A Legacy of Women in Space: Twenty Years Since STS-57 (Part 2)

With the RMS robotic arm deftly operated by Nancy Sherlock, astronauts David Low and Jeff Wisoff are maneuvered around Endeavour's payload bay. The Spacehab module is clearly visible in the foreground. Photo Credit: NASA

With the RMS robotic arm deftly operated by Nancy Sherlock, astronauts David Low and Jeff Wisoff are maneuvered around Endeavour’s payload bay. The Spacehab module is clearly visible in the foreground. Photo Credit: NASA

Fifty years ago this month, the first woman ventured into space. Thirty years ago, also this month, the first U.S. woman ventured into space. And twenty years ago this very week, two women from quite different backgrounds—U.S. Army aviator Nancy Sherlock (now Currie) and civilian engineer Janice Voss—flew together into space for the first time. STS-57 was not the first mission in history to include two female members. Nor was it the first mission to feature a military woman among its crew. However, with the presence of both civilian and military women aboard Endeavour when she rocketed into orbit in June 1993, it offered a reminder of how far women astronauts had advanced in a mere handful of decades.

Rocketing into orbit posed something of a problem on the morning of 20 June, when bad weather at the Transoceanic Abort Landing sites put paid to hopes that Pilot Brian Duffy might celebrate his 40th birthday in style. As described in yesterday’s history article, STS-57 was an important mission, carrying the first commercial “Spacehab” research laboratory and destined to recover the European Retrievable Carrier (EURECA) after ten months in orbit. Next morning, the 21st, conditions had improved markedly, but as the six astronauts—Duffy, Sherlock, and Voss, together with fellow crewmates David Low and Jeff Wisoff and Commander Ron Grabe—boarded Endeavour a scratch was observed on the outer seal of the crew access hatch. After consultation with mission managers, it was decided to replace the seal, and this was accomplished with little impact on the countdown.

At T-5 minutes, the hold was extended by 22 seconds in order to shoo an unauthorised aircraft out of the launch danger zone and STS-57 rocketed off the pad at 9:07 a.m. EDT. The ascent was electrifying, particularly for the three “rookie” members of the crew, with Main Engine Cutoff and the onset of weightlessness both memorable. “The bear jumps off your chest,” remembered Jeff Wisoff in an interview for the Smithsonian, “and you see your seatbelts float upward, which is kinda cool.”

Endeavour rockets into space on 21 June 1993, beginning the first mission to include military and civilian female crew members. Photo Credit: NASA

Endeavour rockets into space on 21 June 1993, beginning the first mission to include military and civilian female crew members. Photo Credit: NASA

Despite initial difficulties, the shuttle’s Remote Manipulator System (RMS) mechanical arm was initialized and checked out, in readiness for the retrieval of EURECA on the third day of the flight. A number of thruster firings were performed by Grabe and Duffy over the next 48 hours to effect closure with EURECA, whose orbit had already been lowered under ground command in recent weeks from its operational altitude of 320 miles to more closely approximate Endeavour’s altitude of some 190 miles. With Grabe at the shuttle’s controls for the final phases of the rendezvous, the satellite was successfully grappled by the RMS, under the deft control of David Low, at 9:53 a.m. on 24 June. Endeavour’s Ku-band radar satisfactorily tracked the satellite from a distance of 30 miles to less than 100 feet, with no loss of data. Although EURECA’s solar arrays successfully folded up, its two antennas—which should have retracted and latched prior to grappling—failed to close. As a consequence, it was decided to use a portion of Low and Wisoff’s planned spacewalk on the 25th to tend to the problem.

An EVA was not originally planned for STS-57, but in the aftermath of the Intelsat-603 repair mission NASA decided in late 1992 to add spacewalks to as many shuttle flights as possible in order to build up an experience base within the astronaut office. In mid-February 1993, an EVA was added to STS-57, during which Low and Wisoff would spend four hours outside “to refine training methods for spacewalks, expand the EVA experience levels of astronauts, flight controllers, and instructors, and aid in better understanding the differences between true microgravity and the ground simulations used in training.” Since Endeavour carried the RMS arm for the EURECA retrieval, it was decided to make use of it to rehearse procedures ahead of the Hubble Space Telescope servicing mission in December 1993. However, the criticality of Low and Wisoff’s EVA was of a low level and it was stressed that only if STS-57’s nominal mission duration was extended from seven to eight days would it be cleared to take place.

The decision was to be made shortly after launch and was based upon calculations of the propellant and energy expenditure and how well they matched predictions. Fortunately, these proved to be in line with expectations and on 23 June the Mission Management Team agreed to extend STS-57 to eight days. Plans for the EVA involved Low and Wisoff taking turns in a foot restraint on the end of the RMS—manipulated by Nancy Sherlock—and handling each other’s mass to imitate the movement of large pieces of equipment. Moving large masses on the end of the mechanical arm was expected to be a critical requirement for both Hubble and Space Station Freedom missions. The spacewalkers also trained to investigate techniques for managing their safety tethers. The EVA, which ran to five hours and 50 minutes in total, ran exceptionally smoothly, with Sherlock positioning Low on the RMS to enable him to secure EURECA’s antennas against their latching mechanisms. Payload controllers then remotely drove the latches to secure each antenna.

Since the EVA required the astronauts to depart Endeavour via the middeck-to-Spacehab tunnel, it was necessary for the pressurized module to be temporarily closed off. Subsequent investigation revealed no pressure loss from Spacehab during this time. It may, however, have induced an event which scared the daylights out of the four crew members inside the cabin. During the EVA, the shuttle was positioned with her belly toward the Sun, in order to simulate the deep cold of space which would be experienced at phases of Hubble servicing and Space Station Freedom construction.

David Low (right) and Jeff Wisoff at work during their EVA. Photo Credit: NASA

David Low (right) and Jeff Wisoff at work during their EVA. Photo Credit: NASA

“All of a sudden, it was as if somebody took the orbiter and hit it with a bulldozer,” recalled Brian Duffy in his NASA oral history. “The whole vehicle shook. It got quiet on the flight deck and we thought maybe we were hit by something. We looked outside and didn’t see any damage. Nothing came flying through the wings or through the payload bay.” They informed Mission Control, who also saw nothing amiss in their data. The most likely explanation, it seemed, was that residual forces that had built up on the ground in the struts holding the Spacehab-1 tunnel in place had released “and it rang the whole vehicle.” When the two spacewalkers returned to the cabin, they said that they had felt nothing. “They didn’t have a clue,” Duffy chuckled, “but if they’d looked inside at that time, they would have seen eight big eyes!”

Low and Wisoff’s EVA demonstrated the importance and usefulness of having astronauts on hand to tend to unforeseen contingencies. It also provided EVA experience for another pair of astronauts, including the first spacewalk for a member of the 1990 astronaut class. Years later, Wisoff was asked about it by a NASA interviewer. “It’s an incredible opportunity,” he said, “an incredible experience. You’re kind of in your own little spaceship in the space suit and you can’t beat that view of the Earth while you’re working. It’s an incredible sight!” Despite the successful closure of EURECA’s twin antennas, an attempt to activate the RMS arm’s Special Purpose End Effector (SPEE) connector power relay, which was to provide electrical sustenance to the satellite, failed. It subsequently became clear from on-orbit video footage and post-flight inspection that the SPEE had been incorrectly rotated by 180 degrees.

Spacehab-1, in particular, proved to be an enormous success. The module’s interior environment had a tendency to be quite cool at times, prompting a pair of in-flight maintenance procedures by the astronauts to successfully adjust the cold-water bypass valve and increase the temperature slightly. The cause was later attributed to lower electrical power requirements for Spacehab than had been predicted in pre-flight tests. In other words, it was not generating as much waste heat as predicted, but the cooling system was still working at full capacity. Overall, the module’s experiments exceeded 90 percent of plans. The mission was challenging for all six crew members, including Grabe, who had never done rendezvous or EVA on any of his previous three missions. “We had Ron kinda carrying the ball,” Brian Duffy recalled. “Particularly in the training, he was just really good about knowing what was important for us, what we needed to know, what we should focus on.”

With a one-day extension to the mission, STS-57 was scheduled to land on 29 June, but Endeavour’s return actually came 48 hours later than planned. Unsatisfactory weather in the vicinity of the Shuttle Landing Facility at KSC forced a one-orbit wave-off, and when there was no improvement a 24-hour postponement was ordered. The next day, the 30th, offered no respite and another 24-hour delay was imposed. Finally, early on 1 July, Grabe and Duffy performed the de-orbit burn at 7:41 a.m. EDT, committing the vehicle to its hypersonic dive through the atmosphere. Touchdown on Runway 33 came an hour later at 8:52 a.m., just 15 minutes short of ten full days since liftoff.

Endeavour touches down within sight of the gigantic Vehicle Assembly Building (VAB) on 1 July 1993. Photo Credit: NASA

Endeavour touches down within sight of the gigantic Vehicle Assembly Building (VAB) on 1 July 1993. Photo Credit: NASA

The re-entry, Duffy related, was nominal, but characterised by one unanticipated event. “This one was a flatter, lower trajectory” than his first flight, he said. “We were coming across northern Mexico and then across the Gulf, coming in almost due east, and it was … after sunrise, maybe mid-morning.” All at once, as they passed through Mach 21, a sudden wham echoed through the vehicle’s airframe. About 30 seconds later, another one followed. Nancy Sherlock, sitting in the flight engineer’s seat, looked up in surprise after the first event, but noticed that Grabe and Duffy—the veterans—seemed unperturbed and said nothing. When it happened again, Grabe turned to his pilot.

“Have you ever felt that before?”

“No,” replied Duffy, perplexed. It later became clear that Endeavour had been shaken by a “density shear”—an air-mass differential at extreme high altitude, which Endeavour had transitioned at hypersonic speed. “Those things extend up at a high altitude,” Duffy reflected later, “and when you’re going very fast and you change from one to the other, you get an instantaneous notification that you’re somewhere else. It’s like somebody really picks up and shakes the whole orbiter. The whole vehicle rings, because [it’s] not very sturdy. It looks sturdy, [but] it’s about as stiff as a Twinky and, truth be known, during ascent you can actually feel it flexing.”

With the exception of an ammonia cooling glitch on the runway, which required Grabe to work closely with ground crews to establish cooling and prevent an emergency power-down, Endeavour’s return from her fourth flight was a spectacular success. It also cemented life-long friendships for the STS-57 crew and reinforced memories of their flight. “Nancy and I were on the flight deck one night,” said Duffy, during the weather wave-off period, “where we were waiting to go to bed—basically hanging out—and she and I were upstairs, turned all the lights out on the flight deck and the two of us just sat there and floated in the window and watched the Earth going by in the dark. It was pretty neat.” The down side of having to spend two additional days in orbit was that they had to budget their camera film and by 1 July it was all gone. “We didn’t even have film to shoot” at the end, noted Duffy, “so we just got to look and just enjoy it. It was really cool.”

The safe return of the STS-57 crew, two decades ago, marked yet another milestone in the history of women in space, with military and civilian female astronauts aboard the same mission for the first time. Barely three decades had passed since Valentina Tereshkova became the first woman in space and a mere ten years since Sally Ride picked up the baton for the United States. In that span of time, a woman had walked in space, three women had flown aboard a single mission, and the first African-American woman astronaut had been launched. In the ten years after STS-57, the first female shuttle pilots would fly missions, and in the ten years after that the first female International Space Station commanders. Earlier this month, NASA selected its 21st group of astronaut candidates. Eight strong, and including four women, they mark the most evenly matched mix of the sexes in any astronaut (or cosmonaut) selection in history. Today, in June 2013, two women—China’s Wang Yaping aboard the Shenzhou-10/Tiangong-1 complex and NASA’s Karen Nyberg aboard the ISS—continue the legacy.

And what of the next ten years? And the ten after that? The first woman on the Moon, perhaps? The first female to set foot on an asteroid … or even Mars? The door to the future stands open.

 

 

This is part of a series of history articles, which will appear each weekend, barring any major news stories. Next week’s article will focus on Soyuz T-6, a mission in June 1982, during which France became the first Western European nation to launch its first man into space … aboard a Soviet spacecraft.

 

 

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