[AS] In the Shadow of Challenger: The Lost Mission of STS-61E

[Orionid]

In the Shadow of Challenger: The Lost Mission of STS-61E (Part 1)
By Ben Evans, on March 9th, 2013


Had Challenger not been lost, these seven men were the next scheduled Shuttle crew. Seated from left to right are Pilot Dick Richards, Commander Jon McBride and Mission Specialist Dave Leestma, the 'orbiter' crew in charge of Shuttle systems. Standing from left to right are the 'science' crew: Payload Specialist Sam Durrance, Mission Specialists Bob Parker and Jeff Hoffman and Payload Specialist Ron Parise. Photo Credit: NASA

On the morning of Tuesday, 28 January 1986, as seven astronauts prepared to ride Challenger into orbit from Cape Canaveral, Fla., seven other astronauts climbed out of the Shuttle Mission Simulator at NASA’s Johnson Space Center in Houston, Texas, to watch the event on television. The men of Mission 61E knew that their own flight, barely five weeks hence, was time-critical, for it would make ultraviolet observations of Halley’s Comet, which was making its 75-yearly visit to the inner Solar System. Seventy-three seconds after Challenger broke the shackles of Earth and climbed for the heavens, she was catastrophically lost with all hands … and the men of 61E knew that their own mission was gone. Little could they have known that if Challenger had survived that day, there was an enormous likelihood that disaster may have befallen them instead. …

It has long been the subject of both idle and educated coffee-table gossip to consider what-if scenarios in the space program, and all astronauts were acutely aware that, no matter the precautions and safeguards, tragedy lurked behind ever corner. The shuttle was such a complex machine—with more than 800 “Criticality One” items, capable of causing Loss of Vehicle and Crew in the event of a failure—that it would be foolhardy to believe otherwise. Yet it was more than a mere check of the odds which seemed to load the dice against 61E. Years later, Mission Specialist Bob Parker told the NASA oral historian that the frigid weather conditions which contributed to Challenger’s doom were even colder on the night of 5/6 March 1986, when he and his crewmates should have launched aboard Columbia.

And if NASA’s shuttle manifest was to be believed, the night of 5/6 March was the date on which the new mission would set sail. It would have been a difficult target to meet, for Columbia had only returned from her previous flight, Mission 61C, in mid-January, leaving an astonishing six weeks to prepare the vehicle for space. (This is remarkable, when one considers that even in its heyday in the mid-1990s, flying a combined total of seven times each year, the individual orbiters required at least four months to process between missions.) Yet for Parker and his crewmates, getting 61E into space on time was not simply required, but virtually set in stone.

“We were preparing to fly in 40 days to observe Halley’s Comet,” remembered Parker. “Obviously we didn’t fly 40 days later!” Yet the bullish attitude of NASA management in the weeks and months leading up to the Challenger tragedy had different priorities … and those were governed almost exclusively by the need to meet launch schedules. The return of Halley’s Comet to the inner Solar System in late 1985 and early 1986 had already provoked a flurry of missions—the International Cometary Explorer (ICE), the European Giotto, the Soviet Vegas, and the Japanese Suisei and Sakigake—to explore the fabled celestial wanderer, and the shuttle was expected to carry cameras and telescopes on three separate missions to observe it.


When Columbia touched down at Edwards Air Force Base, Calif., on 18 January 1986, the heat was on to return her to the East Coast—normally a week-long process—and prepare her for another liftoff in the early hours of 6 March. It would have stretched the Shuttle Program’s resources to their limits. Photo Credit: NASA

Of these, 61E was the most important, for Columbia would carry a battery of ultraviolet telescopes, known as “ASTRO-1,” to observe the comet’s progress. In order to complete these observations at the most optimum time, Columbia had to launch early in March 1986. The criticality of this launch date had already been picked up by the press, and Flight International reported as early as December 1985 that the mission “must be launched by 10 March to achieve maximum science return,” warning that “a slip to 20 March would result in the flight’s cancellation.” By the time of the Challenger accident, 61E was scheduled to begin at 5:45 a.m. EST on the 6th. In the years that followed, Bob Parker would prove vocal in his astonishment at such definitive, immovable targets. “It’s amazing,” he said, “when you look back at that, and the rate at which we thought we had to keep pumping this stuff out.” Parker had an expression: The Sun kept rising and setting. Schedule pressure meant nothing in the face of crew safety.

Had Challenger not been lost that frigid January morning, Parker is almost certain that his own mission might have fallen victim to the technical and managerial cancers which riddled the shuttle at this time … for conditions in Florida in the early hours of 6 March were even colder, and the effect of cold weather on O-ring seals in the Solid Rocket Boosters was later identified as a key factor in the accident. It is almost certain that NASA would have pressed ahead with the 61E launch and, if Columbia made it to orbit safely, it promised to be one of the most exciting scientific missions to date. Although it will never be known if Columbia could have been ready in time, NASA was still aiming to launch 61E at 5:45 a.m. EST on the 6th, kicking off an ambitious flight, during which the seven-man crew would have worked in two 12-hour shifts to operate ASTRO-1 around the clock. The “red” team comprised Parker, Pilot Dick Richards, and Payload Specialist Sam Durrance, with Mission Specialists Dave Leestma and Jeff Hoffman and Payload Specialist Ron Parise on the “blue” team. Commander Jon McBride, meanwhile, would have anchored his schedule across both shifts.

When the Crew Activity Plan for 61E was published by NASA in November 1985, it was expected that the flight would run to almost nine days, making it the second-longest shuttle mission in history at that time. Landing was scheduled for 3:47 a.m. EST, 15 March. As the lead Mission Specialist, Jeff Hoffman had spent almost four years working on ASTRO-1. He had been approached by George Abbey, the head of Flight Crew Operations, in 1982 to follow the mission and determine if it was sufficiently complex to warrant a pair of Payload Specialists. Hoffman was vocal in his conviction that it was, but worried that NASA senior managers opposed the idea of astronauts selected and trained outside of the agency’s immediate jurisdiction. “We knew George Abbey didn’t like the idea of Payload Specialists,” Hoffman told the NASA oral historian, years later. “Was writing this report going to be career-limiting?” Abbey’s powerful ability to approve or veto astronaut selections was known to be immense, but Hoffman need not have worried: in June 1984, he and Bob Parker were formally announced as Mission Specialists and were later joined by Durrance and Parise, followed, in January 1985, by McBride, Richards, and Leestma.


Photographed on 8 March 1986 from Easter Island, as part of the International Halley Watch (IHW) Large Scale Phenomena Network, this view occurred at precisely the time the STS-61E should have been directing their ultraviolet telescopes toward the fabled celestial visitor. Photo Credit: NASA

The three ASTRO-1 instruments were the Hopkins Ultraviolet Telescope (HUT), the Ultraviolet Imaging Telescope (UIT), and the Wisconsin Ultraviolet Photopolarimeter Experiment (WUPPE), and all were attached to a device known as the Instrument Pointing System (IPS) in the shuttle’s payload bay, which would direct them toward their celestial targets. Organizational, technological, and schedule difficulties had mired the IPS development effort for more than a decade before it flew its first mission in July 1985, with generally favorable results. However, before Challenger, one senior ASTRO-1 manager told Flight International that if the IPS failed, “the whole mission is down the drain.” It was not an idle statement, for ASTRO-1 was actually the first of three missions to be flown at six-monthly intervals in 1986-87. And the jewel in the crown, dated and fated to behold Halley’s Comet in all its glory, was Mission 61E itself.

In the aftermath of Challenger, the entire crew was stood down, indefinitely. For Jeff Hoffman, the decision to stick around and wait for ASTRO-1 was an easy one to make, but other astronauts felt otherwise. At length, in November 1988, a new ASTRO-1 crew was formed from the remnants of 61E: Hoffman, Parker, Durrance, and Parise would fly aboard the redesignated STS-35, together with McBride in command, and two other astronauts, Guy Gardner as pilot and a third mission specialist, Mike Lounge. A few months later, in May 1989, McBride abruptly resigned his post to return to his native West Virginia, and NASA replaced him with veteran astronaut Vance Brand.


Pictured in 1990, during processing for its long-delayed mission, the ASTRO-1 payload was attached to an Instrument Pointing System (IPS), which would guide its telescopes to their targets. Photo Credit: NASA

In his NASA oral history, McBride rationalised his thinking. Shortly after his assignment to STS-35, rumors arose that ASTRO-1 was destined for cancellation. “My wife and I had bought a home in West Virginia, in the beautiful Greenbrier Valley,” he explained, “and I was commuting.” McBride saw his family every two or three weeks, until one morning something changed. “I looked out the back window and there were deer and pheasants and squirrels and rabbits,” he said, “and seeing the Greenbrier River and the snow-capped peaks … I [had] two choices. I can hang it up now and come back here to West Virginia … or I can go down to Houston and take a chance of training for two more years and never going anywhere.” By his own admission, the choice was tough, but at length McBride called Don Puddy, then head of Flight Crew Operations, with his decision. “I might be the only person in history who was assigned to a mission that pulled out of it,” he admitted. As circumstances transpired, ASTRO-1 did fly, but years later McBride felt that he made the right decision. In West Virginia, he established a venture capital company, bringing industry and jobs to the area, which he felt enabled him to make a positive impact and open up business opportunities.

In a sense, McBride’s fears for ASTRO-1 partially came true. Although the mission did fly, it also waited nearly two years, lifting off on 2 December 1990 … and that came after seven months of technical delays and maddening mechanical problems which grounded two-thirds of the shuttle fleet. As tomorrow’s article will reveal, getting ASTRO-1 ready to fly in the post-Challenger era was equally as difficult, if not more so, than it had been in the days leading up to the tragedy.

Source: https://www.americaspace.com/2013/03/09/in-the-shadow-of-challenger-the-lost-mission-of-sts-61e-part-1/

[Orionid]

In the Shadow of Challenger: The Found Mission of STS-35 (Part 2)
By Ben Evans, on March 10th, 2013


Pictured in September 1990, the problem-plagued STS-35/Columbia stack is shown in the foreground, on Pad 39A, with the STS-41/Discovery stack in the background on Pad 39B. Discovery would be the only orbiter to escape the disconnect crisis in the summer of 1990, but would succumb to her own problems the following year. Photo Credit: NASA

At the beginning of May 1990, the shuttle program was on its uppers. Four years since the catastrophic loss of Challenger and her crew of seven, the reusable fleet of orbiters had just completed their tenth post-51L mission by depositing NASA’s scientific showpiece—the $1.5 billion Hubble Space Telescope—into orbit. In less than three weeks’ time, another mission, STS-35, would roar aloft with a payload of ultraviolet telescopes to observe the Universe in unprecedented detail. ASTRO-1 had been long-delayed; it was supposed to fly in March 1986, as the next mission after Challenger, but had been delayed repeatedly. Those delays had even led to rumors that it would be canceled outright, and this informed Commander Jon McBride’s decision to resign from the mission. A year after McBride’s departure, with Vance Brand now in command, ASTRO-1 seemed ready to go. Columbia stood resplendent on Pad 39A at the Kennedy Space Center, Fla., with no problems being tracked … until the issue with the disconnects.

Deep inside the belly of the shuttle were a pair of 17-inch fuel lines, through which liquid oxygen and hydrogen flowed from the External Tank into the cluster of three main engines. Both “sides” possessed mechanical disconnect fixtures, and shortly before the separation of the External Tank, on the edge of space, a pair of flapper valves were commanded shut by pneumatic helium pressure to prevent further propellant discharge and contamination. The criticality of the disconnects and their flapper valves could not be underestimated; for any inadvertent closure whilst the main engines were firing would have prevented propellant flow from the External Tank and precipitated a catastrophic failure. In the days preceding the launch of STS-35, these disconnects took center stage in one of the most difficult engineering challenges ever faced by the shuttle program.


The 17-inch disconnect hardware is clearly visible, directly aft of the main landing gear doors, and was responsible for transferring liquid oxygen and hydrogen propellants from the External Tank to the shuttle’s three main engines. The volatility of these propellants meant that even the smallest of leaks could not be tolerated. Photo Credit: NASA

Before each mission, a Flight Readiness Review scrutinised all pertinent documentation, before formally reaching an agreement on a target launch date. At the beginning of May 1990, Columbia was provisionally scheduled to fly on the 16th, but a problem was noted with a proportioning valve on her Freon coolant loop, requiring its replacement. A second review was convened and settled on the 30th for launch. Then, during the lengthy process to load liquid hydrogen into the External Tank, a tiny leak was detected, close to the tail service mast on the Mobile Launch Platform. Further investigation revealed a much more extensive—and far more worrisome—leak, apparently coming from the disconnect hardware in Columbia’s belly. The launch attempt was called off and the External Tank was emptied and inerted. Since the crew would be working in two 12-hour teams in orbit, they had already begun “sleep-shifting,” and the “blue” team was awake when the news of the launch delay came through. Blue team member Jeff Hoffman recalled waking up his “red” team counterparts with the unwelcome news.

A few days later, on 6 June, a miniature “tanking test” was conducted to identify the exact location of the leak. It soon became clear that Pad 39A was not an appropriate place for exploratory work to be undertaken, and on the 12th the STS-35 stack was rolled back to the Vehicle Assembly Building (VAB). Columbia was removed from the stack and returned to the nearby Orbiter Processing Facility (OPF) for repairs on the 15th. Launch was rescheduled for mid-August. The shuttle “side” of the disconnect hardware was replaced with a set borrowed from the new orbiter, Endeavour, which was then undergoing final construction as Challenger’s replacement, and apparatus for the External Tank “side” arrived shortly thereafter from its assembly facility at Michoud in New Orleans. Jeff Hoffman remembered that it was a tough time on him and his crewmates. They were all fully trained, at the peak of mental and physical readiness, and yet were forced to sit through endless simulator sessions with no new launch date.

As this work was being undertaken, Atlantis progressed smoothly—or so it seemed—towards her own launch on STS-38 in July. As a precautionary measure, shortly after the STS-38 stack arrived at Pad 39A on 18 June, NASA decided to perform a tanking test on Atlantis to verify that she was not similarly affected. On the 29th, liquid hydrogen was pumped into her External Tank … and to engineers’ dismay the same problem appeared: after the fuelling process moved from “slow fill” to “fast fill,” concentrations of gas were found in the vicinity of her disconnect hardware. It was small and was described by NASA as “both temperature and flow-rate-dependent,” but the agency was convinced that the two leaks in Columbia and Atlantis represented nothing more than coincidence.

To identify the source, more instrumentation was fitted around the disconnect and a second tanking test was performed on 13 July. Sealants were added in a bid to stop the leak, but a third test on the 25th revealed that the problem persisted. Two weeks later, in the pre-dawn darkness of 9 August, the STS-38 stack rolled back to the VAB, providing a unique photo opportunity in the process, as the STS-35 stack passed it on its way back out to Pad 39A. Despite the similarities between the problems, NASA managers were convinced that the hydrogen leaks were unrelated. “Incorrect torqueing of bolts around the flange interface between the tank and the orbiter caused the Atlantis mishap,” Flight International told its readers on 8 August. “The Columbia leak was caused by a faulty seal in the drive mechanism used to close the flapper valve in the disconnect.”

STS-35 was rescheduled for launch on 1 September. Misfortune, though, was far from finished with the unlucky flight. Two days before launch, an avionics box on ASTRO-1 failed and required replacement, prompting a delay of several days. Then, on the evening of the 5th, technicians began to load propellants into Columbia’s External Tank … only to discover hydrogen gas again leaking into the aft compartment of the orbiter. The maximum allowable rate was 660 parts per million; but the actual rate of leakage was upwards of 6,500 ppm. …

It was now apparent that two separate leaks had evolved; the data indicated that the leakage from the disconnect was gone, but a new one had emerged, somewhere in Columbia’s aft engine compartment. A package of three hydrogen recirculation pumps in Columbia’s aft compartment were removed and replaced, together with a damaged Teflon seal on one of the main engines, but to no avail. In the hours preceding another launch attempt on 18 September, leaking gas was again detected, emerging at a rate of 6,700 ppm. STS-35 was indefinitely postponed until the leak was resolved. Space Shuttle Program Manager Bob Crippen assembled a “tiger team” to investigate the disconnects and totally “retorque” Columbia’s entire liquid hydrogen system.

Crippen assigned veteran engineer Bob Schwinghamer, from the Marshall Space Flight Center in Huntsville, Ala., to lead the investigation. In his NASA oral history, Schwinghamer remembered NASA Deputy Administrator J.R. Thompson telling him, without a hint of humour, that he had a one-way ticket to Florida; he was not to return to Alabama until the hydrogen leak was solved. Schwinghamer’s team spent three months at the Kennedy Space Center, setting up an intricate fault tree and co-ordinating across a huge number of personnel, spread across several NASA centers. By the time they completed the final tanking test on 30 October 1990, Schwinghamer could confidently declare that Columbia was now “the soundest leak-free orbiter at that time in the fleet.” The explosive nature of hydrogen meant that a leak of any sort could not be tolerated, and it certainly surprised Vance Brand, the commander of STS-35, that an orbiter was being grounded for such a long period. It marked a change in attitude from the way in which NASA management had worked before the Challenger accident.

The September 1990 delay was clearly remembered by Jeff Hoffman, many years later. Rather than risk having their children out of school for a lengthy spell, several of the crew decided to pay, personally, for air tickets from Houston to Florida and asked neighbours to take them to the airport. In the hours preceding the 18 September attempt, the Hoffman children—aged 11 and 15 at the time—were seated aboard the aircraft, with one engine in the process of starting up, when the Continental departures desk received a call from Hoffman himself. Another leak had emerged; there was no point in the children flying down to Florida. At the last possible moment, the engines fell quiet, the doors opened, and the disappointed children got off. Not until December would they see their father launch. By this time, the effort to fix the hydrogen leaks had cost NASA $3.8 million, and the agency suspected that Columbia’s problems originated from a complete disassembly of her main engines following the STS-32 mission in January 1990 to remove polishing grit from her fuel lines. When the engines were reassembled, the seals were imperfectly fitted and minute glass beads contaminated the disconnect hardware. From the beginning of June, the attention of engineers was drawn solely to the disconnect leak, which posed a more serious problem, and the seals were overlooked. “As a result,” explained Flight International in mid-November, “NASA has introduced a new processing programme in which key engine components will be checked for leaks before the engines are finally assembled.”


STS-35 finally lifts off, almost five years after ASTRO-1 should have been observing Halley’s Comet. Photo Credit: NASA

In late November 1990, NASA announced that a new hydrogen dispersion apparatus would be added to the Mobile Launch Platform for future missions, beginning with STS-39. The system would provide a nitrogen-rich air flow around the disconnect hardware, thus helping to disperse hydrogen concentrations. As for the disconnects themselves, NASA was already working on plans with Rockwell International to develop an upgraded system, somewhat narrower at 14 inches in diameter, and contracts worth upwards of $27.6 million were awarded in February 1991. It was expected that newer disconnect hardware would help to prevent inadvertent closure of the flapper doors during ascent, which threatened catastrophe. Ultimately, the new disconnect project was cancelled in 1993, but much of the technology behind it was employed to improve the safety and reliability of the existing 17-inch hardware. Furthermore, the space agency instituted more rigorous rules around the issue of hydrogen leakage, embedding them more firmly within its Launch Commit Criteria.

By 2 December 1990, the prophets of doom were noting that STS-35 would be the 13th post-Challenger mission—surely a portent of ill-fortune—but for the astronauts the impending launch after such a long wait came as a blessed relief. Jeff Hoffman knew that comets, like Halley, were supposed to bring bad luck, but by the end of 1990 there were no cometary targets for ASTRO-1 to observe. “We all know comets are harbingers of bad news,” Hoffman rationalised. “This time, we have no comet. So we’re going to go.”

And go they did. At 1:49 a.m. EST on the 2nd, Columbia rose gloriously into orbit on a mission which lit up the darkened Florida sky for hundreds of miles. The gremlins were not yet done with ASTRO-1, for the flight was plagued by technical difficulties and payload problems. However, the resurgence of this mission from the ashes of despair in the wake of Challenger, and its revival from the hydrogen leaks, makes it quite remarkable and an astonishing triumph over adversity.

Source: https://www.americaspace.com/2013/03/10/in-the-shadow-of-challenger-the-found-mission-of-sts-35-part-2/