'It's Gonna Be Great': 30 Years Since Shuttle Mission 51D (Part 1)

Spacewalkers Jeff Hoffman and Dave Griggs work to outfit a makeshift fly swatter onto the Remote Manipulator System (RMS) mechanical arm, in a fruitless attempt to activate Syncom 4-3's deploy switch. Photo Credit: NASA

Spacewalkers Jeff Hoffman and Dave Griggs work to outfit a makeshift fly swatter onto the Remote Manipulator System (RMS) mechanical arm, in a fruitless attempt to activate Syncom 4-3’s deploy switch. Photo Credit: NASA

None of the 135 missions flown by NASA’s five-strong fleet of shuttle orbiters between April 1981 and July 2011 could ever be classified as “routine” and all contributed greatly to our exploration of space. However, if there was one flight which actually proved a little more colorful than originally intended, it would be Mission 51D, the fourth voyage of Discovery, which launched 30 years ago, next week. As detailed in an earlier AmericaSpace history series, the flight originated as Mission 41F, targeted for launch in August 1984, but was canceled in the aftermath of the shuttle program’s first on-pad launch abort. The crew—Commander Karol “Bo” Bobko, Pilot Don Williams, Mission Specialists Rhea Seddon, Dave Griggs, and Jeff Hoffman, and Payload Specialists Jake Garn and France’s Patrick Baudry—were reassigned to Mission 51E, scheduled for early March 1985, which was itself canceled only days before launch, due to payload problems. At length, they found themselves earmarked for Mission 51D in mid-April. At face value, their payload looked relatively “vanilla,” but the dramatic Mission 51D would prove far from ordinary.

In fact, Mission 51D should have been a totally different flight with a totally different crew. Scheduled for launch later in March, it would have deployed the U.S. Navy’s Syncom 4-3 military communications satellite and retrieved NASA’s Long Duration Exposure Facility (LDEF) after almost a year in orbit. With the cancelation of 51E, the LDEF commitment was dropped from 51D, a second communications satellite—Canada’s Anik-C1—was added and there existed great media speculation that Bobko’s crew might receive assignment to the “new” 51D flight. They had trained for both Syncom and Anik deployment procedures, but the perspective of the crew was that they simply wanted to fly. “It was a stressful time,” Rhea Seddon remembered. “For most of us, it was our first flight and we didn’t care what they did to us, as long as they launched us!” The identities of the two Payload Specialists were also subject to change. By early April, Baudry had been bumped to a later mission and replaced by McDonnell Douglas engineer Charlie Walker—a member of the “original” 51D crew—whose company’s electrophoresis machine had already been installed onto the middeck of Shuttle Discovery.

On 12 April 1985, four years to the day since the first shuttle launch, the seven astronauts trooped out to Pad 39A, under very murky skies and a light drizzle, to board Discovery. Launch was scheduled for 8:04 a.m. EDT, on the opening of a 14-minute “window,” although a second opportunity ran from 8:45 until 9:00 a.m. “The weather was a little shaky,” Don Williams remembered, “because there was an overcast at about 12,000 feet (3,600 meters) or so. We didn’t think we were going to go and we were kind of just chatting around … because we figured we were going to do a scrub turnaround for 24 hours and come out the next day.” In fact, Dave Griggs, the flight engineer, had unstrapped and was sitting on the backrest of his seat, talking to Hoffman, Walker, and Garn on the middeck.

Flying Mission 51D, the crew finally launched on 12 April 1985, carrying the first serving politician into orbit...and embarked on a mission which proved unexpectedly dramatic. Photo Credit: NASA, via Joachim Becker/SpaceFacts.de

Flying Mission 51D, the crew finally launched on 12 April 1985, carrying the first serving politician into orbit … and embarked on a mission which proved unexpectedly dramatic. Photo Credit: NASA, via Joachim Becker/SpaceFacts.de

A freighter, the Ocean Mama, strayed into the drop zone for the boosters and had to be shooed away by the U.S. Coast Guard, causing a delay of almost an hour. As the second window opened with the clock in a planned hold at T-9 minutes, the crew were convinced that the attempt would be scrubbed. All at once, at 8:50 a.m. EDT, the call from the NASA Test Director in the Launch Control Center (LCC) crackled over the radio: an extension to the window had been granted and the clock was being manually restarted. Quickly, Hoffman strapped Griggs back into his seat and clambered downstairs to his own seat, next to the side hatch. “It was probably T-2 [minutes] before I really knew that I was finally going to go,” Hoffman recalled, “and then I was all psychologically set to go. That’s a very exciting time. Lots of things are happening. The shuttle is really alive and it’s moving!”

Jake Garn turned to Charlie Walker to ask what to expect.

“It’s gonna be great, Jake,” came the reply. “Just stay calm and enjoy it.”

Upstairs, from the pilot’s seat, Williams could see thick grey clouds; intellectually, he knew that they would not normally launch in such conditions, for fear of moisture damage to the orbiter’s thermal protection tiles. The launch itself, which came at 8:59 a.m. EDT, was “sort of like a two-minute-long catapult launch.” As they burst through the top of the cloud deck, he asked Bobko, half-jokingly, if he should give Mission Control a “tops report.” The commander responded with a curt “Shut up and watch your instruments!”

From Hoffman’s perch, the vibrations were one of the strongest sensations—reaching such intensity at one stage that he was convinced that Discovery’s wings were about to fall off, but the steady change from blue sky to black and the magical onset of weightlessness were profound. Numerous flights in the KC-135 parabolic aircraft had attuned his senses to the unusual environment, but now he was in a permanent state of free-fall. “That’s when it really hit me,” he said. “I floated over and I looked out the window and there was the Earth going by. You could see Africa off in the distance. Then I looked in the mirror and there was me in space. I just got this big ear-to-ear grin and I just couldn’t stop smiling for several hours! It was just such an elation.”

Mission 51D launched into space on 12 April 1985, the 24th anniversary of Yuri Gagarin's pioneering flight. Photo Credit: NASA

Mission 51D launched into space on 12 April 1985, the 24th anniversary of Yuri Gagarin’s pioneering flight. Photo Credit: NASA

For now, on 51D, five rookies were able to acclimatize themselves to their surroundings, but it soon became evident that Walker and Garn had been affected by space sickness. “I could tell that Jake’s feeling it about as rough as I am,” Walker recalled in a NASA Oral History, “and … this is my second experience and I had anticipated that, yes, I’ll probably have the same kind of symptoms and that was the case. Jake didn’t know what to expect.” Both Payload Specialists kept their movements to a minimum, avoiding so-called “zinging of the gyros” by moving their heads around too much in the first few minutes of orbital flight, but Garn’s reaction to the space environment was one of the most profound ever seen. One flight surgeon later joked that the “Garn Unit” had been created as a measure of nausea in astronauts. Clearly, Garn experienced severe space sickness and some rumors suggested that he was even incapacitated for a few days. “He has made a mark in the astronaut corps,” remembered oceanographer Bob Stevenson, “because he represents the maximum level of space sickness that anyone can ever attain … and so the mark of being totally sick and totally incompetent is ‘One Garn’. Most guys will get maybe a tenth [of a] Garn.”

Meanwhile, the first payload, Canada’s Anik-C1, was deployed at 6:38 p.m. EDT, almost 10 hours into the mission, and the camera on the shuttle’s Remote Manipulator System (RMS) mechanical arm captured the successful firing of its Payload Assist Module (PAM)-D motor shortly thereafter. Bobko and Williams performed a separation burn, which also served to slightly raise Discovery’s altitude in readiness for the release of the Navy’s Syncom 4-3 early the following morning. This did not go well. At 9:58 a.m. on the 13th, the giant satellite rolled out of the payload bay, but as it drifted away its omni-directional antenna failed to unfurl. Its anticipated “spin-up” maneuver to 33 rpm also failed to occur, and, 45 minutes after deployment, its solid-fuel perigee kick motor did not fire.

“We sort of looked,” Hoffman recalled. “Once we launch it—once it’s left the shuttle—our responsibility is finished. We moved away, just in case the engines fired, but of course they didn’t. Then, already on the ground, they were starting to think about contingencies. They told us to do another burn, because otherwise we would have kept moving further and further away from it.”

The Syncom 4-3 satellite drifts away from Discovery. The failure of its omni-directional antenna to deploy and of its solid-fueled perigee kick motor to ignite led to an impromptu rendezvous and repair attempt. Photo Credit: NASA

The Syncom 4-3 satellite drifts away from Discovery. The failure of its omni-directional antenna to deploy and of its solid-fueled perigee kick motor to ignite led to an impromptu rendezvous and repair attempt. Photo Credit: NASA

By the third day of the mission, consensus had been reached that an attempt would be made to revive Syncom 4-3. The flight was extended by 48 hours from five to seven days to accommodate this effort. The crew had followed their procedures correctly and the only possible cause of the failure was something called a “deploy switch,” which should have popped open as the satellite rolled out of the payload bay and triggered a timed sequence of events, leading up to the ignition of the perigee kick motor. On the ground, the switch was held in position by a piece of foam rubber and it appeared likely that this had not been removed before flight.

Fortunately, it was an external switch and Mission Control felt that a contingency EVA by Hoffman and Griggs might be able to trip it. The astronauts barely remembered the switch. They had visited the factory, many months earlier, when their original Mission 41F included a Syncom as part of its payload, but did not recall ever having been shown the deploy switch. However, that was only part of the problem now facing Bobko’s crew. They were being asked to re-rendezvous with Syncom in order to enable Hoffman and Griggs to conduct their spacewalk and Seddon to use the RMS to trip the switch.

Almost a year had passed since the cancellation of Mission 41F, which originally included a rendezvous with a free-flying Spartan satellite. Their mission had long since changed and their rendezvous skills were now rusty. “We had not done a rendezvous simulation … in seven months or so,” Bobko told the NASA oral historian, “and we didn’t have the books to do the rendezvous, so they sent us up this long teleprinted message.” The message was then cut up and pasted into their unneeded post-insertion checklist to create a makeshift rendezvous book. Moreover, although Hoffman and Griggs had done contingency EVA work in support of Spartan—in the region of 50 hours or more—none of it was recent and none of it was in direct support of Mission 51D’s payloads. Since an EVA was not planned, no mobile foot restraints were aboard the shuttle, and efforts by astronauts in the Weightless Environment Training Facility (WETF) at the Johnson Space Center (JSC) in Houston, Texas, to identify workarounds proved unsatisfactory.

It would be a tricky—and highly risky—task.

 

The second part of this article will appear tomorrow.

 

 

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3 comments to ‘It’s Gonna Be Great’: 30 Years Since Shuttle Mission 51D (Part 1)

  • Gary Church

    “135 missions flown by NASA’s five-strong fleet of shuttle orbiters between April 1981 and July 2011”

    Thanks for the factoid Ben. It is sad that many Americans feel the Shuttle was a failure. I have referred to it this way in many comments. Whenever I remember to, I try to qualify this statement though, with the caveat that if we take advantage of all the lessons of the shuttle it will be worth every penny.

    One of the first lessons is of course, don’t send people up to launch a satellite. The most practical system would have had the engines in a separate reentry package with a heat shield that enclosed itself in a seawater proof fairing or tarp and parachuted into the ocean. This would have allowed far more flexibility on what to attach to the External tank.

    The giant cargo bay of the shuttle is a riddle that is best solved by the bizarre rumor it was meant to hold a kidnapped Soviet spy satellite. It is crazy enough to be true. Why else the giant cargo bay? There was never any real expectation of needing to bring something back down so it was, as a practical design feature, not logical.

  • Rex Ridenoure

    The statement about the deployment switch in the article isn’t quite accurate:

    “The crew had followed their procedures correctly and the only possible cause of the failure was something called a ‘deploy switch,’ which should have popped open as the satellite rolled out of the payload bay and triggered a timed sequence of events, leading up to the ignition of the perigee kick motor. On the ground, the switch was held in position by a piece of foam rubber and it appeared likely that this had not been removed before flight.”

    I was a systems engineer at Hughes on the Syncom 4 spacecraft series (called LEASAT at Hughes), a systems test conductor on LEASAT F3 and in Hughes mission control when all of this played out. Within seconds after Shuttle Mission Specialist Rhea Seddon called out that the F3 omni antenna had not deployed as sequenced 30 sec. after spacecraft ejection from the cargo bay, LEASAT Mission Manager Andy Ott realized that the post-ejection sequencer had very likely not operated as planned. Within about an hour he formed a tiger team of ~12 LEASAT systems and test engineers to run through a fault-tree analysis to explain the anomaly.

    Within about 12 hours, the team concluded that there were only two ways that the post-ejection sequencer could not operate: either the single deployment switch mentioned in the article did not function as designed, or a pair of redundant limit switches installed at the separation plane between the donut-shaped structural frame carrying the solid rocket Perigee Kick Motor (PKM) and spacecraft frame did not — both of them. These limit switches were designed to permanently disable the post-ejection sequencer (a small avionics unit with triple-redundant timer circuits) once the spent PKM was ejected from the spacecraft after its successful operation.

    Based on its inherent simple design, extensive testing and excellent close-out photos taken before launch, the team had concluded that it was very, very unlikely that the single deployment switch had somehow failed, but addressing this possibility was the only one of the two possible failure scenarios the Shuttle and its crew could address, by basically rendezvousing with the lifeless, drifting F3 spacecraft and somehow yanking on the switch in case it inexplicably did not extend to its full OUT position and thus not enabling closure of a power circuit which would start up the post ejection sequencer. (The extremely strong spring forcing this switch out virtually assured that the spring would fully deploy — no matter what.) No one at Hughes believed that foam had been left in the switch mechanism.

    At this time early in the Shuttle era, NASA was looking for every opportunity to demonstrate the capabilities and promise of the Shuttle fleet and well-trained astronaut crews, so adding a couple of days to the planned mission schedule to accommodate an attempted ‘rescue’ of an errant satellite fit the bill quite nicely. As summarized in part 2 of this article, everyone rallied and pulled it off.

    But all along (at least at Hughes) it was considered a long shot that the deploy switch had somehow hung up and not extended, which is what all observations indicated once the orbiter had chased F3 down and gotten a closer look.

    In fact, at this time the LEASAT F4 spacecraft was nearing final assembly in the Hughes high bay (El Segundo, CA), and before the STS 51D mission was over careful measurements of the PKM separation limit switches — a nearly identical pair of switches installed in the same way — indicated that they were both installed incorrectly, and a bit too close to their designed trip settings. Further analysis convinced the LEASAT team that both of these switches very likely opened up prematurely during the rough ride from liftoff to orbit and stayed open, thus disabling the power to the post-ejection sequencer and never giving it a chance to operate.

    Operating on this confident conclusion (especially since the STS 51D ‘rescue’ revealed no anomaly with the deployment switch), a clever F3 capture/”hot-wire”/re-deploy salvage mission concept was conceived by the LEASAT/NASA team, and during another Shuttle mission ~3 months after STS 51D the crew re-rendezvoused with F3, captured it (manually!), attached the hot-wire kit, activated the kit and redeployed the spacecraft. Everything worked, and F3 eventually made it to GEO and for years provided UHF communications services to the U.S. Navy as planned, albeit a little late.

    One of the big lessons learned from the F3 anomaly: if your design includes redundant switches to open or close a power circuit, make sure that the switch designs are implemented differently so that a single installation error does not negate the redundancy!

  • […] Spacelab-3 was actually the second voyage of the joint U.S./European research facility, following the inaugural mission of the pressurized module aboard STS-9 in the fall of 1983. Spacelab-2 was intended to be a Verification Flight Test (VFT) of the unpressurized pallet and igloo combination, but had encountered technical difficulties with the Instrument Pointing System (IPS) and ended up being slipped until after Spacelab-3. Consequently, the module and a Multi-Purpose Experiment Support Structure (MPESS) were loaded into Challenger’s payload bay on 10 April, and the shuttle stack was transferred to Pad 39A at the Kennedy Space Center (KSC) just five days later. (In fact, only three days had elapsed since the launch of Mission 51D.) […]