Fifteen years ago, next week, the second human to launch from Earth as many as seven times began what would be his final space mission. Costa Rica-born U.S. plasma physicist Dr. Franklin Chang-Diaz, it might be supposed, had seen and done everything during his two-decade astronaut career. He had deployed and retrieved satellites, had performed scientific research and rendezvous and had even launched a spacecraft to Jupiter, but in none of his six prior flights had he ever made a spacewalk. That would change on Space Shuttle mission STS-111.
When he was assigned to the STS-111 crew in July 2001, Chang-Diaz confidently looked forward to performing two sessions of Extravehicular Activity (EVA). But what he could not have anticipated was that he and French astronaut Philippe Perrin would go on to make three spacewalks—totaling more than 19.5 hours—during their 14 days in orbit in June 2002. The crew, or rather crews, for STS-111 were assigned at variously different times. It was expected that the shuttle would deliver the Expedition 5 crew of Commander Valeri Korzun and Flight Engineers Sergei Treschev and Peggy Whitson to the International Space Station (ISS) and return to Earth with the Expedition 4 crew of Commander Yuri Onufrienko and Flight Engineers Carl Walz and Dan Bursch. The Expedition 4 crew had been in formal training for their multi-month increment since November 1997, whilst Korzun’s crew had been officially announced in March 2001.
Meanwhile, the four-strong STS-111 “core” crew was also announced in two parts, with Perrin named as a Mission Specialist in February 2001. “It was unreal until I got the whole crew being assigned,” Perrin later recalled. “For me, it took the whole crew to be assigned a few months later to really understand that I would go and fly in space.” When the remainder of the crew—Commander Ken Cockrell, Pilot Paul Lockhart and Chang-Diaz—were named in July, the reality began to set in. With Cockrell making his fifth shuttle flight, and Chang-Diaz his seventh, “rookies” Perrin and Lockhart had a pair of excellent role-models from which to learn.
“It was quite different from training in the simulator,” said Perrin, “to talk to these people, who had so much experience.” Lockhart agreed. Whenever he had a question—what would something sound like, what would he feel at a particular stage in the flight or what should he be paying attention to at a specific point—he approached Chang-Diaz. “And he always had the answer” said Lockhart, a point echoed by Perrin. “Franklin is very detail-oriented. He’s going to tell me everything about the first second we hit MECO [Main Engine Cutoff] and here we are in space and what do I need to do with my helmet, with my gloves, and how am I going to react; what I should do, not do? It’s quite unique to fly with somebody with so much experience.”
Another interesting facet was the relationship between Cockrell and Chang-Diaz, for both men (separated by just four days, in terms of age) had arrived in Houston, Texas, for their astronaut interviews on the very same day in March 1980. “Franklin and I both got off the same airplane,” remembered Cockrell. “We arrived in Houston and we were standing around the terminal, waiting for the car from the hotel to come pick us up. And struck up a conversation, realized what we were both here do…and now we’re flying together for the first time.” The pair were interviewed in the same group—a group which also included future NASA Administrator Charlie Bolden—and, although both Chang-Diaz and Bolden went on to be selected a few months later, it would take four more applications before Cockrell was chosen as an astronaut in January 1990.
STS-111’s primary payload was the Canadian-built Mobile Base System (MBS), which would serve as a “shoulder” for the 57.7-foot-long (17.6-meter) Canadarm2 robotic arm. From the outset, it had been expected that Canadarm2 would operate across wide distances, running via the railroad-like Mobile Transporter (MT) along the station’s 356-foot-long (108.5-meter) Integrated Truss Structure (ITS) to install, replace and repair hardware. However, in order for Canadarm2 to interface with the rails of the MT—and therefore transition from being a “fixed” robotic arm, secured to the station’s U.S. Destiny lab, to a movable one—the MBS had to be installed.
“The Mobile Base System as an interface means that the station robotic arm can receive electrical power and data and also return…parameters of its condition…back to the computers on the station, so that we know the status of the arm,” explained STS-111 Pilot Paul Lockhart, before the flight. “No longer are we restricted to having the station robotic arm in one location.”
Also aboard Endeavour for STS-111 was the Italian-built Multi-Purpose Logistics Module (MPLM), dubbed “Leonardo”, which was making its third mission, after debuting on STS-102 in March 2001. Measuring 21 feet (6.4 meters) long, the cylindrical module would go on to make a total of eight flights, before being permanently added to the ISS as the Permanent Multipurpose Module (PMM) in March 2011. Aboard Leonardo for STS-111 was a total of 5,600 pounds (2,540 kg) of equipment and supplies, including eight Resupply Return Stowage Racks (RSRs), five Resupply Stowage Platforms (RSPs), a pair of International Standard Payload Racks (ISPRs) and two scientific racks—an EXpedite the PRocessing of Experiments to Space Station (EXPRESS) rack and the Microgravity Science Glovebox (MSG) rack—to be installed into the station’s U.S. Destiny lab.
Designated “Utilization Flight-2” (UF-2), STS-111 was so named because it was originally meant to be a scientific mission, delivering 5,600 pounds (2,540 kg) of equipment and supplies to the station. In particular, it would carry eight Resupply Return Stowage Racks (RSRs) and five Resupply Stowage Platforms (RSPs)—fully laden with cargo transfer bags—as well as pair of International Standard Payload Racks (ISPRs) for installation aboard Destiny. One of these racks was a multi-purpose EXpedite the PRocessing of Experiments to Space Station (EXPRESS) unit, whilst the other carried the Microgravity Science Glovebox (MSG) for hands-on scientific research.
“When it was originally manifested, it was meant to bring up some more science in the MPLM and use the shuttle to get experiments to station and therefore “utilize” us as a facilitator for keeping science going and operations going on the space station,” explained Cockrell. Two EVAs were planned from the outset, but in spring 2002 the failure of a wrist joint aboard Canadarm2 led to the addition of a third spacewalk by Mission Specialists Chang-Diaz and Perrin to effect a repair. “The fact that we now have three EVAs,” continued Cockrell, “makes us look a lot more like a construction flight.” Coming on the heels of Assembly Flight 8A, he jokingly added that STS-111 “could very well be called “8A-and-a-half”. But we’re called UF-2”.
The failure was centered on the roll joint of Canadarm2’s “wrist”, which triggered some degradation in the maneuverability of the 500-pound (225 kg) Latching End Effector (LEE). STS-111 would carry a new roll joint, but the repair task required a delay of several weeks to the launch to allow the crew to train for it. Originally scheduled to fly in early May 2002, the mission found itself moved to early June, and that resulted in an extension of Expedition 4’s time in orbit from 5.5 months to 6.5 months. “That was a little bit of a tradeoff that the Space Station Program had to make,” said Cockrell, “but in the end, they decided it was more important to get the arm working. It’s very key to all these assembly missions.”
The reaction of the rest of the crew was mixed, but overly positive. Chang-Diaz took it in his stride, whereas Perrin was working in the Neutral Buoyancy Laboratory (NBL), near the Johnson Space Center (JSC) in Houston, Texas, when he heard the news. “I realized I would fly a little bit later, which was…a little sad, because you’re already at that point of the training,” he recalled. “I feel ready, but at the same time I understood how critical that third EVA would be and we definitely need to repair the Canadian arm. I thought it was very interesting, very challenging and I personally like being challenged.”
“We happen to be at the right place, at the right time,” added Chang-Diaz. Although Canadarm2 carried some systems redundancy, the key issue was that further failures could result in a loss of functionality. Several future shuttle missions would deliver large pieces of hardware, all of which were dependent on the robotic arm. “We shall be very heavily loaded later in the assembly process,” he said, “so it’s very important to get this fixed quickly.”
After two weather-related delays, Endeavour launched into steadily darkening skies from Pad 39A at the Kennedy Space Center (KSC) at 5:23 p.m. EDT on 5 June 2002. During the dynamic phase of ascent—from the rattling opening two minutes on the Solid Rocket Boosters (SRBs) to the smooth-as-glass ride to orbit on Endeavour’s cluster of Space Shuttle Main Engines (SSMEs)—that their training took over. “I was able to stay equal and ahead of the vehicle on what was happening and to keep up and know what the next event was, due to the training,” recalled Lockhart. “It was outstanding and it allowed me to know what was happening at all times.”
In fact, the only unexpected moment came six minutes into the ascent. Since STS-87 in November 1997, ascending shuttles had executed a 20-second “heads-up” maneuver, rolling 180 degrees from a belly-up to a belly-down orientation, to allow the astronauts to communicate with Mission Control through the Tracking and Data Relay Satellite System (TDRSS), several minutes sooner than previously possible. The maneuver took place six minutes after liftoff, beyond the “sensible” atmosphere, and was unseen to observers on the ground. Since it was commanded in real time by the shuttle’s General Purpose Computers (GPCs), the pilots had no idea if Endeavour would roll “left” (towards Cockrell) or “right” (towards Lockhart).
They took a light-hearted bet on it. Lockhart lost.
Achieving orbit a little under nine minutes after launch, the STS-111 crew set to work reconfiguring their vehicle into an orbital spacecraft and readying for docking at the ISS on 7 June. As Cockrell and Lockhart oversaw a series of maneuvering “burns” to steadily close the distance and align their orbital parameters with the space station, Chang-Diaz and Perrin set up a centerline camera in Endeavour’s Orbiter Docking System (ODS) to provide imagery during the final approach. They also checked out the Extravehicular Mobility Units (EMUs) which they would utilize during their three spacewalks.
By mid-morning on the 7th, they had closed to within nine miles (14 km) of their quarry and the incumbent Expedition 4 crew of Onufrienko, Walz and Bursch, who had been aboard the ISS since December 2001. At that stage, Endeavour performed a Terminal Intercept (TI) burn to begin the final rendezvous, with Cockrell controlling the vehicle from the aft flight deck and Lockhart in the Commander’s seat, overseeing a series of mid-course correction maneuvers. These positioned the shuttle about a half-mile (0.8 km) “below” the space station, allowing Cockrell to assume manual control for the final approach.
A former chief of NASA’s astronaut corps, Cockrell guided Endeavour to a point about 600 feet (180 meters) from his quarry, whereupon he commenced a quarter-circuit to move in line with Pressurized Mating Adapter (PMA)-2 on the forward end of the U.S. Destiny lab. Cockrell knew Destiny well, having commanded STS-98, the shuttle flight which installed the lab in February 2001. As Endeavour closed on the ISS, her flight deck was a hive of activity, with Cockrell and Lockhart running the rendezvous, Perrin handling navigational displays, Chang-Diaz operating the Orbiter Docking System (ODS) and Whitson providing supplemental range and closing-rate parameters, via a hand-held laser ranging device.
Pausing at 300 feet (90 meters), and again at 30 feet (9 meters) for final checks, Cockrell brought Endeavour to a smooth docking—and her fifth trip to the ISS—at 12:25 p.m. EDT. A little over 43 hours had elapsed since STS-111 rose from Earth and a busy mission of construction, crew-exchange and science now lay ahead. Watching the shuttle’s arrival from the windows of the space station, Bursch later remarked that it was “a great feeling, knowing that’s your ride home”.
The second part of this article will appear tomorrow.