what they each see as the lessons of Apollo 10. So, here we go!


Annette Hasbrook: To set us up I'd like to set the environment for the panel.  The Apollo 10 mission was a pivotal mission in the history of human spaceflight and it was the first flight of a complete crewed Apollo spacecraft to operate around the moon.  The mission objectives included a scheduled eight-hour lunar orbit of the separated lunar module and descent to about nine miles off the moon's surface before ascending for rendezvous and docking with the command and service module in about a 70-mile circular lunar orbit.  Because of the success of Apollo 10 in late May 1969 humanity landed on the moon less than two months later on July 20th, 1969.  The reason we're here today is to reflect on the lessons and legacies of the Apollo 10 mission, to take a moment to note that we all have aerospace jobs that only exist because we stand on the shoulders of the giants on this stage, and in the audience today, and to recognize how these lessons can assist our future plans to go forward to the moon and on to Mars.  But first off we need General Stafford to give us a brief synopsis of how this whole program started and what the strategies were used to make sure it funded, was funded.  General?

Tom Stafford: Alright. You can hear me all right?  Good. Well, I want to thank all the people here, the Snoopy Award winners and also the Schulz family, for what the Charles Schulz did, Snoopy and the um…we named the, in fact I was one who chose the name Snoopy and then Cernan said, yes, we'll go down and snoop around moon…but, and then naturally, Snoopy, we had to have a name of the other spacecraft so Charlie Brown was a natural.  But let me take you back to how everything got started, why did we have Apollo?

The new president we had there in 1960 election, Kennedy, you know, wanted to do new and forward-looking things, but he goes back before that to Sputnik, and the Senate Majority Leader was Lyndon Johnson from Texas, and when the Soviets orbited Sputnik he really came on hard on Eisenhower, Nixon his vice president, as we let the Soviets get way ahead of us, and so there's a big push in science and technology throughout the United States, at universities, to go you know really get with the science.  And also it started the ballistic missile race, and the Air Force had General Schriever aiding our efforts, who was a giant; he's like Sergei Korolev was to the Soviet Union at that time.  And so things were up and running but also President Johnson, then Senate Majority Leader, put through a bill calling for a National Space Council that could be activated and deactivated by the president, and the vice president would be the chairman of it.  Well, Eisenhower for some reason thought it would jeopardize his position so he never activated it, but Lyndon Johnson was a real pusher, he kept going and pushing on it.  Then he was vice president after the election, and the first thing President Kennedy did was to activate the National Space Council with Lyndon Johnson as the head of it, and it was like a fast-moving freight train down the track with Johnson there, believe me.  So then the next item that occurred was when Yuri Gagarin, on April the 12th 1961, did one orbit around the [Earth], and Johnson and Kennedy saw the great accolades of the world to the Soviet Union and Yuri Gagarin.  And then following that on May the 5th Alan Shepard did a little suborbital flight on a Redstone Mercury combination.  He went 215 miles downrange, flew over a hundred miles an hour.

Tom Stafford speaking during the Apollo 10 panel discussion Credits: NASA / James Blair

So right, within three days after that, President Kennedy went to Vice President Johnson, said Mr. Vice President, I want an answer in two and two and a half weeks, what this country can do that will put us ahead of the Soviet Union, that is very meaningful and will show accomplishments that this nation leads the world, that will put us ahead technically, economically, and challenge us.  And Lyndon Johnson was no shrinking violet; he said yes, Mr. President I'll do that.  He put together a committee that had Robert Gilruth, first director of the [Manned Spacecraft] Center, Wernher von Braun, the director at Marshall, Abe Silverstein from, the director of Ames, Max Faget, who designed our Mercury, Gemini, Apollo and the space shuttle.  This group, and so in two and a half weeks Lyndon Johnson came back to President Kennedy and said, Mr. President, looks like there’s three types of, what we determined.  Number one, there is no way we can beat the Soviet Union in a free-return trajectory around the moon—in other words a highly elliptical orbit, will go around and moon and come back, with a very little maneuvering.  And then they can say the Soviet Union has been to the moon, they flew around it, and the average person in France or Japan or China they wouldn't know the difference.  The Soviets have been to the moon; there's no way we can beat them.  And that's exactly what the Soviets started to do with their Zond program: it was a Soyuz without the orbital ball on the front on top of a Proton rocket.  Number two, we think there's only a 50/50 chance that we can equal them or maybe beat them on orbiting the moon.  But number three, if we go and land on the moon and return to the Earth, that will definitely be ahead of the Soviet Union; it'll be bigger, more expensive, and it’ll put us way ahead technically.

And right away, Kennedy thought for a couple of minutes, said “we'll do that.”  Now that took courage because the launch success out of the Cape was about 40%--in other words we had about 60% failure of our boosters.  So the next, but also he was very smart politically: that evening he called in the leaders of the Congress like Sam Rayburn, the speaker of the House, Albert Thomas, the [chairman] of Appropriations who happen to be from Houston, Carl Albert, a whip from Oklahoma, Senator Kerr from Appropriations, from Oklahoma.  He called into kingmakers so the skids were greased with those leaders, and then the next day he had the joint session of the Congress and told the Congress that before this decade is out we will land a man on the moon and safely return.  So that is what started Apollo.

So we had the goal; the next question is how do we go to the moon? Now that became a big fight between Johnson's people, well then the Manned Space Flight Center and Marshall.  The, what Dr. Gilruth wanted was this giant booster.  We've all seen the Saturn V here, weighed six and a quarter million pounds fully-loaded, but this thing would be about fourteen million pounds.  You'd, it’d go and drop off stages, land erect, and I don't know how it being so big how the people would get out, maybe rappel down  we'll have something out of there and then take off dropping stages and come back.  Von Braun had a different idea: he wanted to take two boosters, probably one and a half the size of a Saturn V, launch one launch the second, rendezvous in orbit even though nobody had done a rendezvous and then leave again dropping off stages, land erect and come back dropping off stages direct.  There was a top engineer from Langley Research Center named John Huebel and his team, they said no: the way to go is go do a lunar orbit rendezvous.  And he kept writing papers.  Fortunately, the deputy administrator of NASA, Dr. Robert Seamans, who had been the former dean of aeronautics and astronautics at MIT, was a very technical man and he understood it, that this is the way to go.  It would be faster, it would less cost, it would be safer, you'd do it quicker.  So anyway it was finally fourteen months after President Kennedy said go, in July 1962, it was decided and announced to the world the way that we will go to the moon is using a lunar orbit rendezvous.

And so, from that, that was the decision.  I was very fortunate, I joined in the second group of astronauts who came on board about two months after that.  And so we had, it was decided we needed to train the, we need to demonstrate this, so how do we demonstrate it?  So that, we started the Gemini program after the Apollo, so…and the biggest booster we had was the Titan II booster, [ICBM] it was an intercontinental ballistic missile, and it had the Mark 6 nine-megaton warheads.  I don't know if any of you know what nine megatons is, that's nine million tons of TNT, or if you put it in pounds remember nine is, ten, megatons is nine times ten to the 6 and there's 2,000 pounds to a ton so two times ten to the third, multiply it out, it had a warhead that had eighteen billion pounds of TNT.  It was a big warhead.  And so we took off the nine megaton warhead and put on an eighteen-and-a-half foot, eight-thousand pound Gemini.  And Gemini was the first spacecraft that could maneuver in orbit, could change its orbit; Mercury could only change its attitude, it had three little solid rockets in order to give it a impulse retrograde of about 320 seconds and that would bring it down.  But Gemini we could raise and lower our altitude, change planes to some extent, and do all types of maneuvers.

So we know from history now that the Gemini put us way ahead of the Soviet Union in our total sequence, and from that I was very fortunate to be assigned with Wally Schirra to demonstrate the first rendezvous in space.  But during this period of time a great team was put together.  We were very fortunate to have Dr. von Braun and about 250 of his German people from Peenemunde and he developed a great team there at Huntsville; here we had Dr. Gilruth and he brought in some great engineers like, from all over: Chris Kraft we had, so many people, like this gentleman, and, you know, to meet that goal.  It was a 70 or 80 hour work week; [in] fact 40 hours was a vacation!  [laughter]  And so we, we started like that, and but also one of the keys we brought in General Sam Phillips, he was a two-star then, but he had managed the B-52 program, and then General Schriever had recruited him and he was a program management for the Minuteman missile, was our, our, I mean he put in the ground a thousand Minuteman missiles, he started the program, and he was brilliant.  He was a fighter pilot in World War II flying P-38s, had dogfights with Messerschmitt 109s, ME-190s, lots of 88-millimeter flak around him, and he was a veteran but he had a lot of common sense.  And personality-wise we hit it off pretty good so I had a great working relationship with General Phillips.

I want to relay you the way he thought.  He told me, when you look at a problem you use common sense, but also you have to think out of the box, and a good example was the Minuteman silos, you know were sprinkled around out fields, they were unattended; you'd have a launch control center with ten silos miles apart around, and, but we had to be sure they were secure.  Boeing was the prime contractor so they had written up a plan, and they had a national security company [inaudible], to do their security, so they came up with a big book had the thing all installed; this was it, certified.  Well, you know, in software you do IV&V, independent verification and validation; well, General Phillips wanted to do an IV&V on the security of those Minuteman silos, we had a Minuteman 1.  So what did he do, did he go to another security agency another techno…he went to the Federal Bureau of Prisons and said I want the best bank robbers you have that are in your prison.  And so he got eight convicts, and he said he didn't want the ones who went into the bank with a firearm, he wanted once it broke in mechanically.  So they rounded those people up, they went out to the silo with guards, turned them loose.  Now remember, this was guaranteed, nobody can get in there.  And General Phillips told me that within 30 or 45 minutes those eight convicts were done all over that Minuteman silo [laughter], in the umbilical feed rooms down at the flame trench, the whole thing.  So that's, so they pulled them out and fixed all the deficiencies they could see and then later he sent them back in, this time it took about three and a half hours to get done in the Minuteman silo; they fixed those.  So that’s how you think out of the box, and that always left an impression on me.  And from that, for every program I was on I was always thinking out of the box, and that later as I'll explain led to color TV but, I kind of used him and Von Braun as my model, that's how you manage programs.

Annette Hasbrook: Wow, fantastic.  So, Bernie and Lara and Randy can you briefly reflect on the importance of Apollo 10 and how that impacted your lives and how you believe that impacted humanity.

Bernie Rosenbaum: Oh okay—it’s on—okay, I think as the general just mentioned here each, each one was a stage, stepping-stones on, on the previous one, and every one, every, I mean we, whoever set up those overall activities of Mercury, Gemini, and then Apollo and the various stages of those really thought the thing through because each one added to the next one, no, no one was more important than the other, they were all important in series.  So I think that's what it really does, its, it really helped get to where we did one, on Apollo 11, very quickly.

Randy "Komrade" Bresnik speaking during the Apollo 10 panel discussion Credits: NASA / James Blair

Lara Kearney: I would say, you know, building on what Bernie just said, Apollo in general just inspired humanity, right? NASA was doing what was deemed impossible, in my opinion, on behalf of the world, and it was, it was that series of missions that was successful at the end of the day.  But as you guys saw in the video, right, this mission did some really brave stuff, right, to get out there and have to change orbits, to descend, to land, to find that spacecraft that you had to rendezvous with, that was like really gutsy at the time and they were brave enough to take that challenge and, and go for it regardless of the risks so, to me that's a lot of the lesson learned that I'd like to see bring back into our culture is just that really bold, brave willingness to go do stuff that you know we haven't done before.

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Odp: [Houston We Have a Podcast] Apollo 10
« Odpowiedź #1 dnia: Maj 18, 2019, 22:44 »
Apollo 10 (2)

Lara Kearney speaking during the Apollo 10 panel discussion Credits: NASA / James Blair

Randy Bresnik: And as a test pilot as well, what Apollo 10 did and inspired me, and was inspirational, was the fact these guys were the consummate test flight.  They had, as flight test plan they needed to go execute, they needed to get all the data, bring it back so that the next step could happen which was just two months later, the moon landing.  And so, imagine, you know, General Stafford and Gene Cernan in Snoopy, they've come 250,000 miles from Earth and all of a sudden now they are nine miles away from the surface; I mean, if the moon had grass they could kind of reach their hand out the window kind of touch the blades, they were that close.  And you know, to not go down to the surface, you know, certainly is challenging but it’s that discipline of the flight test, executing the flight test plan is certainly what is, you know, really cognizant and a good reminder for, for all of us in executing our test plans.  And as a, as an aside, you know, I always thought, you know, there's all these stories and, about how test pilots push the envelope sometimes, maybe too much, and how the, when General Stafford and Geno were in Snoopy that it must have been tempting for them to maybe just go a little farther than that fifty thousand feet, and so the stories are, at least the ones that I've heard that, you know, the LEM was made too heavy so they couldn't do that or there wasn't enough fuel put on board for them to go down to the bottom and come back up, so they would not be tempted to do that so maybe General Stafford can fill us in on you know what the reality was at that point


Annette Hasbrook: So, General Stafford, during the Apollo 10 re-entry you and your crew were recognized by the Guinness Book of Records reaching the highest speed ever attained by man, so real speed demons I've been told: Mach 37.  It's the speed record that still stands today and we may not exceed it until we bring humans back from Mars, so thinking about that what was the main difference between your training and your experience in re-entry and what advice do you have for enhancing future training for our astronauts as we go to the moon and then on to Mars?

Tom Stafford: Well, on re-entry, we knew it was also a test of the heat shield even though we'd, on one of the big Saturn V unmanned tests we had tested up close to that velocity, there really wasn't any difference between the simulator and what we did.   But we entered at nighttime over the South Pacific and you know the heat is a function of the square of the velocity, and for example, Earth orbit coming in the stagnation point on the leading edge say the shell that was about 3100 degrees; well, at that speed we came in the, our heat shield was about 6400 degrees, and so it was, but we left a flame of trail and you could see it from the ground as we came across American Samoa it was so bright you could nearly read a newspaper at night.  And we landed but we pulled about seven and a half g’s for quite a while to get subcircular.  I know we're doing 36,000 feet per second, more than that, and then we were right in the middle of the fireball, you know, maneuvering to get the vectors matched to come in, right to the aim point, and we're down to 30,000 feet per second then down to 28, we saw 25,000 feet per second we knew we were coming in, we had a capture, and coming on in. So really it wasn't any different from a simulation. One of the real keys to our success was the simulation.  We had, we pioneered simulation in the space program here, starting with Mercury which is really more of a procedure change.  The first real good procedures or simulator was the Gemini program: we had a digital simulator and how we did to rendezvous, we also had a hybrid simulator up at McDonnell Aircraft and worked out that.  But again you work out backup charts and you always think how to do something better, how can you do it faster, and so I don't know how many, fifty or sixty simulations we had for re-entry, just time and time again.  And failure modes, different thrusters failing.  So it wasn’t, it wasn't any different.

Annette Hasbrook: So, training like you fly is really a key, and we should carry that on going into the future.

Tom Stafford: I was integrated with the Mission Control Center here and it worked out super.

Annette Hasbrook: Awesome.  Bernie, talk a little bit about the design challenges on a, of the Apollo 10 spacecraft and things that impacted engineering and testing and possible impacts that could have happened and what you all did thinking about that.

Bernie Rosenbaum: Well, I mean Apollo 10 was no more unique than, than all the other systems that we developed.  I worked in the reaction control group which was responsible for the attitude control and the OHMS maneuvering systems on both Gemini and Apollo, and when we first started on that the technology status was really, really low, we didn't realize how serious the problems were.  We used two propellants that were hypergolic and these propellants as soon as you, as soon as they make contact with each other they react and at ambient temperatures you get up together in less than milliseconds you have a fire.  So they was really great.  The problem, though, was—and the flame temperature of that stuff was about 5000, 5500 degrees so you had to use special materials to avoid the stuff literally melting away and we still couldn't reach those things so we used a lot of film cooling on, on the walls to keep them cool.  And the commandents—or the Gemini and command module used ablative engines which are engines that are cooled from the inside there, basically it's a fiberglass wrap that as the heat soaks into them you gas, gas leak inside which provides a cooling to the, to the inner surface.  The LEM and command module were radiation-cooled engines, and because of the high temperature requirements those were made out of molybdenum which is a fairly brittle material, and that became a real problem for us.  This, the real serious problem is these propellants, when you look at them in a vacuum environment, if you're making long pulses the propellants come in and they react immediately because there's conditi—additional propellants coming in and things lights up and you have a nice glowing chamber there in not too many seconds.  But when we're doing attitude control, particularly like if they're trying to align for stars, you want real short pulses and we have pulses down to 13 milliseconds.  And when you look at the kinetics of what's going on, the first propellants coming in it's in a vacuum so it flashes, cools, and slows down the reaction rate.  And these two propellants will never there, mix real poorly like that it forms a material called hydrazine nitrate which is something like TNT; it just accumulates in there. And we had, I can't tell you how many times we had engines blow up: you make a series of short pulses and then all at once it would just light up and the whole thing go off like shrapnel.  And solving that problem was our biggest challenge and it took us some years to do that.  And the way we ended up solving the problem was we had to put heaters, pretty good-sized heaters, on the system to keep the, to keep the propellants from getting too cold and accumulating in there.  And the other thing is we come up with a system which, basically we called it a pre cup, it was a small engine within the main engine and it was such that the fluid dynamics whenever they would, you’d first open the valves, the fluid would go directly into the small chamber in the middle which is a small rocket engine, it would start reacting and then it would, the chamber was small enough that the pressure built up and so it made a lot less of this accumulation of this explosive material and then concurrently the propellants coming around the main manifold comes out into the chamber and the thing would go ahead and light.  And so it, those two things together really solve the problem.  Here's a section drawing of the engine—I don't know if you folks can see from back there or not—but these are the two valves that brought it in and here's this little engine in the middle we called the pre cup, and that went a long way towards solving it.  But we, we had tests that, that, we were worrying about that thing shattering and so one of the things we did was I went up to LEM, to Bethpage and got a couple panels of windows and we had a program with the explosive research lab in Pittsburgh and we set these windows up around it, and here's another chamber this is the chamber we actually used for testing, just the stainless chamber, but you can see how it's all ballooned out here, this is one where we had an ignition delay in it and when it went off it just literally ballooned this out.  So we used this in, as an example of the type of energy that was stored there so we made other test chambers like this and we put in TNT on some just tissue paper in there and they tried various amounts of it on several stages to get this same type of deformation.  He said okay, that's probably a pretty good calibration of it, and then we took a real chamber like this, put the same TNT mixture inside and detonated it against the windows and the windows did not break so that gave us confidence that we, we had that problem pretty well solved.

Annette Hasbrook: That is truly amazing, and for kids who are growing up, you do get to blow things up when you're an engineer, so that's awesome.  Study hard in school. [laughter]  So, General Stafford and or Bernie, during the Apollo 10 you know we understand that the launch trajectory was so precise that we only had to have one mid-course correction so, and this was done in the time before what we call, you know, the heavy computing capabilities that we have today, the era before modern computing.  So what lessons should our Orion and Gateway teams learn from, from this for calculating trajectories as we go on to the Moon and Mars.

Tom Stafford: Well today, with our computing efforts, I think we have it down cold what we can do as far as going into Earth orbit, and then JPL has done such a fantastic job over the years on understanding the exact trajectory of the planets, what it takes to get there.  You see the New Horizons has gone past Pluto, all that, so it's, I don't think we have any problem as far as the trajectory out there.  The main thing is systems reliability and the protection from radiation.  And I got involved…one thing I'd like to bring out is, leadership starts at the top.  And like President Kennedy said, we'll go to the moon, and that was followed through, and Johnson, and Nixon finally stopped it but, it wasn't smooth all the way.  After the tragic fire we had there in January of 1967, in the Senate, led by Walter Mondale was a senior senator from Minnesota, later the vice president to Jimmy Carter, he led a big fight to kill the Apollo program.  He was going to take the money he said put it in education.  And I got my first involvement in talking with both houses: Jim Webb, who was probably our greatest administrator, sent three of us.  Wally Schirra would be the commander of the first Apollo flight after the fire—we rearranged the crews—I was a backup commander and Frank Borman was on the accident board. He sent us individually around and we talked to the chairmen of the key committees around.  I won't use the word “lobby,” I'll use the word “educate” the good elected representatives of the United States people. [laughter] But we really worked that, and of course Lyndon Johnson had a lot of horsepower, he came in and argued.  So, Mondale didn't stand a chance, but him and a small group of senators tried to kill Apollo; they were swept aside.  But that was the first thing.  And then, President Nixon started the space shuttle, and then we had Skylab come in between as a follow-on, and the, President Reagan started the space station, under his…but then President George [H.W.] Bush said on the 20th anniversary of the first lunar landing, where we had a big event at the Air and Space Museum and a barbecue at the White House South Lawn, that, after, we’ll complete the space station—had to be redesigned, but—after the turn of the century return to the moon, and he said this time to stay, and then the second decade perhaps an expedition or two to Mars.  Well, that was great except the two houses were of the opposite party and then when President Clinton came in he, right away he said, hey, that was Bush's program that's not my program, mission is dead.  So we had to, the space exploration, that's when I really got involved with a lot of volunteer work, I was asked by President Bush, Vice President Quayle, to head this study, it's called America at the Threshold, we had eleven months, I had two floors of people over in Crystal City, George Abbey was my deputy, who was a great center director here.  George is somewhere here—thank you, George—let’s give George a hand.


And we use, like in our designed the components out of the Saturn V upgraded engines, but where the Saturn V would put than 300,000 pounds to low Earth orbit and a hundred thousand pounds after translunar injection on the way to the moon, this would put 550,000 pounds to low Earth orbit with the increased engines, nearly 300,000 pounds on TLI or on out to Mars.  But as soon as Clinton came in he killed it.  So if the president isn't behind it, you're not going to go anywhere.  So for eight years exploration was absolutely zero.  In fact I talked to Dan Goldin, the administrator, and said we can't even talk about exploration.

Well, after Clinton left George W. Bush came in and after about three years—he was tied up for the first three years with conflict in Afghanistan and Iraq—so but after three plus years he set kind of the same goal as his father, not to the same funding level but we're going to go back to the moon on to Mars.  So that started, so we had about, around five years of really going for exploration.  And Mike Griffin became the administrator, Doug Cooke, who a lot of you know, was here heading exploration but there he's associate administrator, and they had a booster—not as big as what we outlined when George and I were running the Synthesis Group—it’d put around 410,000 thousand pounds to low Earth orbit; that’s still a hefty payload out there.  And then Barack Obama comes in as president and he didn't just cancel it like that, he had a study done.  The study didn't say cancel it, but it was done with some, with Obama and the Obamaites he had batted NASA around, and that got killed.  So for really eight more years, there’s sixteen years we've had zero exploration. And now President Trump has set a goal, he reactivated the space council, which is great, with Vice President Pence in charge. So, I'm not a Nostradamus to say who will win the election in 2020, but if President Trump is re-elected we'll continue on.  He set a goal for landing on the moon.  He said boots, and he doesn't mean one left boot and one right boot, that boots, he means more than one person on the moon by 2024.  So this center has its work cut out for us and we got to do the right thing, we got to think out of the box.

Let me make one more comment, too.  You know, when I was assigned Apollo 10 to be the first lunar module out there, all we’d had on Apollo 7 was a black-and-white fuzzy TV camera; we had it on 8, the first lunar orbit the George Low pushed to beat the Soviets, and 9 which is an Earth orbit with Spider and Gumdrop, the first lunar module.  So when I came off of the back up on the first Apollo flight, after October, starting mid-November, I said when are we gonna have color TV?  Well, NASA had a program that was a three, or said three or four years we will have a color TV; I said baloney.  I said a few other things that I’ll not repeat since we have a mixed audience.  [laughter]  I said we can do it, said we're better than that, we can do it a hell of a lot faster than that.  So I talked to Chris Kraft and talked to Sam, General Sam Phillips, I had a good relationship with him, said I want to really push this, said it shouldn't be that difficult.  So, we determined the videcon camera we needed was a low-light level videcon that was classified in Vietnam, so I called General Phillips: we got two of them declassified about that fast.  There was, they had five lenses in  France that had the dynamic range—I don't know why they were in France but—we got two of those, so we had that but how do you get color?  You know, the early TV sets, remember those big sets we had?  They had, they had color guns, red blue yellow, the three basic colors; we didn't have one.  And one of the groups said, hey, let's go back to the first TV set ever invented, it had a rotating color wheel of red, blue, and yellow.  So we got an old actuator about this big off a Minuteman missile driving a color wheel, so, and basically between three and a half and four months we developed this first color TV and we put it on board Apollo 10 about a week before launch, started running integrated tests with the control center, it worked good.  So we launched and then the first color TV you saw is when we exploded off the command module, came back in and docked with the lunar module to take it away from the third stage S-IVB; as we came in to dock like that you could see this thin aluminum cover on the top of the lunar module Snoopy and the resolution of that TV was so high you could see the rivets in that thing and you could see it shake as we got to soft dock, then hard dock it really shake, and then we turned around and…but see, you had to think out of the box.  So, instead of three years plus, we did it in three and a half months.  And we got to have thinking like that if we're going to get to the moon in 2024.

But one funny thing that came out…we're feeling pretty high and we were sending pictures of the Earth back and by the end of the day the Earth was slightly bigger than a basketball, and so I was thinking kind of wiseass so I said, oh say I want you to relate to the president of the British Flat Earth Society in London he's wrong—you can see here it’s a beautiful round Earth, it's round.  So we went to sleep that night, put up the windows; next morning the Earth looked smaller than a soccer ball, between a soccer ball and a grapefruit.  And they're reading up the morning news and the second article was from the—a message from the president of the British Flat Earth Society, and he said he had a message for Colonel Stafford.  He said, yes I saw a beautiful round picture of the Earth; yes the Earth is round, but it's a flat disk.

Annette Hasbrook: Aw, that’s great.  So Randy, as we prepare to go forward to the moon and on to Mars, what can the employees here at JSC do to help prepare our crews and our control centers and our infrastructure for this new mission?

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Odp: [Houston We Have a Podcast] Apollo 10
« Odpowiedź #2 dnia: Maj 18, 2019, 22:45 »
Apollo 10 (3)

Bernie Rosenbaum speaking during the Apollo 10 panel discussion Credits: NASA / James Blair

Randy Bresnik: Well certainly everybody needs to keep doing what they're doing.  The dedication, the professionalism, the attention to detail that got us finishing up the flying of the space shuttle program, completion of the assembly of the International Space Station, you know, nineteen years now of continuous human presence in space, everything we're doing is good.  Now, to make the 2024 goal happen, though, we got to take that experience and transition it because we can't keep doing business as usual.  We need to figure out ways to be more efficient and do things more quickly.  And so, you know, procurements, the building of the spacecraft, testing the spacecraft, has to be done more quickly and more efficiently, and so we need everybody's good ideas on that because you guys are the experts on those particular things and you know where the improvements can be made.  So the time for good ideas is not past, the time is now to bring those good ideas forward so we can make 2024 a reality.


Annette Hasbrook: So General, when you and Gene entered the lunar module and prepared for the undocking maneuver, what was your level of confidence that that lunar module would operate, and what was the comm between you and Mission Control like?

Tom Stafford: Oh, our confidence: 100%.  We'd been through the testing in the altitude chamber and also while it was being built in Long Island. So I didn't have any qualms at all about the thing would operate real good.  The, the only system you wonder about was a probe and drogue.  We had three little prongs, you could see it in the museum, and that was what held the, the drogue, and over on the lunar module, on the probe.  And so when you dump the pressure, well, we had a little quality control problem on the Apollo command module.  Many of you have taken engineering drawing, you look at three dimensions, and when you look where you see a hole through a thing from a different view it’ll be a dotted line; well, we had a non-propulsive vent, so when John Young turned to vent the tunnel after we were in there it wouldn't vent, so here we were hooked on, five pounds per square inch over an area about this big, the tunnel, and it held my three little probes, and we'd had a series of failures of that test, of that, of that probe, and so we're hanging on by those three little things and the lunar module started to twist a little bit.  But Mission Control said we think it should work, so okay, here we go, we undocked.  You got a little push because we had five psi over a big area.  And so the main thing was coming back in I sure hope those three little capture probes work; if not we'd have to do a spacewalk, an EVA, to get back into the command module, which would be rather a tough task, but that was the only systems problem.

Annette Hasbrook: Great, awesome.  So Lara, with the upcoming Commercial Crew flights and the first crewed flights of Orion, what lessons can we learn from our Apollo era employees on how to safely fly dynamic and daring missions?

Lara Kearney: Let's see, so I think there's probably several different aspects to that question.  I mean just from a hardware perspective, we take a lot of the lessons learned directly from Apollo: you can see the heritage in Orion's heat shield and the parachutes, in several of the systems, we certainly took a lot of lessons learned, like General Stafford said, from the Apollo 1 fire, we, we know how now to treat materials, what kind of environments are best from an oxygen and partial pressure perspective, so just technically we, we have certainly taken a lot of those lessons learned.  Culturally, again, I think it's important that we kind of start thinking a little bit more like they did.  You've heard both Komrade and General Stafford talk about things like fighter pilot, test pilot mentality, risk-taking mentality; I think we've kind of gotten away from that a little bit and need to get kind of a little more back to the edgy, edgy way of the way explorers think, the guys that climb mountains and go to the South Pole start thinking a little bit more like that.  You've heard General Stafford say several times leadership starts at the top; I can tell you from what I'm seeing we certainly have a lot of support, not only from the White House but down even to NASA Headquarters they are really blew, blowing and moving and going to try and make all of this work.  We have taken a lot of the lessons learned.  We, from a Gateway perspective, and I know landers are gonna be the same way, we are sitting on an incredibly diverse and talented workforce that can take the lessons learned from everything we have from space station, everything we have from Orion, everything we have from Commercial Crew, and be able to fold all of that into these lunar programs.  We just need to harness all of that and, and be efficient with how we go forward, so, we do have a lot of teams working on trying to help us with what I think a lot of us would consider things like bureaucracy and red tape, and we're trying to kind of push that down and see how fast we can start to move.  And again, I think that's a lesson learned from Apollo, again it's just the top-down leadership to try and make things possible for the workforce to be successful.

Tom Stafford: Let me bring up a point, say it’s kind of a counter philosophy.  Under the Obama administration, it was decided they would have Commercial Crew, and having been through such a great success we had, I have a dim view of it because it's basically, here, we'll build a spacecraft and come and look at it.  And I think the Orion is like we did Apollo, where Randy's out working with the spacecraft, and not like this.  In other words everything NASA did in Gemini and Apollo we bought from commercial companies, except we had NASA engineers like you and all of us working right there with them, where now under this commercial idea it’s different.  And if you want an interesting mathematical exercise, you know, fraction, the numerator over the denominator; go take a look at the dollars on the top, what we're paying for a launch of commercial cargo, divided by the pound, and see what it is.  And you go look at the shuttle it was, the shuttle ran about $450 million a launch, could carry 31,000 pounds, and you also had a plus, a crew of seven, over here on the side.  Just make a comparison; I think you'll find it interesting.

Annette Hasbrook: Alright.  And speaking of Gemini, Bernie, during Gemini 8 they had a yaw OHMS thruster that was fired erratically and it was believed due to a short circuit in the wiring, so what were the lessons of Gemini 8 that you applied to the reaction control system in Apollo 10 and 11 to ensure mission success.

Bernie Rosenbaum: Well, the problem on Gemini is that they switched the valves on the ground side; they went from the circuit breaker directly to the solenoid, back out of the solenoid, the ground wire going back and the switch was down there.  And somewhere in that section of wire either a hose clamp was too tight or wire was crossed, but that was apparently made, it was a conscious decision because they had a real weight problem on Gemini and they didn't want to have the extra wires in it that they had to, if they had put it on the other side it was going to take additional weight.  And that apparently was the reason why they had it that way.  And that was changed on Apollo so that was not there.

How much more time do we have, because they're just a couple points I'd like to make that…hmm, okay, just so I'd like to like to talk about two other things.

Annette Hasbrook: Okay, go ahead.

Bernie Rosenbaum: Okay.  What I want to do is, is talk about how people can empower, how you should feel empowered when you see something that's not quite right.  Take the action and don't worry about the consequence of it.  You're out there trying to solve a problem.  And I mean, like to sight an example that could have changed history.

One of the fellows, our response, our group was responsible for the pyrotechnics…igniters…and one of the fellows who had, was working in the group had worked for the Navy for a while and knew the igniters that were being used on the lunar trainer for the, for the seat ejection seats, and he was suspicious of a problem once.  So he went to Henry Pohl, who was director of our group, he went direct that same afternoon, he went to Bob Gilruth directly and they told him the problem, Bob says we are grounding the fleet until we, until Bob certifies that we have good igniters.  And I don't know how long it was grounded, because I know the crew was fussing about they wouldn't be out there training for it, but shortly after that Bob said okay, they're all okay, Neil's in one and Neil had to bail out because of a problem.  And had that had a bad igniter on it, history would've been different.  So the point is when you feel there's a problem, take action: don't wait for someone.

Another example was that, we, I got a call from somebody in the program office saying that they just saw the design change come through where they changed the bolts on the, that hold the head on the hydraulic pumps from a standard bolt to a dry lube bolt, and if you have a dry lube bolt you need to change the torque spec.  So I didn't think a whole lot about it and she said I want you to go up in Abex, it was an Abex pump that was being built for the solid, the SRB, not orbiter.  So I says well, I don't think it's a prob, we don't, we have an issue with it because we're not changing ours out but I said I will go check it out.  So I go up to Abex, went up to the chief engineer's office, told the guy why I was there, he says come on, we’ll go back we're tear, we’re building pumps right now.  And they, and they rebuild them every flight, because, after they take them out of the water.  And they, he says we’re taking them apart right now, so I, we walked back and the guy had just literally pulled the top of the pump off, he took off the part that had an insert on it; they had real heavy-duty inserts, helical type inserts, in the aluminum so that, because—and there was a big [inaudible] with real square threads on it, and the thing had, was, I could look at the thing and I said, well that thing is slightly above the surface.  And long story short, I suspected we had the thing, they'd sheared the inserts because they used the old torque to tighten bolts, and it should have used a much, much reduced torque.  So I said to the chief engineer there I said, hey, be interesting to slice that thing in half and see what it looks like inside.  So we, okay, we go down the lab we do it, cut it in half, they made a photo micrograph, I sent it to Bud Castor down here who was one of the best metallurgists that I've ever met, and he looked at it, he sent it to his buddies at Marshall, which he should have, and about two hours later I got a call from director of engineering down here and saying, what the “F” are you doing up there?  He’s saying, I just got a call from Marshall and you were there directing them to cut up, cut apart our hardware.  So he says you're gonna get some visitors tomorrow, so there was a whole team of Marshall folks come up then, and long story short, had we not found that problem we could have had pumps being built and the heads come off on the SRB and potentially lose the vehicle.  And about three months later I get a letter from Headquarters saying, hey, you know, you won a, you won an award, a Quasar award, which is an award given to, to non-quality guys who solve a serious quality problem…and it had a 10K check with it so I didn't mind that either.  But my point is when you are suspicious of something, take action; don't just think, ah, I won't worry about it, it’s somebody else's problem.

Tom Stafford: In fact this is what I get back to on this commercial, the contracts, I call them, this Commercial Crew.  In Apollo and Gemini, people like you could really make an input—bang!—that would stop it and you get to the problem and you fix it right then.  You direct the contractor, he salutes smartly; and that's not the way the Commercial Crew is set up.

Bernie Rosenbaum: It’s a big difference, yes.

Annette Hasbrook: So it's really interesting, you know, it focuses on the safety and risk leadership, so in closing I'd be interested in your thoughts, kind of what you think about how do we go forward and balance risk and knowing that the, space flight’s inherently dangerous, so just a couple comments from each of you.

Randy Bresnik: Well certainly if we learned anything from the Apollo and Gemini effort it's that they were singularly focused on the mission, that we had to get, you know, people to the moon and back safely by the end of the decade.  And, you know, think about what we're doing now, we need to take that same focus.  People can't be, you know, we've been so ensconced in our little rice bowls and our little projects and our little teams that we're working in and focus on those; we need to be thinking about what requirements we have on the books that maybe don't apply or need to be modified and updated, and challenge those old assumptions.  We also need to be able to, you know, look at risk by swimming outside our swim lanes, you know, get outside of your tunnel vision on your particular project, know what's going on to the left and right and think like the, the decision-makers ahead of you, so that all of us can be systems integrators rather than just the folks whose jobs are systems integration.  And then lastly, you know, I think we have to make smart risk decisions and, and not just take risk because we're going someplace new but the fact that we are living and breathing the mission every day and that we feel that sense of urgency and we're only taking the risk that we have to take, and so if you're not going home every day feeling like, boy, I put in a full effort to try and, you know, not leave anything on the table or decisions that need to be made or work that needs to be done, that's what we need that.  And, and when Apollo and Gemini, you know, program happened and we went to the moon, they didn't know that they could do it; we thought we could, but we didn't know that it could be done until we actually did it.  We know it can be done now, so that'll, should allow us to harness all this incredible, you know, innovation and experience that we have to be able to go ahead and make this effort happen in just the five short years that we've got to show that we can do it.

Annette Hasbrook: Well let's give a big round of applause to our panelists, really fantastic conversation today.


Pat Ryan: Pretty interesting discussion there; thanks for hanging in.  You can check out for more information about the Apollo 10 mission, and we hope that when you do you won’t be able not to notice much more stuff about the upcoming 50th anniversary of Apollo 11, the first landing of human beings on the moon.  And to that end, we’ve gathered our own podcast episodes on all the Apollo topics in one spot, on our page at, where you can scroll down to Houston We Have a Podcast and click on the link to Apollo episodes—that leads to our Heroes Behind the Heroes series, to episodes on the science and history of the Apollo program, on the Apollo 1 fire and the Apollo 8 mission that circled the moon, and more links to many more things Apollo. You can go online to keep up with all things NASA, at It would also be good for you to follow us on Facebook, Twitter, and Instagram…you will thank me.  When you go to those sites, use the hashtag #askNASA to submit a question or suggest a topic for us; please indicate that it’s for Houston, We Have a Podcast.  When you go to, you should check out the other cool NASA podcasts that are there, like Welcome to the Rocket Ranch, and JPL’s On a Mission, NASA in Silicon Valley—they’re all available at the same spot where you can find us, This Apollo 10 panel was recorded on April 25, 2019; thanks to Alex Perryman and the Staging and Presentations crew at JSC for their help in getting the recording, to Gary Jordan and Norah Moran for their part in the production, and to the Apollo 10 panel members: Tom Stafford, Bernie Rosenbaum, Lara Kearney, Randy Bresnik and Annette Hasbrook.  We’ll be back next week.


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Odp: [Houston We Have a Podcast] Apollo 10
« Odpowiedź #3 dnia: Maj 19, 2019, 16:29 »
To 'Simply' Land: Remembering Apollo 10, 50 Years On (Part 1)
By Ben Evans, on May 19th, 2019 [AS]

Over the years, many have questioned the need for Apollo 10 and why it could not be retasked to perform a lunar landing. In reality, the mission was critical in clearing up many unknowns before a landing could go ahead. Photo Credit: NASA

Five decades ago, this week, Americans could almost taste the Moon, as the days drew closer to landing a human on its dusty surface and honoring a national pledge from the late President John F. Kennedy. Already, in December 1968—on only the second manned flight of the Apollo spacecraft—U.S. astronauts had triumphantly voyaged to lunar orbit and in May 1969 efforts were well underway to test the Command and Service Module (CSM) and Lunar Module (LM) around the Moon for the first time.

Apollo 10, crewed by Commander Tom Stafford, Command Module Pilot (CMP) John Young and Lunar Module Pilot (LMP) Gene Cernan, would be nothing less than a full dress rehearsal for the first manned landing on another world. And aboard their LM, Stafford and Cernan would approach the lunar surface and draw as close as nine miles (15 km). By the time Apollo 10 returned to Earth, a significant hurdle in enabling American boots on the Moon was gone.

Commanded by Tom Stafford (center), the Apollo 10 crew included future Moonwalkers John Young (right) and Gene Cernan (left). Photo Credit: NASA

Over the years, questions have been raised, and raised again, as to why Apollo 10 could not simply have been changed to a full-blown lunar landing. The word to stress here is “simply”; for taking such an audacious step was by no means simple. Early in 1969, NASA associate administrator George Mueller hinted strongly that Apollo 10 might land on the Moon, but Tom Stafford was decidedly unhappy about the prospect. “Tom was not so adamant about being first on the Moon,” wrote Cernan in his autobiography, The Last Man on the Moon. “He never looked at it that way. He wanted to do what was the best thing to do and have a co-ordinated, planned program.” Rather than endorsing Mueller’s suggestion, Stafford replied that if Apollo 10 was rescoped to do a lunar landing, then he—Stafford—would most certainly not be aboard the mission! There were simply too many unknowns, and too much work still to be done, before the final step could be taken.

The main problem was that LM-4, the lunar module assigned to Apollo 10, was overweight; it had always been earmarked for either an Earth-orbital or lunar-orbital test flight and as such had not been subjected to the Super Weight Improvement Program by prime contractor Grumman. However, the LM-5 lunar module was light enough to handle a landing, but to use it on Apollo 10 would necessitate a couple months’ delay. “When you added up what we would gain, as opposed to what we would lose,” explained Deke Slayton in his memoir, Deke, co-authored with spaceflight historian Michael Cassutt, “the decision was pretty easy.”

Six weeks before launch, Gene Cernan (left) and Tom Stafford stand side by side at the controls of the lunar module simulator. Their mission into the unknown would bring humanity closer to the Moon than had ever been achieved in history…until the landing itself on Apollo 11. Photo Credit: NASA

Stafford, Young and Cernan were assigned to Apollo 10 in November 1968, after wrapping up backup duties on the Apollo 7 crew, and NASA initially described their mission as encompassing a range of options, “from Earth-orbital operations to a lunar-orbit flight”. When Apollo 8 successfully circumnavigated the Moon, planning for Apollo 10 similarly expanded from a simple undocking and formation-flying exercise between the CSM/LM combo to a more detailed battery of tests, reaching just nine miles (15 km) from the lunar surface, to rehearse the point at which a real landing mission would begin its Powered Descent. This would permit an all-up test of the LM’s throttleable descent engine, landing radar and rendezvous radar. Trajectory analyst Bill Tindall even proposed a “fire-in-the-hole” burn of the LM’s ascent engine at low altitude to simulate an abort. However, on this point he was overruled, as Apollo 10 was becoming steadily overloaded with tasks.

Even in the late spring of 1969, riding on the coattails of Apollo 8’s success, many wondered why Stafford, Young and Cernan could simply not take a chance: After traveling all the way to the Moon, with all the necessary hardware in place, why not land? However, others cautioned that the software and procedures needed as the LM descended in a precise, sweeping arc, under the thrust of its throttleable descent engine, had still to be verified. Two years earlier, managers decreed that half a dozen different docking modes had to be demonstrated, ahead of a landing. “So far,” wrote Deke Slayton, “we had demonstrated exactly one.” The drive to reach the Moon was already proceeding at break-neck pace and to skip another step and attempt a landing so soon was too rash to risk.

It was no understatement that Charlie Brown and Snoopy were everywhere in the days leading up to (and during) the Apollo 10 mission. Here Snoopy, clad in bubble helmet and trademark scarf, sits with Charlie on a console in Mission Control. Photo Credit: NASA

One of the lessons carried over from Apollo 9 was the need to impose individual callsigns on the CSM and LM. The choice of “Gumdrop” and “Spider” by the Apollo 9 crew went down like a lead balloon with some NASA managers, until Stafford’s men revealed their selection: “Charlie Brown” for the CSM and “Snoopy” for the LM! It was not just a bit of fun. For years, NASA had awarded “Snoopy pins” to its staff in recognition of their outstanding work. “The choice of Snoopy was a way of acknowledging the contributions of the hundreds of thousands of people who got us there,” wrote Tom Stafford in his autobiography, We Have Capture. “Once you had Snoopy, Charlie Brown couldn’t be far away.”

Originally scheduled to fly on 1 May 1969, Apollo 10 slipped until the 17th in order to best “fit” the lunar launch window. Another 24-hour delay was effected to allow Stafford and Cernan to benefit from closer levels of sunlight to those Apollo 11 would encounter when they made their low pass over Site 2, the area on the Moon’s Sea of Tranquility where the first planning landing was slated to occur. The mission would also make history as the Saturn V’s first, and only, liftoff from Pad 39B.

Apollo 10 was the first, and only, occasion that a Saturn V launched from Pad 39B. In fact, this mission marked the first use of the complex which is now being readied for NASA’s next super-heavylift rocket, the Space Launch System (SLS). Photo Credit: NASA

Training of the prime crew and their backups—Commander Gordo Cooper, CMP Donn Eisele and LMP Ed Mitchell—was feverish as launch neared. Not until he was placed into pre-flight quarantine, in early May, could Stafford finally appreciate the enormity of the mission he was about to undertake. On the evening of the 16th, the crews had dinner with Vice President Ted Agnew and James McDonnell, founder of the aerospace giant which had built NASA’s Mercury and Gemini spacecraft. Late on the following afternoon, driving a little too fast back to the Cape Kennedy crew quarters after seeing his family, Cernan was pulled over by a deputy sheriff.

An absence of papers in his car’s glovebox, an iffy-looking military driving licence which, it seemed, never expired and an unlikely-sounding name aroused the officer’s suspicions. Fortunately, a timely intervention by launch pad leader Guenter Wendt saved the day. Sharing a quiet “word” with the disbelieving cop, Wendt finally satisfied him that all was well. No, said Wendt, unfortunately “Mr. Kurnin” could not accompany the officer to the police station, because—motioning toward the distant Saturn V—he had somewhere important to go tomorrow.


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Odp: [Houston We Have a Podcast] Apollo 10
« Odpowiedź #4 dnia: Maj 29, 2019, 11:46 »
“We Didn’t Know the Questions”: Remembering Apollo 10, 50 Years On (Part 2)
By Ben Evans, on May 26th, 2019 [AS]

Tom Stafford pats an enormous stuffed Snoopy as he leads his crew out of the Operations & Checkout Building at Cape Kennedy for the Apollo 10 launch on 18 May 1969. Photo Credit: NASA

Snoopy, the little black-and-white dog from the Peanuts comic strip, was everywhere at NASA five decades ago, this month, as Apollo 10 and its three-man crew—Commander Tom Stafford, Command Module Pilot (CMP) John Young and Lunar Module Pilot (LMP) Gene Cernan—prepared for their launch to the Moon. Snoopy had become the mascot for a mission which would clear the final hurdle in accomplishing humanity’s first piloted landing on the surface of another world. As outlined in last weekend’s AmericaSpace history feature, Apollo 10 was already shaping up to be one of the most complex missions ever attempted.

At Cape Kennedy in Florida, he could be seen wearing his red scarf and astronaut’s bubble helmet on sweatshirts, stickers, posters and buttons. In fact, there were some uncanny parallels with Jules Verne’s famous 1865 novel about a journey to the Moon, which also launched from Florida, also carried three men and also included a canine passenger. Yet the trials that Apollo 10 would face greatly dwarfed anything even the mind of Verne could possibly have conceived. On the morning of 18 May 1969, the risk was temporarily set aside in the excitement. Walking down the hall of the Operations and Checkout Building, Stafford spotted one of their crew secretaries, Jamie Flowers, holding an enormous stuffed Snoopy. Stafford patted it on the head, Young swiped at it and Cernan playfully tried to grab it and take it with him.

The playfulness ended when they arrived on the gantry of Pad 39B and were overwhelmed by the seriousness of what was about to happen. “The elevator door rattled closed as we rose up,” wrote Cernan in his autobiography, The Last Man on the Moon, “higher and higher and we could see clearly through the wide openings of the safety door. Every inch of the way the rocket beside us hummed and vibrated. Glass-like chunks of ice slid away as her cryogenic lifeblood…boiled and bubbled in her guts. She’s alive!” At length, the elevator stopped and technicians welcomed them to the “Twelve-Forty-Nine Express,” in light-hearted reference to their scheduled 12:49 p.m. EDT liftoff time.

In the distance, on the beaches and roadways of the Cape, hundreds of cars and trucks and camper vans sat bumper-to-bumper. Thousands of spectators primed themselves for the event of 1969 which only one other mission could possibly surpass: the landing itself in July. It was a few minutes after 10 a.m. that Tom Stafford entered the command module, which the crew had dubbed “Charlie Brown”, and scrunched himself into the commander’s seat on the left side of the cabin. Next, Cernan assumed the right-side seat of the LMP and, lastly, came John Young in the center seat as the CMP. Pad leader Guenter Wendt—who had saved Cernan from an unfortunate episode with a deputy sheriff the day before, as outlined in last weekend’s AmericaSpace history article—wished them good luck, tapped their helmets and displayed a thumbs-up, before Charlie Brown’s hatch was closed and sealed. Stafford, Young, and Cernan would see no other human being for the next eight days.

Alone now, the men broke out their checklists and began reading data to flight controllers and implementing computer updates. Apollo 10’s stabilization and control system was checked, telemetry and radio frequencies were verified, pyrotechnics were armed, internal batteries inspected, the altimeter was updated, and Charlie Brown’s reaction control thrusters were pressurised. “No time to think,” Cernan later wrote, “just time to do.” As launch neared, external power sources were removed and Apollo 10 was transferred onto its internal fuel cells. Stafford’s hand controllers were activated and the Saturn V’s guidance system assumed control.

Nine seconds before liftoff, the astronauts felt, then heard, the fuel valves opening on the giant rocket’s S-IC first stage. Then, the five mighty F-1 engines, engorged with propellant, roared to life. Three miles (5 km) away, the launch commentator counted down the final seconds, amidst a steadily increasing din: “Ignition sequence start…five, four, three, two…all engines running…” Finally, as the Saturn V broke its shackles to Earth and ponderously rose, like Prometheus unchained, came “Launch Commit…Liftoff…We have a liftoff, at forty-nine minutes past the hour!”

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CBS News coverage of the Apollo 10 launch, 50 years ago, this week. Video Credit: CBS News/YouTube

Queen Fabiola of Belgium was in the VIP bleachers and instinctively grabbed the arm of her husband, King Baudouin, in surprise as the “unearthly howl” of the largest and most powerful rocket ever brought to operational status rolled over them. Even King Hussein of Jordan, who had seen many launches, flinched at the spectacle. Inside the rattling command module, Stafford, Young, and Cernan were buffeted by vibrations which rifled their way, vertically, up through the booster.

Years later, Cernan could think of only two words to describe the sensation: “Absolutely scary.” That scariness was balanced by the pure, adrenaline-fed thrill as the Saturn climbed in stately fashion toward the heavens, taking 11 seconds to clear the tower. The ride on the first stage was a smooth, guttural roar, which pitched and rolled them out over the Atlantic Ocean for the first two minutes of the mission.

Atop a tongue of flame, and issuing an “unearthly howl”, the largest and most powerful rocket ever brought to operational status leaves Pad 39B. Said one journalist, the Saturn was “the mechanised triumph of the modern world…our pyramid of the 20th century”. Photo Credit: NASA

Next came the sharp jolt of the S-II second stage, which almost propelled them head-first into Charlie Brown’s instrument panel, and then the first worrisome signs of “pogo” arose. Pogo was an intense, low-frequency longitudinal oscillation, which rippled up through the body of the Saturn, causing it to “bounce” violently, like a giant pogo stick. “The engineers had shaved 20,000 pounds of metal” out of the S-IC, Stafford recalled, “making the booster walls more flexible and more prone to pogo. Also, there was a ground stabilization bar inside the cockpit that connected our crew couches to the rear bulkhead. It was supposed to be removed before launch, but somebody forgot. The bar magnified the pogo!”

The ignition of the Saturn’s second stage, the S-II, came with a noticeable wham, which slammed the astronauts back into their seats. “But the pogo stayed with us,” Gene Cernan wrote, “worse than ever, as another million pounds of liquid hydrogen and liquid oxygen … burned hot and hard for seven minutes and we accelerated with breathtaking speed.” This acceleration was accompanied by disturbing moans and creaks from the rocket, as its metal strained under excessive pogo forces. Stafford, Young, and Cernan could feel the effect, 20 stories beneath them, but could see nothing, for the command module’s only uncovered window was directly in front of the commander’s face.

Demonstrating the smallness of the Apollo command module, this training view of the Apollo 10 crew reveals the cramped conditions of their voyage to the Moon. Photo Credit: NASA

Their momentary blindness ended when Young pushed the buttons to jettison the Saturn’s escape tower and launch shroud. These blew away with a tremendous roar, and the cabin was instantly flooded with sunlight. The violence of the event surprised Cernan, to the extent that he was momentarily convinced that Apollo 10 had been torn loose from the booster. Still, the view was electrifying, as Africa’s western shore and the startling azure blue of the Atlantic Ocean, lapping its coastline came into sight. Stafford, Young and Cernan had crossed the second-largest ocean in the world…in a mere 12 minutes.

Yet they were not quite in orbit. “We got another stomp when the third stage kicked in,” wrote Cernan. After the ignition of the S-IVB, the ride turned from an intense rocking and rolling into something he could only describe as being borne along with the grace and style of a Cadillac. Finally, when the S-IVB fell silent, Apollo 10 was in a 118-mile (190-km) “parking” orbit, around Earth, ready to commence its journey to the Moon…but with one question still unanswered: Had the pogo damaged their spacecraft?

Flight Director Glynn Lunney and his Black Team of controllers could see nothing amiss in their telemetry, but they had an uneasy feeling that something was not right. Eventually, Lunney voted with the data on his screen, which told him that nothing was wrong. When Apollo 10 picked up communications with the Carnarvon tracking station on Honeysuckle Creek in Australia, the astronauts received a “Go for TLI.”

One hundred and sixty thousand kilometres from home, this electrifying view of Earth from Apollo 10 reveals many of the lands around the Mediterranean, from whence ‘Western’ civilisation arose. Photo Credit: NASA

The six-minute Trans-Lunar Injection burn of the S-IVB began at 3:19 p.m. EDT, a little more than four hours into the mission, when the third stage’s single J-2 engine came to the life for the second time that day. For three minutes of the burn, all went well. Apollo 10 accelerated briskly toward the velocity it would need to climb out of Earth’s gravitational “well” and set course for the Moon. Unfortunately, the velocity was accompanied by some disturbing vibrations through the vehicle. At their worst, these vibrations were so bad that the astronauts could hardly read their instruments. Tom Stafford kept his gloved hand tightly closed around the controller which would enable him to shut down the S-IVB and abort the mission. “We’re getting a little bit of high-frequency vibrations in the cabin,” he radioed, calmly. “Nothin’ to worry ‘bout.”

It felt like “flutter”—the aeroelastic phenomenon in which aerodynamic forces on an object, together with an aircraft’s natural vibration, produce rapid periodic motions—and Stafford was privately fearful that it would necessitate an abort. With six months left to meet President Kennedy’s goal, he simply could not bring himself to twist the abort controller. “An abort would leave us in a giant, looping orbit,” he later wrote. “There would be no visit to the Moon, no test of the lunar module, just a two-day wait for re-entry.”

For Stafford, the decision was a no-brainer: he would not call an abort. “If she’s gonna blow,” he told himself, “she’s gonna blow.” On the other side of the cabin, Cernan was thinking of the abort procedures, but also could not bring himself to execute them. Stafford repeatedly whispered, “C’mon, baby.” At length, after six minutes, the S-IVB shut down, on time. Apollo 10’s velocity was right on the money at the 23,900 mph (38,500 km/h) needed to begin the three-day voyage to the Moon. The scare illustrated a harsh truth: On the United States’ second journey beyond Earth orbit, nothing could be taken for granted and everything was still a huge unknown.

Gene Cernan summed up their feelings perfectly in his autobiography. Years of flying the most advanced aircraft on Earth, pushing them to their limits, and finding answers to pre-determined questions now counted for nothing. “Out here,” Cernan wrote, “confronting a foreign and hostile environment, where there was no horizon, no up or down, and where speed and time take on new meaning, we not only didn’t know the answers…we didn’t know the questions!”


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Odp: [Houston We Have a Podcast] Apollo 10
« Odpowiedź #5 dnia: Czerwiec 02, 2019, 16:43 »

'We Have Arrived': Remembering Apollo 10, 50 Years On (Part 3)
By Ben Evans, on June 2nd, 2019 [AS]

The rugged, forbidding lunar landscape, seen from Apollo 10. Photo Credit: NASA

Four hours after a bone-jarring launch from Cape Kennedy—marking the first-ever space mission to originate from Pad 39B—and an equally rattling ride through Trans-Lunar Injection (TLI), on 18 May 1969 the crew of Apollo 10 were finally on their way to the Moon. Their mission to lunar orbit would clear the final hurdles before humanity’s first piloted landing on an alien world on Apollo 11. Those hurdles included Commander Tom Stafford and Lunar Module Pilot (LMP) Gene Cernan guiding the spider-like Lunar Module (LM), which they had nicknamed “Snoopy”, to within nine miles (15 km) of the Moon’s surface. In doing so, they left Command Module Pilot (CMP) John Young to become the first man ever to fly solo in orbit around the Moon.

As outlined in last weekend’s AmericaSpace history article and the first instalment of this four-part feature, Apollo 10 was a fundamentally critical stepping-stone in evaluating the tools, techniques and technologies needed to bring humans down to the lunar surface.

Mission controllers anxiously watch the ‘transposition and docking’ of lunar module Snoopy, four hours into the Apollo 10 mission. Photo Credit: NASA

Shortly before 4 p.m. EDT on 18 May, Young executed his first major task of the mission by pulling Apollo 10’s Command and Service Module (CSM), dubbed “Charlie Brown”, away from the spent final stage of the mammoth Saturn V rocket. He smoothly rotated the craft by 180 degrees in a “transposition and docking” maneuver to collect Snoopy. By now, in the mysterious void between Earth and the Moon—known as “cislunar space”—the view of the Home Planet had changed significantly. In the hours after launch, it resembled a gigantic map, unfolded beneath” them, but now, as they headed toward the Moon, it had shrunk noticeably, from filling Charlie Brown’s windows to something the size of a basketball. By the time they reached lunar orbit, it appeared little bigger than a marble. “For the first and only time in my spaceflights,” Stafford later wrote in his autobiography, We Have Capture, “I felt strange.” They were a long way from home.

For Cernan, a man born and raised in the Catholic faith, yet by his own admission “not an overly religious person”, it redefined everything he thought he knew; out here, the smallness of Earth, its continents, and even its vast ocean trenches were dwarfed by the true infinity of the Universe. This beautiful, perfect, limitless expanse of nothingness must, he reasoned, prove the reality of some form of Creator, but to comprehend the matter further went beyond his mortal understanding. “Someone, some being, some power, placed our little world, our Sun and our Moon where they are in the dark void,” Cernan pondered, “and the scheme defies any attempt at logic.”

These thoughts were undoubtedly with all three men at quiet times throughout their voyage, but such were the demands of a lunar expedition that no one had the opportunity to dwell upon them. Notions of infinity came figuratively back to Earth by the grind of daily life aboard ship. Achieving the late President John F. Kennedy’s challenge was on everyone’s mind. None of the astronauts wanted to screw up, get sick or miss a step in the timeline. Sickness was a major concern. All three men had experienced stuffy heads upon arriving in space, although the sensations cleared within a few hours for both Stafford and Young. For Cernan, it lingered a little longer, but by 20 May he felt fine.

It was a little ironic that Apollo 10 was the first American flight in which bread—real bread—officially became part of the crew’s pantry. “Officially”, that is, because some years earlier one member of Stafford’s crew was reprimanded for taking a corned-beef sandwich into space. On the Gemini 3 mission, John Young arranged for the treat to be sneaked aboard as a surprise for his crewmate, Virgil “Gus” Grissom. Unfortunately, after taking a bite, Grissom had been obliged to put it away when it started to crumble and bits began to float around the cabin. This problem was solved in time for Apollo 10: slices of white and rye bread were flushed with nitrogen, which kept them fresh for up to two weeks and prevented them from drying out and crumbling into fragments.

Drinking, on the other hand, gave Tom Stafford a rather unpleasant surprise when he forgot to open a valve to the ship’s water tank and was rewarded with an evil-tasting dose of highly chlorinated water. There were other problems, too. The drinking water was a by-product of the hydrogen-oxygen fuel cells, which generated Charlie Brown’s electricity, and on previous missions astronauts had complained about the presence of hydrogen bubbles in it. A new drinking bag was created, with a handle that enabled the astronauts to whirl it around and separate the gas from the water. Unfortunately, it did not work and caused the hydrogen bubbles to settle at the bottom, then remixed with the water when they took a sip. All three astronauts suffered what NASA euphemistically referred to as “gas pains”, but they avoided an outbreak of diarrhoea.

Maybe the quality of the drinking water affected the men’s appetites, which remained low throughout the mission. To be fair, the food was by no means haute cuisine: even Don Arabian, head of the Apollo Test Division—who once described himself as “a human garbage can”—struggled to find anything appealing in the tasteless sausage patties and minuscule chicken bits. Early in May, he volunteered to try Apollo 10’s fayre for four days, but after three days of chewing food with a taste like granulated rubber, he understandably lost the will to live! Some foods were better than others, of course, and some could even be eaten quite “normally” with a spoon; but the dehydrated dishes needed reconstituting with water and that meant injecting an uncomfortable amount of hydrogen gas into their meals. Not surprisingly, the men ate little during their mission to the Moon.

As Command Module Pilot (CMP) of Apollo 10, John Young became the first human being to fly solo in orbit around another celestial body. Photo Credit: NASA

Still, with Snoopy attached to Charlie Brown’s nose, Apollo 10 provided a relatively large space in which to live and work. For Tom Stafford, whose two previous Gemini missions had been like sitting in the front seat of a Volkswagen Beetle, it felt almost like having an attic or an extra apartment. The job of opening up that apartment fell to Gene Cernan, who floated through the tunnel early on 19 May, to be greeted by a snowstorm of floating fiberglass crumbs! It turned out that a Mylar cover on the command module’s tunnel wall had torn loose, releasing the cloud of snowy particles, which itched like hell, took hours to vacuum up, stuck to hair, eyebrows, and lashes, and left Cernan looking “like a hound dog who’d been in a chicken coop”.

By the following morning, Apollo 10 was more than 150,000 miles (240,000 km) from Earth and its velocity had slowed to a relatively puny 2,480 mph (4,000 km/h), as the gravitational influence of the Home Planet waned. Shortly thereafter, it entered the Moon’s sphere of gravitational influence and began to accelerate as it “fell” toward its objective. “Our trajectory,” wrote Stafford, “had been so accurate that three of our four mid-course correction burns had been cancelled.” The only mid-course burn of Charlie Brown’s large Service Propulsion System (SPS) engine changed their velocity by barely 33 mph (54 km/h). It was so accurate that the last two burns were canceled. This also served to calibrate the engine for the forthcoming entry into lunar orbit.

Captured from one of Apollo 10’s colour telecasts, this view reveals craters to the west of the Sea of Fertility, on the lunar near side. Photo Credit: NASA

Eight and a half thousand miles (14,000 km) from the Moon, they made a television transmission, giving their audience another view of Earth, which by this point had diminished to somewhere between a grapefruit and an orange. Such views gave Stafford a chance to jab at the British Flat Earth Society that “the Earth is round”. Perhaps the use of the word “round”, rather than “spherical”, pre-empted the society president’s defiant response: “Colonel Stafford, it may be round, but it’s still flat, like a disk!” Yet the television camera was a marvel and gave the eager audience an unprecedented sense of “being there”. By the end of the flight, Apollo 10 made 19 telecasts, spanning almost six hours and providing such a novel dimension for what was happening in space that Stafford, Young and Cernan received a special Emmy award. The resolution was so good that when they filmed the transposition and docking with Snoopy, viewers could actually count the tiny metal rivets on the lunar module’s skin. “Finally,” wrote Cernan, “the taxpayer would get a look at where their money was going.”

If the taxpayer knew where their money was going, it was not until Apollo 10 passed around the limb of the Moon late on the afternoon of 21 May that the astronauts finally saw where they were going. Until then, their goal had been virtually invisible. “During the entire mission,” wrote Stafford, “we had been facing its night-time side, which was almost totally black. Peering through his navigation equipment, John Young had been able to find a place in the sky where the stars were occluded, so we were pretty sure the Moon was out there.” The trajectory planners and mathematicians had guided them to the Moon with pinpoint accuracy and there it was, the lunar surface, just 60 miles (95 km) from them; so close, it seemed, that they could almost touch it.

A few minutes before five in the evening, the SPS engine slowed Apollo 10 by 3,660 mph (5,900 km/h) and inserted it into an elliptical orbit. “I pitched the spacecraft over,” wrote Tom Stafford, “so we could get a good view of the surface. We were looking at the so-called far side of the Moon, the tide-locked side facing away from Earth.” Visible in sharp relief were forbidding mountains, pockmarked ridges and furrows, and thousands of craters—including the gigantic Tsiolkovsky basin, named after the humble Russian schoolmaster today revered as the father of theoretical cosmonautics. Indeed, the lunar far side looked so tortured that it reminded Stafford of a plaster-of-Paris cast.

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Video Credit: NASA

On the near side, the dark, basalt-rich Sea of Crises was easy to spot, a flat-floored, wrinkle-edged blob, clearly visible to the astronauts in the wonderful, eerie clarity of the early lunar morning. It really stood out, said Young. Stafford added that the ridges running across its floor went “straight down just like the Canyon Diablo in New Mexico”. Originally given the Latin name “seas” (mare) by early astronomers—who mistook their darkness for being open water—the lunar mare were actually formed by ancient volcanic eruptions, many of which (as a result of the samples collected by astronauts on the Moon) have been dated to between three and four billion years old. Their intrinsic darkness comes from their iron-richness and some two dozen maria on both the near and far sides cover around 16 percent of the lunar surface.

Two orbits after their arrival, a second SPS burn roughly circularized Apollo 10’s path around the Moon at an altitude of a little more than 69 miles (110 km). As the astronauts gawped through Charlie Brown’s windows, their eyes adapted to distinguish finer gradations of color in this lifeless world. It was now early morning, lunar time, and the surface exuded a vivid spectrum from white to black and a mix of greys, tans, sickly pale yellows, and hints of red in some craters. The spectacle was completed by the awe-inspiring sight of their first Earthrise on the lunar horizon; even at this distance—some 240,000 miles (370,000 km) from home—they could still pick out the ice caps, the vast bulk of Antarctica, the southward-projecting finger of Baja California, the intense flecks of white cloud, and the iridescent blues of the oceans.

Moving into their third orbit around the Moon, Stafford, Young and Cernan again broke out the camera and treated their audience to the first-ever televised images of Earth’s closest celestial neighbor in color. Although these early images were somewhat “washed-out”, thanks to the height of the Sun in the sky, they improved as Apollo 10 headed westward, where the illumination was oblique and the terrain was brought into sharper relief. Capcom Joe Engle in Mission Control described the vast expanse of the Sea of Fertility as “unbelievable”. Other controllers were dumbstruck by the Langrenus impact crater, its walls up to two miles (3.2 km) high in places, its central, cone-like peak rising 3,200 feet (1,000 meters) from an irregular, boulder-strewn floor that Apollo 8 astronaut Jim Lovell, the previous December, had described simply as “huge”.

Stafford keyed his mike: “Houston, tell the world we have arrived!”


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Odp: [Houston We Have a Podcast] Apollo 10
« Odpowiedź #6 dnia: Czerwiec 12, 2019, 07:53 »
'Down Among 'Em': Remembering Apollo 10, 50 Years On (Part 4)
By Ben Evans, on June 9th, 2019 [AS]

The Apollo 10 and 11 crews in discussion, after the completion of the Apollo 10 mission. Around the table from foreground are Apollo 11 Command Module Pilot (CMP) Mike Collins, Apollo 11 Lunar Module Pilot (LMP) Buzz Aldrin, Apollo 10 LMP Gene Cernan, Apollo 10 Commander Tom Stafford, Apollo 11 Commander Neil Armstrong and Apollo 10 CMP John Young. Photo Credit: NASA

Fifty years ago, this spring, the three astronauts of Apollo 10 circled the Moon, marking humanity’s second voyage to our closest celestial neighbor. Their spacecraft had many of the provisions needed to execute a landing—a Command and Service Module (CSM), which they had nicknamed “Charlie Brown”, and a Lunar Module (LM), “Snoopy”—but on this “F mission”, Commander Tom Stafford, Command Module Pilot (CMP) John Young and Lunar Module Pilot (LMP) Gene Cernan performed a full dress rehearsal for the first landfall on alien soil. They would test the LM’s descent engine, guidance and navigation systems and radar and in doing so would clear the final hurdle in anticipation of the historic Apollo 11 voyage in July.

Apollo 10 flight profile. Image Credit: NASA

In doing so, they would come face to face with the immense risk that they were taking and would depart the Moon fully aware that the journey was fraught with danger and complexity. High above the Moon, Stafford and Cernan shimmied through the short tunnel from Charlie Brown into Snoopy. Their day began with an irritating problem with a radar gauge, then a communications difficulty and later an error with the lunar module’s gyroscopic stabilization platform. Precisely on schedule, Apollo 10 disappeared behind the Moon on its 12th orbit and, when the radio blackout ended 40 minutes later, Stafford jubilantly announced that Charlie Brown and Snoopy had successfully parted company. After the undocking at 2:00 EDT, Young used his thrusters to withdraw from the lander.

“You’ll never know how big this thing gets when there ain’t nobody in here but one guy,” he drawled.

“You’ll never know how small it looks when you’re as far away as we are!” countered Cernan.

“Yeah,” continued Stafford. “Don’t get lonesome out there, John.”

As the range opened, it was Young’s task to activate a homing receiver for the lander’s rendezvous radar, and he had to toggle a switch several times to make it work properly. Then a glitch with the orientation of Snoopy’s antennas affected communications with Charlie Brown. Next, the link between Charlie Brown and Houston fell silent. “A quick check of the system,” wrote Stafford in his memoir, We Have Capture, “showed that a breakdown had occurred in the line between Houston and the tracking station in Goldstone, California.” At length, the problems ironed out. For the next eight hours, Young would score a new record: the first man to fly solo in lunar orbit.

Somewhere behind the Moon, during the first of Snoopy’s four independent orbits, Stafford fired the descent engine for the first time to reduce its velocity and begin dropping toward the lunar surface. He started the engine at its minimum thrust level—first 10 percent, waited for a few seconds, then opened the throttle to 40 percent—and, from his vantage point, John Young reported that they were moving noticeably away from him. For the men aboard the lander, on the other hand, the ride seemed relatively slow and established Snoopy in an elliptical orbit with a “perilune” of nine miles (15.4 km) above the surface. The two astronauts, broadcasting on “hot-mike” to the whole world, were exultant.

“We is down among ’em, Charlie!” radioed Cernan.

“Rog, I hear you’re weaving your way up the freeway,” replied fellow astronaut Charlie Duke, the capcom in Mission Control.

Twelve miles (20 km) above the Moon, as intended and precisely on cue, the radar detected the looming surface and began feeding rate-of-descent and altitude data into Snoopy’s computer. The lunar mountains, rushing past below, seemed almost close enough to touch, their appearance and texture resembling wet clay. As they approached Mare Tranquillitatis—an area targeted for the first landing, running along an imaginary “lane” of physiographic features memorized from months of studying maps and charts—the men were astonished by the barrenness of the terrain. “There are enough boulders around here,” Stafford breathed, “to fill up Galveston Bay.”

Since their assignment to the mission the previous November, Stafford and Cernan had spent hundreds of hours poring over maps and photographs from the unmanned Lunar Orbiters of two of the candidate landing sites for Apollo 11. Both lay in the relatively flat Tranquillitatis region and the men had even tried to simulate part of their trajectory aboard a T-38 aircraft back on Earth. When the time came to fly over the favoured landing spot, “Site 2”, for real, they knew the craters, mountains, rilles, bumps, hollows and furrows so well that they literally formed a familiar “road”, guiding them to the landing zone. To their eyes, it was a virtual lunar highway and they had nicknamed it “U.S. 1”. Along the way, a range of low mountains was called the “Oklahoma Hills”, a rille which split into a pair of craters was dubbed “Diamondback” and “Sidewinder” and one ridge was even named in honor of Stafford’s then-wife, Faye.

Commander Tom Stafford, pictured during one of Apollo 10’s color telecasts. Photo Credit: NASA

Attempting to shoot a photograph every three seconds as Snoopy passed over Site 2, Stafford was annoyed when the “goddamn” Hasselblad camera issued an ominous puff of smoke and jammed. (He later apologized to Victor Hasselblad upon his return to Earth.) It was the first of a number of unfortunate outbursts from Snoopy’s cabin. Deprived of his camera, Stafford resorted to verbal reports, comparing the inhospitable appearance of the site to the high desert near Edwards Air Force Base, Calif. If Apollo 11 astronauts Neil Armstrong and Buzz Aldrin were to find themselves heading for the “near” end of the target ellipse, then they would have a smooth landing; but he advised that a landing at the “far” end would demand additional fuel to find a spot free of boulders. Just beyond Tranquillitatis, and an hour after the first burn, Stafford again fired Snoopy’s descent engine, this time using full throttle to accelerate them by almost 125 mph (200 km/h) and enter an eccentric orbit that simulated an ascent from the surface.

When the time came to jettison the descent stage and return to redock with Young, Stafford oriented the vehicle correctly but noted a slight yaw rate on his attitude indicators. “Telemetry suggested we might have an electrical anomaly,” he wrote, “so I started to troubleshoot the problem.” Shortly thereafter, Cernan, thumbing through his checklist, switched control from the Primary Navigation, Guidance and Control System (PNGS) to the Abort Guidance System (AGS). The former provided an exact navigational reading, whereas the latter would “get us the hell out of there if unexpected trouble cropped up.”

In case Armstrong and Aldrin needed to abort in a hurry—punching their ascent stage away if their descent went awry—a test of the AGS in lunar orbit was critical. Stafford and Cernan had rehearsed it a hundred times in the simulator. Clad in their bulky suits, however, both men found it difficult to hit the right switches.

An instant after Cernan set the control mode of the AGS to “attitude hold”, Stafford reached across and inadvertently changed it to “auto”.

Snoopy’s ascent stage, pictured during final approach for docking, as seen by John Young from Charlie Brown’s windows. Photo Credit: NASA

Seconds later, they were ready to blow the four explosive bolts to separate the ascent stage from the descent stage and begin to trek back to Charlie Brown. Suddenly, and without warning, Snoopy went berserk, lurching wildly in both pitch and yaw axes. “Gimbal Lock!” shouted Stafford urgently, believing the lander’s gyros to have frozen. Cernan, over hot-mike and with the whole world listening in, yelled with unfortunate clarity: “Son-of-a-bitch! What the hell happened?” As the menacing lunar terrain, the black sky and the grim line of the horizon alternately flashed in Snoopy’s windows, both men knew they had just seconds to resolve whatever was wrong.

By activating the AGS and setting it to “auto”, Stafford had in effect instructed Snoopy’s radar to begin searching for Charlie Brown and the abort guidance system was now causing the lander to flip wildly around its center of mass. Quickly, he pushed the button to jettison the descent stage and steadily regained control of the gyrating ascent stage. Fearing that the inertial measurement unit was close to gimbal lock, Stafford executed a pitch maneuver, started working the attitude switches and finally calmed the ascent stage down. From Cernan’s initial shout to Stafford’s final report to Houston that Snoopy was back under control, three minutes elapsed.

Artistic visualization of the rendezvous operation between the Command and Service Module (CSM), Charlie Brown (foreground), and Lunar Module (LM), Snoopy (background). Image Credit: NASA

Those minutes were unnerving not only for Stafford and Cernan, but also for John Young, listening helplessly from Charlie Brown. “I don’t know what you guys are doing,” he drawled in his typically understated manner, “but knock it off. You’re scaring me!”

Years later, Cernan and Stafford would both say that it was a classic piloting error. “Neither Tom or I can be sure,” Cernan related in his autobiography, The Last Man on the Moon, “but when it came time to stage…there was some switch that had to be changed, and I changed it. And I’d be willing to bet that…I put the switch in the new position and Tom went ahead and moved it back to the old one. His action was to move the switch. I’d already done it for him. But he didn’t know that and, when he moved the switch, he just moved it back to where it was. In effect, we created the problem!”

Although the cause of the glitch was easily solvable in time for Apollo 11, the episode highlighted that nothing could be taken for granted on a lunar expedition. Charlie Duke, helpless to assist, had warned them from his data that they were close to gimbal lock, but things were moving far too quickly for him or anyone else in Mission Control to help. By contrast, the return to Charlie Brown was perfect; Stafford found Snoopy’s ascent stage a little difficult to hold steady, but Young had no problem docking and all three men were greeted by the welcome “ripple-bang” of a dozen capture latches snapping shut. “Snoopy and Charlie Brown are hugging each other,” chortled Stafford. A few minutes later, back in the command module, Young received a couple of hugs, too.

The Home Planet, as seen from a distance of 100,000 miles (160,000 km), during the Apollo 10 mission. Photo Credit: NASA

Several days later, on 26 May 1969, the Apollo 10 command module hit Earth’s atmosphere at a lunar-return velocity of close to 25,000 mph (40,000 km/h). Cernan remembered an enormous white-and-violet “ball” of flame, literally sweeping up the spacecraft like a glove. “It grew in intensity,” he wrote, “and flew out behind us like the train of a bride’s gown, stretching a hundred yards, then a thousand, then for miles…and the whole time we were being savagely slammed around inside the cabin.”

To some people, the fire and brimstone nature of re-entry illustrated God’s wrath with this foul-mouthed team of space flyers. One man who was not happy, was an over-zealous minister named Rev. Larry Poland. He was vocal in complaining that Stafford’s crew had taken “the language of the street” with them to the Moon, and urged them to apologize for their “profanity, vulgarity and blasphemy.” However, recognizing the reality that its men were in a life-or-death situation, NASA managers stood by the crew, saying they had “acted like human beings.” After splashdown, they were greeted with tongue-in-cheek notices, one of which read: The Flight of Apollo 10: For Adult Audiences Only. Bob Gilruth, the head of the Manned Spacecraft Center (MSC) in Houston, Texas, had burst out laughing when he heard the swearing, and veteran flight director Chris Kraft was philosophical in his autobiography, Flight. “They were out there doing man’s work at the Moon,” Kraft wrote. “If a cuss word or three slipped out, well, who the hell cared anyway?”

The Apollo 10 command module descends to splashdown on 26 May 1969. Photo Credit: NASA

Larry Poland cared greatly and laughing it off was not good enough. In the days and weeks after the mission, hundreds of letters and telegrams flooded into NASA’s Washington, D.C., headquarters, some tolerating the language, others condemning it. John Young was not involved and Tom Stafford (famously nicknamed “Mumbles”) had uttered his profanities under his breath. Gene Cernan, though, was well and truly in Rev. Poland’s firing line. His words could neither be misconstrued or explained away. At a news conference, Cernan apologized to the people he had offended and thanked those who understood how he came to say what he did. Privately, though, he was furious. It made no difference, he wrote, that Poland accepted his apology and forgave him, for Cernan “never got around to forgiving that self-righteous prig!”

It was the only unfortunate incident to blight a mission which had otherwise proved enormously successful; by verifying the performance of the entire Apollo spacecraft in orbit around the Moon, Apollo 10 had cleared virtually every remaining hurdle in the path to the first lunar landing. By the start of June 1969, 50 years ago, this week, the first manned landing on alien soil was only weeks away.