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Remembering Shuttle Discovery's Miracle Mission, 35 Years On (Part 1)
By Ben Evans, on January 20th, 2020


Thirty-five years ago, this week, Discovery flew Mission 51C, the shuttle’s first totally classified mission. Photo Credit: NASA

“Miracle” is a term often applied to many aspects of the space program: from Yuri Gagarin’s pioneering flight aboard Vostok 1 to the historic first manned lunar landing and from the triumph of Apollo 13 to the safe return of Alexei Ovchinin and Nick Hague after their abortive Soyuz MS-10 launch attempt. But the liftoff of shuttle Discovery on 24 January 1985—35 years ago, this coming week—marked a miracle of another kind. In a sense, it was literally miraculous that Discovery made it to space at all…both metaphorically and literally, as the Challenger accident investigation later revealed. For the cold-weather conditions at the time of Mission 51C’s launch proved so damaging to the O-ring seals in the twin Solid Rocket Boosters (SRBs) that the crew came within a hair’s breadth of disaster.


Mission 51C remains the shortest “operational” mission ever undertaken by the Space Shuttle. The flight lasted just over three days. Video Credit: NASA/Matthew Travis/YouTube

When Commander Ken Mattingly, Pilot Loren Shriver and Mission Specialists Ellison Onizuka and Jim Buchli were named as the crew of STS-10 in October 1982, they confidently expected to fly Challenger in September 1983 on the first classified shuttle mission for the Department of Defense. It would put the shuttle’s advertised capability as a “truck” for the United States’ largest and most sensitive national security assets to the ultimate test. They were later joined by an Air Force Manned Spaceflight Engineer (MSE) named Gary Payton, who would serve as Payload Specialist.

Unfortunately, the mission quickly ran into problems when the Inertial Upper Stage (IUS) booster, built by Boeing for the Air Force, failed to properly insert the first Tracking and Data Relay Satellite (TDRS) into orbit in April 1983. Mattingly’s mission was manifested to use the same type of booster. His flight hung in limbo whilst an investigation panel pored over the engineering data and made recommendations. Boeing, meanwhile, spent a year correcting the problems and recertifying the IUS. By November 1983, Mattingly’s flight was redesignated Mission 41E and rescheduled for July 1984, but within months it succumbed again to extensive delay. When NASA issued an updated shuttle manifest in May 1984, it had vanished entirely and Mattingly and his men were reassigned to Mission 51C, still on shuttle Challenger and now set for December 1984. “That,” said Loren Shriver, with an air of understatement, “is when we started to learn that the numerical sequence of the numbers of the missions didn’t mean a lot.”



Since the conception of the Manned Spaceflight Engineer (MSE) program, the intent was to fly a dedicated officer aboard each classified flight. For Mission 51C, it would be Air Force Major Gary Payton (back left). The other NASA crew members were Loren Shriver (front left) and Ken Mattingly (front right), with Jim Buchli and Ellison Onizuka behind. Photo Credit: NASA

For a time, Shriver wondered if he would ever fly, but unlike other shuttle missions at the time, in which payloads were interchangeable, they were a Department of Defense crew. “You were kind of linked to it, as long as there some thought that it was going to happen, and it never did completely go away,” he remembered. “It just went kind of inactive for a while, then came back as 51C.” Shriver was unsurprised that the crew were all active-duty military men. “I think NASA believed that it didn’t have to do that,” he said, “but I think it also believed that things would probably go a lot smoother if they did.”

Flying a classified mission posed its own problems for Mattingly. Within NASA, he had become familiar with the practice of sharing information, particularly about the shuttle. With a Department of Defense payload, the crew could not publicly discuss the particulars of their flight, and the exact details were made available to only a handful of engineers, technicians and Air Force managers. “I had some apprehension,” Mattingly said, “about could we keep the exchange of information timely and clear in this small community when everybody around us is telling anything they want and we’re keeping these secrets. Security was the challenge of the mission.”



It became a staple of each Department of Defense mission for a patriotic crew patch, with little indication as to its primary objective. Image Credit: NASA

Cipher locks were placed on training materials, “but then you had to give the code to a thousand people, so you could go to work!” They were given a classified meeting room in the astronaut office, a classified safe for their documents…and a classified phone, with an unlisted number. In the entire span of their training time together, the phone rang just once. It was a sales call, asking Mattingly if he wanted to buy a new long-distance service…

The ridiculous levels of secrecy became even more laughable at other times, particularly when the astronauts were obliged to “disguise” the places where they were doing their training. They would file T-38 flight plans to Denver, Colo., then file new ones to the San Francisco Bay area, then rent a car to reach their military destination at Sunnyvale, Calif. They were asked to do their mission training during the daytime and at night, to keep the launch time secret from prying eyes, or anyone who could be bothered to put two and two together, but all this furore never convinced Mattingly that anyone really cared. On one occasion, their office secretary booked motel rooms for them—“secretly”, of course—but the four astronauts, crammed into a decrepit old rental car, with Ellison Onizuka at the wheel, had a surprise when they arrived. Jim Buchli spotted it first.



Commander Ken Mattingly (right) leads his men out of the Operations and Checkout Building early on 24 January 1985. Photo Credit: NASA

“Stop here,” he said. “Now, let’s go over this one more time. We made extra stops to make sure that we wouldn’t come here directly…and they can’t trace our flight plan. We didn’t tell our families. We didn’t tell anyone where we were. And we can’t tell anyone who we’re visiting. Look at that.” Four sets of eyes peered over toward their “secret” motel and beheld an enormous banner, emblazoned with the legend: WELCOME, 51C ASTRONAUTS. “How’s that for security?” chuckled Mattingly.

When Challenger returned from her previous flight in October 1984, she was scheduled to be relaunched on 8 December for Mission 51C, but inspections revealed that almost 5,000 of the delicate thermal protection tiles had become de-bonded during re-entry. One tile, located in the vicinity of the left-hand wing chine, had completely separated from the airframe and, although not a catastrophic problem in itself, revealed a far more worrying issue. A vulcanizer material, known as “screed”, used to smooth metal surfaces under tile bonding materials, had softened to such an extent that its “holding” qualities were impaired. Subsequent investigation revealed that repeated injections of a tile waterproofing agent called “sylazane”, coupled with the effects of six high-temperature re-entries, had caused degradation in the bonding material. By the time Challenger flew her next mission, the use of sylazane had been scrapped. In the interim she was reassigned to Mission 51E, scheduled for launch in March 1985, and 51C switched to Discovery with a launch date in late January 1985. Years later, Loren Shriver did not remember any significant mission impact, other than the six-week launch delay from switching orbiters.

Due to the classified nature of the flight, some Air Force officials did not even want the precise launch date, or even the astronauts’ names, released to the public. Loren Shriver was not alone in his amazement at this excessive insistence on secrecy. “We weren’t going to be able to invite guests for the launch in the beginning,” he told the NASA oral historian. “This is your lifelong dream and ambition. You’re finally an astronaut and you’re going to go fly the shuttle and you can’t invite anybody to come watch …We finally got them talked into letting us invite … 30 people, and then maybe some car-pass guests, who could drive out on the causeway … but trying to decide who, among all of your relatives and your wife’s relatives, are going to be among the 30 who get to come see the launch, well, it’s a career-limiting kind of decision if you make the wrong decision. You have part of the family mad at you for the rest of your life!”



Mission 51C roars into orbit on 24 January 1985, kicking off the shuttle program’s first dedicated Department of Defense assignment. Photo Credit: NASA

Fortunately, Shriver’s family and most of his wife’s relatives were from Iowa, which was sufficiently distant for many to be unable to make the journey to Florida. Privately, Shriver and his crewmates worried that their inability to discuss the mission openly might compromise their preparedness and the thoroughness of their training. It must have been an unusual sight to behold the 51C stack, sitting on Pad 39A, with only a select number of military and NASA personnel knowing precisely when the launch would take place; in fact, the media had been told to expect liftoff within a three-hour “block” of time, sometime between 1 p.m. and 4 p.m. EST on 23 January 1985. Freezing weather conditions kept Discovery on the ground that afternoon, but the situation seemed to have improved marginally by the following day.

For the spectators at the Kennedy Space Center (KSC), the famous countdown clock, which normally ticks away the final minutes and seconds, showed a blank face, and all communications between launch controllers and the flight crew were kept quiet.

Then, at 2:41 p.m. EST, the blackout suddenly ended with a statement from the launch commentator: “…T-9 minutes and counting. The launch events are now being controlled by the ground launch sequencer…”

The spectators braced for the first shuttle launch of 1985.


Source: https://www.americaspace.com/2020/01/20/remembering-shuttle-discoverys-not-so-secret-mission-35-years-on/
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Odp: [AS] Remembering Shuttle Discovery's Miracle Mission, 35 Years On
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Remembering Shuttle Discovery's Miracle Mission 51C, 35 Years On (Part 2)
By Ben Evans, on January 26th, 2020



Discovery touches down at the Kennedy Space Center on 27 January 1985, following the shortest operational flight in the shuttle’s 30-year history. Photo Credit: NASA

Thirty-five years ago, this week, the crew of shuttle Discovery—Apollo veteran Ken Mattingly, together with “rookie” astronauts Loren Shriver, Jim Buchli and Ellison Onizuka and Air Force Manned Spaceflight Engineer (MSE) Gary Payton—flew Mission 51C, the first wholly classified voyage of the Space Shuttle era. As outlined in last week’s AmericaSpace history article, it was conducted in near-total secrecy and even the precise launch time did not become clear to the general public until the countdown clock emerged from its pre-planned hold at T-9 minutes. Until then, spectators at the Kennedy Space Center (KSC) in Florida beheld a blank face on the famous clock.

Then, at 2:41 p.m. EST on 24 January 1985, the blackout ended abruptly with a statement: “T-9 minutes and counting. The launch events are now being controlled by the ground launch sequencer…”



Launch and landing of the secret Mission 51C, which took place 35 years ago, this month. Video Credit: NASA/YouTube

Thus began not only the shortest operational mission of the shuttle program, but also a flight which would suffer significant damage to both the primary and secondary O-rings of its Solid Rocket Booster (SRB) joints and which would take center-stage in the Challenger accident investigation a year later.

Discovery thundered aloft at 2:50 p.m. EST. The ascent was unique, compared to previous flights, in that communications between Mattingly’s crew and Mission Control were kept strictly under wraps, with only the launch commentator reading off a string of standardized calls pertaining to the performance of the shuttle’s main engines, its fuel cells, its Auxiliary Power Units (APUs) and its steadily increasing altitude and velocity. No indication was given as to the precise duration of Mission 51C—one source noted that NASA would reveal this detail only 16 hours prior to the scheduled landing—and few other details were ever released about this most secret of flights.

Since the conception of the Manned Spaceflight Engineer (MSE) program, the intent was to fly a dedicated officer aboard each classified flight. For Mission 51C, it would be Air Force Major Gary Payton (back left). The other NASA crew members were Loren Shriver (front left) and Ken Mattingly (front right), with Jim Buchli and Ellison Onizuka behind. Photo Credit: NASA

More than three decades later, it is suspected that Mattingly and his men deployed a spacecraft codenamed “Magnum”: a signals intelligence satellite, operated by the National Reconnaissance Office (NRO) and the Central Intelligence Agency (CIA), which was boosted into near-geostationary orbit by an attached Inertial Upper Stage (IUS) booster. Reports have indicated that the TRW-built Magnum weighed in the region of 4,800-6,000 pounds (2,200-2,700 kg) and was notable for its physical size, with 330-foot-wide (100-meter) anteannas to collect radio frequency signals from Earth. The payload was deployed during Discovery’s seventh orbit.

Payton was the first MSE selected for a shuttle flight, representing a cadre of military engineers picked specifically to fly alongside classified payloads. Some sources speculated that the inclusion of MSEs among NASA crews was to prevent them gaining too much knowledge about the secret satellites. But in a NASA oral history, Loren Shriver did not see it that way. “Gary had a specific purpose, but I don’t think it was to make sure that we didn’t learn about what the details of the mission were,” he remembered. “As a matter of fact, we all got briefed into the mission and we knew exactly what was going on.”



In one of relatively few images ever publicly released from Mission 51C, astronauts Loren Shriver (bottom), Ellison Onizuka (left) and Jim Buchli pose for a photograph in Discovery’s flight deck. Photo Credit: NASA

Deployment of the payload was executed under the watchful eye of Ellison Onizuka, who would sadly lost his life aboard Challenger on another IUS flight a year later. In a pre-flight interview for tragic Mission 51L, he related that he was “very familiar” and “very comfortable” with the IUS, indicating perhaps that its earlier performance issues had been resolved by the time 51C flew.

Discovery landed at KSC at 4:23 p.m. EST on 27 January 1985, after only three days in space; with the exception of the first two shuttle test flights, this was the reusable spacecraft’s shortest-ever operational voyage. But with the return of 51C’s boosters, a worrying story began to emerge. Critical O-ring seals, whose purpose was to prevent heated gases from emerging through the boosters’ field joints, were colder on 51C than any previous shuttle launch. As the Rogers Commission investigators would demonstrate a year later, cold temperatures impaired the performance of both the primary and secondary O-rings. As outlined in Chapter Six of the Rogers report, 51C’s left-hand and right-hand SRB nozzle joints both exhibited evidence of “blow-by” between their primary and secondary O-rings. “Blow-by erosion happens when the O-ring has not yet sealed the joint gap,” it was noted, “and the edge of the ring erodes as the hot gas flows around it.”

In their summary of the 51C event, the Rogers investigators laid bare the severity of the damage. “The primary O-ring in the left booster’s forward field joint was eroded and had blow-by, or soot behind the ring,” it was reported. “The right booster’s damage was in the center field joint: the first time that field joint seal was damaged. Both its primary and secondary O-rings were affected by heat and the primary ring also had evidence of blow-by of soot behind it. This was also the first flight where a secondary O-ring showed the effect of heat.” O-ring damage had been seen on earlier shuttle missions, but according to engineer Roger Boisjoly in his Rogers testimony, this was the first actual penetration of a primary O-ring on a field joint with hot gas. “The grease between the O-rings was blackened, like coal,” he testified, “and that was so much more significant than had ever been seen before on any blow-by on any joint.”

A few days after 51C’s landing, on 31 January 1985, SRB Project Manager Lawrence Mulloy of NASA’s Marshall Space Flight Center (MSFC) in Huntsville, Ala., recommended that the forthcoming Flight Readiness Review (FRR) for Mission 51E—the next-scheduled shuttle flight, then planned for February—should “recap all incidents of O-ring erosion, whether nozzle or case joint, and all incidents where there is evidence of flow past the primary O-ring”. Booster manufacturer Morton Thiokol of Brigham City, Utah, responded that “the condition is not desirable, but is acceptable”. Perhaps one of the greatest tragedies of Mission 51C is that Ellison Onizuka would also be aboard Challenger’s final flight, a year later, in which O-ring failure would stop the fleet in its tracks and the shuttle program’s veneer of invincibility would never be the same again.


Source: https://www.americaspace.com/2020/01/26/remembering-shuttle-discoverys-miracle-mission-51c-35-years-on-part-2/#more-110789
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Odp: [AS] Remembering Shuttle Discovery's Miracle Mission, 35 Years On
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