Amid cloudy conditions, only days after the departure of Hurricane Debby and having sustained a pre-launch strike on the Lightning Protection System at Pad 39B, NASA’s 99th space shuttle rocketed into orbit 15 years ago, this coming week. On 8 September 2000, Atlantis and her seven-man STS-106 crew—Commander Terry Wilcutt, Pilot Scott Altman, and Mission Specialists Ed Lu, Rick Mastracchio, Dan Burbank, and Russian cosmonauts Yuri Malenchenko and Boris Morukov—began a mission, which barely eight months earlier, was only just beginning to appear on NASA’s radar for the year. As described in yesterday’s AmericaSpace history article, STS-106 was inserted into the shuttle manifest when it was recognized that the increasing complexity of a previous mission, STS-101, required it to be split into two discrete halves. Slated to run for at least 11 days, STS-106 was tasked with delivering upwards of 6,600 pounds (3,000 kg) of supplies to the International Space Station (ISS), thus preparing its newly-arrived Zvezda service module for the first long-duration crew, as well as executing a six-hour EVA by Lu and Malenchenko to hook up cables and utilities between the new module and the rest of the outpost.
As recounted yesterday, the decision to fly STS-106 hinged upon repeated delays in the launch of the Russian-built-and-financed Zvezda, which provided early crew quarters, life-support systems and command and control operations for the fledgling ISS. Its criticality could not be underestimated, for until Zvezda was in place, the first long-duration crew could not fly. Nor, indeed, could an intricately planned sequence of shuttle flights to deliver the first elements of the Integrated Truss Structure (ITS), four sets of expansive solar arrays and batteries, and a series of pressurized modules, including the U.S. Destiny laboratory and the Quest airlock take place. Originally targeted to fly in 1998, Zvezda’s construction and testing was repeatedly delayed, as Russia endured a vicious post-Soviet economic crisis, before eventually settling on a target launch date of November 1999. This date quickly proved untenable, when two Proton-K boosters exploded during ascent in July and October of that year. Since Zvezda would also fly a Proton-K, its launch again met with delay, pending an investigation. Finally, on 12 July 2000, Zvezda roared into orbit and, two weeks later, docked perfectly at the aft end of the station’s Zarya module. “The floodgates have been opened,” said veteran flight director Wayne Hale, “and we’re in high gear.”
Reaching orbit just 8.5 minutes after her 8:45:47 a.m. EDT liftoff, Atlantis and her crew wasted little time preparing for their lengthy mission. At the time of orbital insertion, they trailed the ISS by about 6,600 miles (10,600 km), aiming for a rendezvous and docking in the small hours of 10 September. During the transit, Wilcutt and Altman worked to prepare navigational tools for the task ahead, whilst Mastracchio powered-up the Canadian-built Remote Manipulator System (RMS) mechanical arm and conducted a photographic survey of the payload bay and Lu and Malenchenko—together with Burbank, who would serve as the Intravehicular (IV) crewman, choreographing their EVA from inside Atlantis—worked to prepare the two U.S.-built Extravehicular Mobility Unit (EMU) space suits. It would be only the second time, after STS-86, that Russians and Americans would embark together on an EVA in U.S. suits and, during training in the “hydrolab” at the Star City cosmonauts’ training center, near Moscow, it had marked the first time that the EMU had been used for exercises in a Russian underwater facility. “We’re the first shuttle crew to ever train in the hydrolab and that required us to bring a whole series of U.S. training suits and all of our hardware out to Russia and build adapters, such that our suits could be powered off of their oxygen supply systems,” explained Lu. “That required an awful lot of work by a lot of our engineers in order to make all this happen.”
In spite of the failure of one of Atlantis’ twin star trackers, Wilcutt smoothly guided the shuttle to a position about 9.2 miles (14.8 km) “behind” the ISS, late on 9 September, then executed the Terminal Initiation (TI) “burn” to arrive within a half-mile (0.8 km) of the station about 90 minutes later. In doing so, Wilcutt flew along the so-called “R-Bar”—or “Earth Radius Vector”—in which he approached the station from “below,” rather than “ahead,” in order to exploit Earth’s natural gravitational gradient to brake Atlantis’ approach and minimize the risk of plume impingement on the ISS flight surfaces. He then assumed manual control from the aft flight deck, maneuvering his ship to a point about 600 feet (180 meters) “below” the ISS, prior to executing a half-circle to approach his docking location at the Pressurized Mating Adapter (PMA)-2 “end” of the U.S.-built Unity node. “The way the space station is configured is we’re going to be docking with … the PMA, attached to the Node, which will be pointing “up” in relation to the Earth,” Mastracchio explained. “All the antennas that are used to communicate with the Russian ground sites are located on the service module and the [Zarya control module] on the bottom portion, so we want those clear of any structure, pointing towards the Earth, for a clear path of communication with the Russian ground sites. That forces us to fly over the top of the space station and dock with the node, which is pointing up.”
During this period, the crew was crowded into the shuttle’s tiny flight deck, with Wilcutt at the aft station, Altman in the Commander’s seat, computing the phasing burns, Mastracchio at the overhead windows with a hand-held laser rangefinder, Lu focusing on their relative position and rate of closure and Burbank handling the cameras and responsible for activating the Orbiter Docking System (ODS) in the shuttle’s payload bay. Elsewhere, Malenchenko and Morukov assisted with photographic and TV activities.
Finally, at 1:51 a.m. EDT on 10 September, a little more than 41 hours since departing Pad 39B, Wilcutt achieved a perfect docking at the PMA-2 interface of the Unity node. The only change to the original flight plan was a brief, 90-degree roll maneuver to sight the ISS with the sole remaining star tracker. By this stage in its evolution, the station measured an impressive 143 feet (43.6 meters) in length and weighed around 134,000 pounds (60,800 kg). Unlike many subsequent shuttle missions, the STS-106 crew would not open the hatches and board the ISS until later in the flight. In the absence of the Quest airlock, all shuttle-based EVAs were performed via the orbiter’s external airlock—whose trio of hatches extended inward into the middeck, outward into the payload and “upwards” into PMA-2—and it was intended that Lu and Malenchenko would begin their spacewalk late on the 10th. After the EVA had concluded, the crew would board the station to begin almost a full week of payload delivery and logistics transfer from the Spacehab Double Module in the payload bay and from the Progress M1-3 cargo ship, docked at the aft end of Zvezda since early August.
Shortly after docking, Atlantis’ cabin atmospheric pressure was lowered in readiness for the EVA, in order to reduce the amount of time that Lu and Malenchenko would need to “pre-breathe” pure oxygen before entering the airlock. Although Malenchenko had previously performed two EVAs during his stint as Commander of the Mir space station in July-November 1994—and at that point had totaled more than 11 hours working in the near-total vacuum of low-Earth orbit—it would be Lu’s first spacewalk. “You have to remind yourself every once in a while, hey, look at where you are for just a second,” he recounted in a pre-flight interview. “You know, take a look at the Earth for a second … sneak a peek at where you are and think about that every once in a while, so you don’t come back inside and say, wow, did that all really happen or not?”
The main task of the EVA, which marked the sixth spacewalk performed outside the ISS, since the initial excursions of STS-88 astronauts Jerry Ross and Jim Newman in December 1998, was to hook up a series of nine electrical, communications, and telemetry cables between Zvezda and Zarya, as well as installing a stowed magnetometer boom onto the hull of the service module to minimize its propellant consumption. The location of the magnetometer installation site was near the far end of Zvezda. Mastracchio would lift the pair about 50 feet (15 meters) above the payload bay, achieving the maximum reach of the RMS, after which Lu and Malenchenko would be required to clamber, hand over hand, along hand rails, to reach their worksite, at a position 110 feet (33.5 meters) from Atlantis, making this the furthest that tethered spacewalkers had ever ventured outside the shuttle. To place this distance into context, Lu and Malenchenko would be working at a location more than twice as high as the Hubble Space Telescope (HST).
The cables included four power connections, totaling 27 feet (8.2 meters) in length, which would be needed ahead of the STS-97 mission in November 2000 to support the first set of U.S.-built solar arrays, batteries, and radiators, enabling electrical power to flow to the Russian arrays on Zarya and Zvezda. Two additional cables would facilitate an internal closed-circuit video feed, another pair would link data from Zvezda to Zarya and enable solar array commanding and a final one would provide a fiber-optic link to allow data flow from Russian EVA suits after the installation of the Quest airlock in mid-2001.
When Lu and Malenchenko departed Atlantis’ airlock at 12:47 a.m. EDT on 11 September 2000, their excursion marked the 50th spacewalk in shuttle program history, more than 17 years since the initial EVA by astronauts Story Musgrave and Don Peterson outside Challenger on STS-6 in April 1983. The duo immediately moved to the toolbox to collect wire cable spools and equipment and attached them to Body Restraint Tethers (BRTs) on their suits. Unlike previous shuttle-based EVAs, where the astronauts were secured to the same tether, the Russian segment of the ISS did not have the capability to run a retractable tether from the slidewire. “What you do in the shuttle is you attach yourself by this tether which you never disconnect, and that way you can move around the shuttle payload bay or move around the station without just using your two hands to move around without worrying about tethering off to places,” Lu explained before launch. “However, we’re going to be moving around the station and around various targets and sensors and things like that, so we will not be able to drag behind us a long tether, which is … going back many feet.” Added Malenchenko: “The translation path is quite long and we will have to go around a number of antennas and targets, so we need to be very careful not to touch them or misplace them.”
As a consequence, Lu and Malenchenko employed a pair of tethers and would constantly make and break connections, “sort of like the way a rock-climber might move,” as they headed further along the hull of Zarya and Zvezda. Known as the “Russian Tether Protocol,” it had been used for many years by cosmonauts spacewalking outside Mir, but it was a slow process, requiring them to “load-up” all of their equipment onto the backs of their suits, “and basically be pack mules all the way out there.”
Mastracchio elevated them on the RMS to its maximum extent along the exterior of the space station, reaching the forward end of the Zarya module. Equipped with Simplified Aid for EVA Rescue (SAFER) backpacks for self-rescue, if needed, Lu and Malenchenko then set about maneuvering themselves a further 60 feet (18 meters) up the “stack” to reach the magnetometer work site. Working about 40 minutes ahead of schedule, the spacewalkers mounted the magnetometer head onto its 10-foot (3-meter) boom, bolted it into place and secured wire with cable ties, before heading back along the Zvezda-Zarya stack towards the shuttle’s payload bay. They also successfully freed a jammed docking target on the service module, before pressing into the cable installation task, which was complete by 6 a.m. EDT, a little more than five hours into the EVA. After stowing their tools and equipment, Lu and Malenchenko returned to the airlock and the spacewalk ended at 7:01 a.m., after six hours and 14 minutes.
With the EVA behind them, the next task was to begin the laborious process of opening a dozen hatches to access the Unity node, with its PMA-1 and PMA-2 interfaces at each end, the Zarya and Zvezda modules and, at the far end of the space station, the newly-arrived Progress M1-3 cargo ship. The first hatch was opened late on 11 September and the final hatch was open about four hours later. Entering Zvezda for the first time, led by Wilcutt and Malenchenko, the crew wore goggles and breathing filters as a guard again possible atmospheric contamination, although it soon became clear that the air quality was excellent. By this time, they had been advised by Mission Control that their cryogenic consumables margin was sufficient to permit a 12th flight day, and an additional docked day at the ISS, and the STS-106 crew plunged into what would be almost a full week of cargo transfers and equipment installation on the new space station.
Over the course of that week, power converters were installed, a new treadmill was set up, batteries were removed and replaced aboard Zarya and Zvezda—requiring Burbank and Morukov to use a hammer and chisel at one point—and the station’s orbit was reboosted on four discrete occasions. Although cargo transfers had characterised STS-101 in May 2000, and had also been performed during nine shuttle-Mir docking missions between June 1995 and June 1998, the achievement of STS-106 was decidedly more complex, for the crew would be unpacking the Spacehab Double Module in the payload bay and overseeing the unpacking of Progress M1-3 at the opposite end of the station. Mastracchio led the Spacehab effort, whilst Morukov led the Progress effort, with Burbank providing oversight. Another key difference, of course, was that during shuttle-Mir, a station crew was on hand to provide assistance. “All we had to do was get the stuff off the shuttle,” said Lu, who flew one of the shuttle-Mir missions, “and you would hand it to a cosmonaut. And so, pretty much, you were only responsible for half of it. On this flight, we are the station crew, also.”
At length, late on 17 September, the final hatches were closed and Atlantis undocked from the station at 11:46 p.m. EDT. Altman then performed a flyaround inspection for photographic survey purposes and Wilcutt offered a few words of advice for the first long-duration crew, whose own launch was barely six weeks away: “Enjoy it like a new home!” Two days later, with near-perfect conditions anticipated on the Shuttle Landing Facility (SLF) at the Kennedy Space Center (KSC) in Florida, preparations got underway to bring Atlantis and the STS-106 crew home. The irreversible burn of the Orbital Maneuvering System (OMS) engines occurred at 2:50 a.m. EDT on the 20th, committing the shuttle to an hour-long glide from the mid-Indian Ocean to the eastern seaboard of the United States. Touchdown on a darkened Runway 15 took place at 3:56 a.m. EDT, wrapping up a voyage of 4.9 million miles (7.9 million km) and 185 circuits of Earth in a little less than 12 full days.
STS-106 had been a remarkable mission; remarkable in many senses, not least in that it had served to prepare Zvezda—the station’s critical living quarters—for the arrival of Expedition 1 crew members Bill Shepherd, Yuri Gidzenko, and Sergei Krikalev in early-November 2000. “The whole station is about people living in space and this is the crew quarters,” said Terry Wilcutt. “And when we say crew quarters, it’s got their sleeping compartments, it has the life support, it’s got the kitchen, basically the galley, the breathing equipment to allow people to live there and recycle oxygen, water, it’s got the attitude control for the entire station…it’s literally the life-support component and the control component for the rest of the station. You have to have it. It’s the place to life and provides the systems to allow you to live in the space station.”
And thanks to the work of STS-106 and her crew, Zvezda continues with this fundamentally important task to this very day, exactly 15 years later.
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 the 20th anniversary of STS-69, a dramatic mission of spacewalking, rendezvous, satellite deployments and retrievals, which put virtually all of the Space Shuttle’s capabilities to the ultimate test.