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'Making Superman Jealous': 15 Years Since the First Female Shuttle Commander (Part 1) (1)
By Ben Evans, on July 26th, 2014

Eileen Collins, the first female spacecraft commander in history, floats in Columbia’s middeck, 15 years ago this week. Photo Credit: NASA

“It’s great to be back in zero-g again,” said STS-93 commander Eileen Collins, early on 23 July 1999, as she and her four crewmates set about preparing the Shuttle Columbia for five days of orbital activities, but added darkly that “a few things to work on ascent kept it interesting.” Those things, within seconds of liftoff, almost forced Collins—the first woman to command a space mission, 15 years ago, this week—to perform a hair-raising abort landing back at the Shuttle Landing Facility (SLF) at the Kennedy Space Center (KSC), and the incident effectively grounded the shuttle fleet for almost six months.

Columbia’s flight was a long time coming. More than a year had elapsed since her last mission, but the cause of the delay had nothing to do with NASA’s venerable old workhorse herself. Originally scheduled for launch in August 1998, it was postponed until December, then January 1999, then April, and ultimately midsummer, by a chain of technical problems with STS-93’s primary payload, the $1.5 billion Chandra X-ray Observatory and the Boeing-built Inertial Upper Stage (IUS) which would propel it into an unusual orbit. Columbia—the oldest member of the fleet of shuttle orbiters and the only one not yet to have been modified with an International Space Station (ISS)-specification airlock and docking mechanism in her payload bay—was ideally tasked to deliver Chandra into space.

The reason for this was Chandra’s sheet size. When affixed to the IUS and mounted on a supporting “tilt table,” the observatory consumed 57 feet (17.4 meters) of Columbia’s 60-foot-long (18.3-meter) payload bay and weighed more than 49,800 pounds (22,600 kg). In anticipation of their back-to-back ISS flights, the other three orbiters had already had their internal airlocks removed from the middeck and replaced inside the docking mechanism in the forward quarter of their payload bays. The result was that there was not enough room in the bays of Discovery, Atlantis, or Endeavour to house Chandra. Yet even Columbia herself had to lose 7,000 pounds (3,200 kg) of additional mass before she could transport the new observatory aloft. To achieve some of these savings, engineers used older, lighter main engines, which lacked the newer and more rugged high-speed fuel pumps and combustion chambers. “We put Columbia on a strict diet to get to this mission,” said processing manager Grant Cates. “That work actually began [in 1996] with the identification of this mission and the weight reduction that would be required.” Nonetheless, the orbiter’s weight would still creep above NASA’s normal safety limit in the event that an emergency landing was required, shortly after launch.

The sheer size of the Chandra X-ray Observatory is amply illustrated in this perspective of Columbia’s open payload bay. Photo Credit: NASA

In such an eventuality, Columbia would tip the scales at 249,000 pounds (113,000 kg), some 1,300 pounds (590 kg) heavier than safety rules mandated as the maximum allowable landing weight. In the case of STS-93, a one-time-only waiver was granted to this rule, based on a detailed analysis of the payload, the shuttle’s center-of-gravity constraints, and a host of interrelated factors. For Eileen Collins, the challenge of possibly having to perform a heavier-than-normal emergency landing, known as a Return to Launch Site (RTLS), did not faze her. “We would land at 205 knots, which is very close to the maximum certification around 214,” she explained in a pre-launch interview. “There are some challenges there, but I feel very confident we’ve looked at the abort landings and they’re well within the safe limits of landing the shuttle.”

Collins’ confidence in her abilities and those of her crew would come close to being tested. Joining her and “rookie” pilot Jeff Ashby were mission specialists Catherine “Cady” Coleman, Steve Hawley, and Frenchman Michel Tognini. In November 1997, Tognini became the first member of the STS-93 crew to be announced by NASA and was joined by Collins, Ashby, Coleman, and Hawley in March 1998. “I was very happy because I had been waiting for such a long time to get this assignment,” Tognini told a NASA interviewer. “At one point, I was expected to have a flight on shuttle-Mir, because I spoke Russian and I flew previously on Mir and Soyuz. Instead of flying to Mir, they asked me not only to fly on STS-93, but to also be in charge of the deployment of Chandra with Cady Coleman. I was very surprised and proud to have such a challenge and such responsibility.”

Making his fifth shuttle, Steve Hawley had been newly appointed as deputy director of the Flight Crew Operations Directorate at the Johnson Space Center (JSC) in Houston, Texas, when he was approached to join the STS-93 crew. “I think they were looking for an experienced person for that mission,” he told the NASA oral historian. “It was a relatively junior crew. I think they were looking for somebody experienced to add to the mix of relatively less experienced people.” When he was first asked, Hawley declined the invitation to join the crew, having only recently flown aboard the STS-82 Hubble Space Telescope servicing mission. “I thought I really hadn’t been back in my real job that long yet,” he explained to the oral historian, “and I didn’t think that it was appropriate for me to step aside and fly again that soon, but they pestered me and so I did it, but I honestly told them that I didn’t think it was the right thing to do.”

In many ways, STS-93 harked back to the early days of the shuttle program. Not only would it last just five days—making it NASA’s shortest planned mission for almost eight years—but it would also feature the deployment of the orbiter’s final IUS payload. Built by Boeing and provided by the U.S. Air Force, the IUS had originally been developed as a short-term stand-in for a reusable “space tug” and was initially dubbed the “Interim Upper Stage,” before changing to “Inertial” in recognition of its sophisticated internal guidance system. Its first shuttle use on STS-6 in April 1983 put a key NASA communications satellite into a lower-than-planned orbit. This failure led to several missions being postponed, but the IUS eventually established itself as an exceptionally reliable booster.

However, it was still prone to difficulties. On 9 April 1999, a Titan IV rocket carried a Defense Support Program (DSP) missile early-warning satellite aloft, but both the first and second stages of the IUS failed to separate properly and the $250 million payload was lost. Ordinarily, NASA would have watched the resulting investigation with interest and incorporated its findings into its own plans to ready Chandra’s IUS for launch. This was complicated, however, by the fact that the investigation itself was classified. Moreover, said Scott Higginbotham, who oversaw Chandra’s pre-flight processing at KSC, the IUS assigned to STS-93 was impounded as part of the investigation. Original plans had called for it to be attached to Chandra on 23 April, but this was delayed as investigators set to work. Columbia’s launch, then scheduled for 9 July, came under review and the impounded IUS had a domino-like effect on the training of the astronauts and their ground teams.

The Boeing-built Inertial Upper Stage (IUS) is here pictured at the base of a NASA Tracking and Data Relay Satellite (TDRS) on an early shuttle mission. Photo Credit: NASA

“We were planning a two-day-long sim, starting 14 April, that would involve all the different control centers, a joint integrated simulation, with everybody,” explained STS-93 Lead Flight Director Bryan Austin. “That was going to be a big deal. That has been postponed because the Air Force folks and Boeing IUS people were going to be taken away initially to be part of the investigation. That exercise has been put on hold. That kind of put a wrench in things in terms of our sim schedule.”

The launch of Chandra was also significant because it was the shuttle’s first IUS mission since STS-70 in July 1995, and, according to Austin, “there has been a lot of change in the expertise level, collectively. For the most part, IUS deployment procedures are the same, but something that, to me, has been a struggle for this flight with some of our IUS friends is to get them to realize that the payload on the other end of the IUS is not the typical thing that the shuttle has been doing.” His point was that, as soon as the Chandra/IUS combo transitioned to internal battery power, just minutes before deployment, the observatory would be on its own. On previous missions, if something went awry at the last moment, the IUS and its payload could be retracted for another attempt or returned to Earth. In the case of Chandra, power and temperature constraints meant that mission managers had just a single shot at a deployment. “It’s either going to become orbiting space trash,” said Austin, grimly, “or it’s going to go out and do its mission.”

In fact, Chandra was the third in a quartet of “Great Observatories” which NASA had been planning for more than two decades to explore the Universe with sensors that jointly covered virtually the entire electromagnetic spectrum. The first two observatories—Hubble, launched in April 1990, and the Compton Gamma Ray Observatory, which followed in April 1991—focused on visible and ultraviolet wavelengths, as well as high-energy gamma radiation. Two others would then cover X-rays (Chandra) and infrared (the 2003-launched Spitzer Space Telescope). “Hubble revealed the visible side of the Universe,” said theorist Michael Turner of the University of Chicago in Chicago, Ill., “but most of the Universe does not emit visible light. It’s only visible by other means, in particular the X-rays. Chandra will give us the same clarity of vision as Hubble does, but for the ‘dark’ side of the Universe we know the least about.” Comparing astronomers’ capabilities before and after Chandra, astronaut Steve Hawley likened it to the difference between the small reflecting telescope he had used as a child and the enormous observatory on Mount Palomar in San Diego, Calif.

“We can make Superman jealous with our X-ray vision!” claimed Ken Ledbetter, NASA’s head of mission development for Chandra. The observatory, which received Congressional approval in 1987, used the most precisely figured X-ray mirrors ever built. It was hoped to equal, or even surpass, Hubble by studying some of the most exotic phenomena in the known Universe, including quasars, black holes, and white dwarfs. The spacecraft was a tapering cylinder, 45.3 feet (13.8 meters) in length, with two solar arrays at its base to provide electrical power. At the opposite end, mounted in the telescope’s primary focus, were its two scientific instruments: the High Resolution Camera and the CCD Imaging Spectrometer. Chandra’s concentric nest of cylindrical mirrors were coated with reflective iridium and gave it ten times the resolution of existing X-ray detectors and 50 times the sensitivity.

Of the many astronomical targets for Chandra, black holes were sure to seize the public’s interest, even though so little was known about them. By definition, they are “unobservable,” but the capability existed to indirectly study them by analysing radiation emitted by material being sucked into them. As interstellar gas and dust is accelerated, for example, it collides with increased energy levels and emits X-rays before vanishing across the “event horizon.” By examining such emissions in unprecedented detail with Chandra, astrophysicists hoped to identify black hole signatures. Additionally, supernova explosions thought to lead to black holes were placed under scrutiny. One of the observatory’s first celestial targets was the remnant of a massive star in the Large Magellanic Cloud that was seen to explode in 1989. On a far larger scale, it was anticipated that Chandra would focus on the amount of dark matter present in the Universe, by carefully examining galactic clusters. Such galaxies which make up these clusters are deeply embedded in huge clouds of hot, X-ray-emitting gas and are held in place by gravity generated by all the components of the cluster. Its observations were thus expected to enable astrophysicists to refine their numbers of how much “normal” matter is present in a given cluster and thus how much “dark” matter must also be present in order to generate gravity needed to hold it together.

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'Making Superman Jealous': 15 Years Since the First Female Shuttle Commander (Part 1) (2)

Chandra, one of NASA’s “Great Observatories,” has been operating in space since 1999. Chandra detects and images X-ray sources that lie within our Solar System to those billions of light-years away. The results from Chandra help explore high-energy phenomena and provide insights into the Universe’s structure and evolution. Image Credit: NASA/CXC/NGST

Chandra was originally conceived in the 1970s, when NASA envisaged a Large Orbiting X-ray Telescope. That was later de-scoped and became the HEAO-2 Einstein Observatory, whose success prompted the space agency to include an X-ray telescope on its wish list for a four-spacecraft flotilla of Great Observatories. Early plans called for it to be launched into low-Earth orbit and periodically serviced by shuttle spacewalkers for a projected 15-year lifespan, but in 1991 escalating costs and technical problems forced a rethink of the mission. It was effectively split into two halves. One half would transport a high-resolution camera and imaging spectrometer into a highly elliptical orbit, which, although beyond the reach of the shuttle, would enable it to gather data from 55 hours of each 64-hour orbit. Meanwhile, the second half would be equipped with a super-cooled X-ray spectrometer and would be launched into a lower orbit, but was cancelled by NASA in 1993 in another round of budget cuts. Even with the cancellation of the second mission, Chandra—known at the time as the Advanced X-ray Astrophysics Facility (AXAF)—was still expected to cost $3 billion during its first eight years of operations, including the spacecraft itself, the shuttle and IUS launch costs, annual mission control and data analysis fees, use of the Tracking and Data Relay Satellite System (TDRSS), and a one-time charge to test the mirrors at NASA’s X-ray Calibration Facility (XRCF) at the Marshall Space Flight Center in Huntsville, Ala.

Nevertheless, even this cost was far cheaper than the $7 billion envisaged for an all-in-one AXAF in low-Earth orbit. The observatory’s two largest mirrors—each measuring 48 inches (122 cm) in diameter—for its High Resolution Mirror Assembly were completed in June 1991 and tested at the XRCF in September of the same year. By January 1995, all eight nested mirrors had been completed, polished, and measured. “The first mirror took nine lengthy polishing cycles to complete,” said AXAF Telescope Project Manager John Humphreys. “We then applied a process of continual improvements to get the job done much faster and were able to complete the final mirror in only three polishing cycles.” The reflective chromium-iridium coating was applied in May 1996.

The decision to launch Chandra into a location far from shuttle repair crews was a tough sell, particularly in the wake of Hubble’s spherical aberration problems in the early 1990s. Still, the highly elliptical orbit, ranging between 6,200 miles (10,000 km) and 87,000 miles (140,000 km) from Earth, offered several advantages. It was thermally benign, eliminating the problematic cycle of light-to-dark and warm-to-cold, every 90 minutes, and thus removed the problem of temperature cycling, which tended to wear out electrical and mechanical subsystems. Additionally, the observatory would spend 85 percent of its time above Earth’s radiation belts, allowing it a large, uninterrupted portion of each orbit for celestial observations and avoiding interference from energetic particles which might otherwise overwhelm its sensitive instruments.

As with the other Great Observatories, it was always intended that Chandra would be named after an eminent astrophysicist, whose research had helped to pave the way for the work it would perform. Chandra honoured the Indian-born scientist Subramanyan Chandrasekhar (1910-1995), affectively nicknamed “Chandra,” who has been widely labeled as the father of modern astrophysics. A Nobel Prize winner for his contributions to astronomy, he also conducted valuable theoretical work on stellar evolution that established a basis for the existence of neutron stars and black holes—the very objects that his mechanised namesake would observe from its high orbit. “Chandra thought black holes were the most beautiful things in the Universe,” said Lalitha Chandrasekhar, his 88-year-old widow, who attended the observatory’s launch on STS-93. “I hear a lot of people say they are bizarre, they are exotic, but to Chandra they were just beautiful.”

Jeff Ashby and Cady Coleman train with a high-definition camcorder in readiness for their tasks on STS-93. Photo Credit: NASA

It was not, however, only the redesign of the observatory and the troublesome IUS which kept the mechanized Chandra on the ground, but also technical glitches with the spacecraft itself. Problems completing its construction at prime contractor TRW’s Redondo Beach, Calif., facility had pushed the launch date from August to December 1998, then January 1999, and ultimately April owing to a number of computer software errors. On 20 January, only days before the spacecraft was due to be shipped from California to Florida, NASA announced yet another delay, caused by the need for TRW to evaluate and correct a potential problem with several printed circuit boards in the command and data-management system. A number of other, TRW-built satellites had turned up faulty copper circuitry, and, fully aware of Chandra’s high-priority status and the fact that its orbit would render it irreparable, the decision was taken to remove and replace the boards.

Although the replacement process delayed the spacecraft’s delivery to Florida by only a matter of days, it pushed STS-93’s launch back by five weeks to late May 1999, due to the requirement to conduct lengthy tests at KSC. This target, however, conflicted with shuttle mission STS-96, the first ISS docking flight, and the decision was taken to postpone STS-93 until early July. Then, with only two weeks to go, Chandra engineers were alerted to yet another problem, this time with 20 electrical capacitors.

Fortunately, these were cleared for flight, but it offered another heart-stopping moment in the observatory’s tumultuous development. The heart-stopping moments would not end there. Before Chandra made it to orbit, STS-93 would endure one of the most hair-raising launches in shuttle history.


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'Whatever Was Needed': 15 Years Since the First Female Shuttle Commander (Part 2) (1)
By Ben Evans, on July 27th, 2014 [AmericaSpace]

Columbia roars into the darkened Florida sky at 12:31 a.m. EDT on 23 July 1999. It would be one of the most hazardous launch phases in shuttle history. Photo Credit: NASA

Fifteen years ago, this week, the first woman ever to lead a space mission was launched aboard Shuttle Columbia to deliver NASA’s $1.5 billion Chandra X-ray Observatory—the third of a quartet of “Great Observatories” to observe the Universe across most of the electromagnetic spectrum—into a highly elliptical orbit. As described in yesterday’s AmericaSpace history article, the demands of Eileen Collins’ STS-93 mission were fraught with risk; risk which she and her crewmates, Jeff Ashby, Catherine “Cady” Coleman, Steve Hawley, and Frenchman Michel Tognini, were keenly aware of. However, as their July 1999 liftoff drew nearer, they intuitively knew that rising from Earth into orbit was arguably the most hazardous journey of any mission. Not until they actually began that journey, however, would they truly realize how hazardous it really was. 

Already long-delayed, Columbia’s launch was twice postponed before the STS-93 crew finally made it into space. On 20 July, the countdown was halted at T-7 seconds, when high concentrations of hydrogen gas were detected in the shuttle’s aft compartment. It was a particularly dangerous moment, coming milliseconds before the ignition of the three main engines. If the halt had been called after ignition, the result would have been a risky on-the-pad abort and probably a month-long delay in readying the vehicle for another attempt. The cause of the problem seemed to be a hydrogen “spike,” which a sharp-eyed launch controller spotted briefly peaking at 640 parts per million, or double the maximum allowable “safe” limit. During the crisis, the mood in the Launch Control Center (LCC) at the Kennedy Space Center (KSC) was tense, as indicated by voices on the communications loop. Sixteen seconds before launch, it seemed, one of two gas detection systems indicated the 640 ppm hydrogen concentration, and, even though the second device showed a more normal level of 110-115 ppm, launch controller Ozzie Fish radioed his colleague, Barbara Kennedy, at the Ground Launch Sequencer (GLS) console to manually stop the countdown. To the assembled spectators at KSC listening to spokesman Bruce Buckingham’s commentary, all seemed normal at first.

“T minus 15 seconds,” announced Buckingham, then “T minus 12 … 10 … nine … ”

Inside the Launch Control Center, Fish urgently radioed: “GLS, give cutoff.”

“ … eight, seven … ” continued Buckingham.

“Cutoff. Give cutoff!” interjected NASA Test Director Doug Lyons.

“Cutoff is given,” replied Kennedy at the GLS console.

“We have hydrogen in the aft [compartment],” Fish reported, “at 640 ppm.”

By now past what would have been a “normal” ignition of the main engines, Buckingham announced the disappointing news to the public. Back in the LCC, with hydrogen concentrations decreasing back toward normal levels, Lyons polled his team, asking them if any emergency safing procedures were needed, such as evacuating the crew from the shuttle, and was told that this was unnecessary. Within 10 seconds of the call for cutoff, the indication of high hydrogen levels had dropped to 115 ppm. Engineers would later blame the problem on faulty instrumentation and flawed telemetry. Although disappointing, the abort had, at least indirectly, shown that NASA was not making special provisions to get STS-93 away on time for the sake of several high-level spectators in the audience.

Led by commander Eileen Collins, the STS-93 crew emerges into the glare of television lights on the night of 22 July 1999. Photo Credit: Joachim Becker/

Eileen Collins’ presence on the crew, as the first woman ever to command a space mission, had dominated the news. Sitting in the VIP area at KSC was none other than First Lady Hillary Clinton, her daughter Chelsea, and representatives of the United States’ women’s football team. Clinton had formally announced Collins’ assignment to command STS-93 in March 1998 at a press conference in the Roosevelt Room at the White House. For Collins herself, the assignment was representative of having worked her way through the ranks, just like the male shuttle pilots, but for Clinton it was a public relations boon. In fact, some observers remarked that the naming of a shuttle commander from the White House was rare, if not unprecedented.

“Eileen’s just trying to do her job,” said Collins’ crewmate Cady Coleman in a pre-flight interview. “At the same time, I’m actually very excited about the historical significance—not for Eileen, not for me, but for the little girls out there. It’s really bringing home the fact to them that Eileen can do what she has set out to do. If all of us can become astronauts, it will help them to realize that the world can be theirs.” Steve Hawley, who sat on the astronaut selection board in late 1989, which ultimately picked Collins for training, remembered that it was obvious back then that she would possibly become the first female shuttle commander. “All of us that were part of that decision,” he said, “take pleasure in seeing it happen. As Eileen said herself, I think another opportunity is clearly available to young girls growing up.” Added pilot Jeff Ashby, who was making his first shuttle flight on STS-93: “Eileen has made me feel very comfortable and treated me not like a rookie, but as somebody who has flown before and I respect her for that.” For Michel Tognini, the wind of change carried even greater significance. When he began his French Air Force career, his superiors doubted that women could even fly aircraft. “Just recently,” he told a NASA interviewer in mid-1999, “I saw in the French Air Force newspaper that we have the first female French fighter pilot, even though we said 30 years ago that it would never happen. Never say never.”

Collins likened her leadership style to the flavor of a family. “It was important for me as a commander to learn what their talents and interests were,” she said of her crew. “With that, we were able to decide who would do what duties on the flight, keeping in mind that we would be able to change that later, if we found that we needed to spread the workload around a little bit better. As we started working eight to 16-hour days together, we really started to become a family. We got to know each other so well that we became like brothers and sisters. That’s one of the strengths I see in my crew. We listen to each other, we get along well, we really understand and can focus on the mission and when we make decisions for the mission, we do what would make it most successful. One thing that comes to mind is how we work together when we do simulations and we’re given malfunctions. You really get to see how people work under stress and you really get to know each other that way. That’s why it’s so important to train together. You need to know each other really well when you go up on a mission like this one.”

Yet the issue of being the first woman to command a space mission was not lost on Collins. Nor did she forget the other female giants, upon whose shoulders she stood. “I wouldn’t be sitting here today if it weren’t for all the people who’ve gone before me and set the stage to bring women into aviation,” she explained before the launch. “In the beginning of the century, it took a lot of courage to fly as a woman, when that really wasn’t a woman’s place. During World War II, there were the Women Air Force Service Pilots and the women who ferried aircraft. In the late 1950s and early 1960s, women competed to be astronauts. In the later 1960s, we started getting more women in the military. In the 1970s, women were offered the opportunity to fly in the military, active duty. That’s when I first became interested in flying. We had our first women selected as astronauts in 1978. Since then, we’ve had more and more women become astronauts. There are three women shuttle pilots now, including me.”

Backdropped by the stunning vista of Earth, the Chandra X-ray Observatory departs Columbia to begin its voyage of exploration. Photo Credit: NASA

The 20 July launch scrub demonstrated that NASA was unwilling to compromise safety to get Columbia off the ground, even with the First Lady in attendance. Fortunately, the fact that the main engines had not ignited meant that another attempt could be made on the 22nd. A third opportunity was also available on the 23rd, but after that a three-week delay until mid-August would be unavoidable, because the U.S. Air Force had scheduled a major upgrade of its tracking assets on the Eastern Range. In eager anticipation of another attempt on 22 July, eight middeck payloads were removed and serviced and hydrogen sensors in the aft compartment were recalibrated. Additionally, the hydrogen igniters—the system that cleared unburned hydrogen from beneath the engines, ahead of ignition—was replaced. The second effort to get STS-93 airborne also seemed afflicted by misfortune when lightning strikes were recorded, just 3 miles (5 km) from the launch pad. According to flight rules, no lightning was permitted within a radius of 7.5 miles (12 km). The countdown was held at T-5 minutes, in the hope that conditions might improve, but when they failed to do so, the attempt was scrubbed.

“Eileen, we gave it our best shot with this storm today,” said Doug Lyons, “but it didn’t agree with us, so our best bet is to give it another try another day.”

“Okay, CDR copies,” replied Collins, “and we though you guys did a great job tonight. We’re proud of the work and the crew will be ready to go at the next opportunity.”

NASA managed to convince Boeing to postpone a scheduled Delta II launch from nearby Cape Canaveral Air Force Station in order to give STS-93 another opportunity on 23 July. A safe launch was paramount, and former astronaut Don McMonagle, then serving as head of the Mission Management Team, noted that STS-93 would slip until 18 August if this third attempt was scrubbed. In the late evening of 22 July, Collins and her crewmates clambered back aboard Columbia. Right on time, and true to form, Columbia sprang from Pad 39B at 12:31 a.m. EDT on the 23rd, turning night into day across the marshy Florida landscape.

However, the commentator’s excitement-tinged announcement—“We have ignition and liftoff of Columbia, reaching new heights for women and X-ray astronomy”—masked a serious problem brewing in the shuttle’s main engines. It came to the attention of Collins and Ashby five seconds after leaving the pad, when they noted a voltage drop on one of the electrical buses. This caused one of two backup controllers on two of the three engines to abruptly shut down. The third engine was unaffected by the problem, and, luckily, all three performed nominally, boosting Columbia into a 155-mile (250 km) orbit, inclined 28.45 degrees to the equator. Nonetheless, the scare was significant. On no other mission had a shuttle crew come so close to having to perform a Return to Launch Site (RTLS) abort landing. Had the primary controllers, which immediately assumed critical command, also failed, an engine failure was likely and that would have required Collins to wait for the separation of the twin Solid Rocket Boosters (SRBs), flip Columbia over, fly “backwards” at 10 times the speed of sound in order to bleed off speed, then head back west, jettison the External Tank (ET), and guide the orbiter down to the Shuttle Landing Facility (SLF) runway … all under the cloak of darkness.

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'Whatever Was Needed': 15 Years Since the First Female Shuttle Commander (Part 2) (2)

Attached to its Boeing-built Inertial Upper Stage (IUS), the Chandra X-ray Observatory disappears into the inky darkness of space after deployment from Columbia. Photo Credit: NASA

“We were prepared for that,” she said later. “We were listening for the engine performance data calls [from Mission Control] on ascent. This crew would have been ready to do whatever was needed.” Fortunately, Columbia made it safely into space, but was travelling at 14.8 feet per second (4.5 meters/sec) slower than expected. Although this discrepancy was tiny in view of her 17,400 mph (28,000 km/h) orbital velocity, it was enough for puzzled engineers to question whether there might have been a 4,000-pound (1,800 kg) shortfall in the liquid oxygen pumped into the ET before liftoff. NASA confirmed on 24 July that the loading of propellants had been done correctly, although it would become part of the investigation into the electrical short. Analysis of still video imagery during the STS-93 ascent also revealed another problem: a leak of hydrogen gas from one of the main engines. The images, particularly those from cameras mounted on Pad 39B, revealed a narrow, bright area inside the nozzle of the right-hand engine, possibly indicative of a weld-seam breach in one of more than 1,000 stainless steel hydrogen recirculation tubes. Although Wayne Hale, then serving as Columbia’s Mission Operations Director, stressed that few conclusions could be made until the engine was back on Earth, he speculated that the leak might explain the “missing” liquid oxygen. As hydrogen was lost at a rate of 2.2 pounds (1 kg) per second, the main engine controllers compensated by guzzling oxygen at a higher rate.

It had been one of the most hazardous ascents in shuttle history and would lead directly to the grounding of the rest of the fleet for the next six months. For Eileen Collins’ crew, savoring their inaugural moments of weightlessness, their immediate business was getting the Chandra X-ray Observatory primed for deployment. The first few hours were spent checking the health of both Chandra and its Inertial Upper Stage (IUS) booster, primarily under the direction of Coleman and Tognini, before the stack was tilted up to its deployment angle of 58 degrees. “Michel and I work as a team,” Coleman explained before launch. “I put my finger on a switch, he verifies it’s the right switch and that is very, very helpful to me. We also have a third person in the background—Steve Hawley—whose job is the big picture of the deploy. It’s very human to make a mistake and we cannot afford that, so we’re doing everything we can to prevent that.” Interestingly, assignment to STS-93 was not Coleman’s first involvement with Chandra. Earlier, she had met the team which ground the mirrors for the telescope and presented them with a NASA award. “I also visited Kodak, where they assembled the entire telescope,” she said. “This was new for me, to learn about this amazing telescope that was going to be launched. Suddenly, I was assigned to the mission and I thought, “You know, I’m supposed to do this!””

If the crew had missed their first deployment “window,” matters would have become complicated. “If we have to keep [the payload] in the bay overnight, it really constrains things,” said STS-93 Lead Flight Director Bryan Austin. “If they lose any power to the heaters that keep the [propellant] lines from freezing, it really gets dicey in terms of being able to still possibly support a mission, because we cannot put them in a warm-enough attitude to keep everything warm without hurting [Chandra].” Thankfully, all went well on the first attempt. After a critical, “Go/No-Go” decision by flight controllers at the Johnson Space Center (JSC) in Houston, Texas, and at the Chandra Operations Control Center in Cambridge, Mass., the IUS was transferred to its own batteries for power and cables routing electricity to the spacecraft were severed. At 7:47 a.m. EDT on 23 July, seven hours and 16 minutes into the mission, as Columbia flew high above Indonesia, Coleman commanded the Chandra-IUS stack to be spring-ejected from its cradle in the payload bay. The deployment occurred precisely on time, at the opening of a “window” that ran for barely eight minutes and 45 seconds.

“Houston, we have a good deploy,” reported Collins. “Chandra is ready to open the eyes of X-ray astronomy to the world.”

In spite of the focus of the Chandra X-ray Observatory on the Universe, the focus of the STS-93 crew remained the Home Planet, as highlighted in this glorious image of Earth. Photo Credit: Joachim Becker/

After the mission, Coleman told an interviewer that she was so taken aback by the beauty of the observatory disappearing into the inky blackness that she was rendered “almost too excited to video.” Shortly after deployment, Collins and Ashby maneuvered Columbia into a “window-protection” orientation, with the orbiter’s belly pointed toward the IUS nozzle. An hour later, at 8:47 a.m., with the shuttle about 30 miles (50 km) “behind” the stack, the first-stage engine of the IUS ignited for just over two minutes. Approximately 60 seconds after the completion of its “burn,” the first stage separated and the second stage took control and performed its own burn for another two minutes. The booster’s next task was to keep Chandra properly oriented as its twin solar arrays unfurled. Shortly before the separation of the second stage, and after insertion into a preliminary elliptical orbit, at 9:22 a.m. EDT, Chandra’s solar arrays were deployed with perfection. The separation of the second stage occurred without incident at 9:49 a.m. The IUS team was delighted with the performance of their booster.

By this point, the observatory was in an orbit with an apogee of almost 45,980 miles (74,000 km) and a perigee of 202 miles (325 km). This was adjusted by Chandra’s own thrusters over the following three weeks to achieve a final elliptical orbit with an apogee of 87,000 miles (140,000 km) and a perigee of 6,200 miles (10,000 km).

Another development was the discovery of what Wayne Hale called “our smoking gun” for the mishap during ascent. Collins found a tripped circuit breaker in the cockpit for the center main engine controller. Its discovery persuaded mission managers that the controller of the engine, or at least its wiring, had been responsible for the electrical short.

Following five days in orbit, Collins fired the shuttle’s Orbital Maneuvering System (OMS) engines as planned at 10:19 p.m. EDT on 27 July to commit Columbia to a descent back to Earth. Passing over Baja California and northwestern Mexico, the spacecraft bisected Texas from west to east, crossed southern Louisiana, and alighted onto the SLF Runway 33 at KSC in darkness at 11:20 p.m. EDT. Although a tremendous technical and scientific success—and ushering in a new era of X-ray astronomy—the mission had proven pivotal for women in aviation. Eight years later, in October 2007, Pam Melroy would become the second woman to command a shuttle, and in June 2013 NASA selected its latest group of astronaut candidates, two of whom are qualified test pilots and thus eligible for command positions on future space missions. Yet Eileen Collins was the trailblazer. In the aftermath of STS-93, the crew had nothing but praise for their commander. “I get asked a lot how it is to fly with Eileen,” said Jeff Ashby. “I think the women’s soccer team captain summed it up best: Eileen Rocks!”


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