Today, in the middle of the second decade of the 21st century, we have grown used to the presence of the International Space Station (ISS) and around-the-clock research in space no longer seems uncommon. Yet 20 years ago, as NASA’s Space Shuttle fleet averaged seven missions per year, each one flying for no longer than a couple of weeks at a time, the ability to conduct “hands-on” research in the peculiar microgravity environment of low-Earth orbit was considerably less frequent. In reflection of this reality, and to prepare for future ISS research, a number of shuttle missions were outfitted with the Extended Duration Orbiter (EDO) capability, which allowed for longer flights, in excess of 16 days. On 20 October 1995, Shuttle Columbia rocketed into orbit for one such EDO mission. In her payload bay was the bus-sized Spacelab module, outfitted for the second United States Microgravity Laboratory (USML-2). For almost 16 days, her seven-member crew worked around-the-clock and, in a very real sense—although it would be another half-decade before the first permanent ISS crew reached their orbital home—they functioned for a short time as a “space station” in their own right.
However, as outlined in yesterday’s AmericaSpace history article, Columbia’s launch on STS-73 was a long time coming. Today, the flight holds the unenviable record of having tied with Mission 61C in having suffered as many as six frustrated launch attempts, before finally rising into space on the seventh try. In Commander Ken “Sox” Bowersox’s mind, their fortune may have turned on the most unlikely of dimes: wearing back-to-front baseball caps as they walked out of the Operations & Checkout (O&C) Building on the morning of 20 October 1995. “We were so desperate that last day that we decided to turn our hats around backwards,” he explained at the post-flight press conference. Describing the hats as “our rally hats”—and offering a nod to the baseballing tradition of wearing them as a lucky charm or to achieve a “come-from-behind” victory—Bowersox was convinced that it worked, “because we managed to launch.”
Equipped with the EDO hardware at the rear end of her payload bay, Columbia’s STS-73 mission was expected to be one of the longest shuttle flights on record. In fact, when the first members of the crew—Payload Commander Kathy Thornton and Mission Specialist Catherine “Cady” Coleman—were assigned in March 1994, it was expected to be the longest shuttle mission of all time, lasting 16 days, the peak of EDO baseline capability at that time. As the year wore on, the remainder of the crew was appointed. Payload Specialists Fred Leslie and Al Sacco were named in June and Commander Bowersox, Pilot Kent Rominger, and Spanish-born Mission Specialist Mike Lopez-Alegria joined them in November. However, the 16-day achievement was passed by the STS-67 crew in March 1995, raising the likelihood that, unless her own mission was significantly extended, STS-73 would come in as the second-longest shuttle flight at that time.
On the back of six fruitless launch attempts, the closeout crew at Pad 39B was startled by a fire alarm, just as they were strapping Bowersox and his crew into their seats on 20 October. However, there were no indications of a fire and, after a short delay, causing by a software glitch, Columbia rocketed into orbit at 8:53 a.m. EDT. From the flight engineer’s seat, Mike Lopez-Alegria described it as “the ride of your life” and, soon after achieving orbit, he and Coleman set to work opening the shuttle’s payload bay doors and deploying the radiators and Ku-band antenna. Due to the nature of their mission—which included a range of highly-sensitive microgravity experiments—Columbia would orbit the Home Planet in a “gravity gradient” attitude, with her tail pointing Earthward and her port-side wing in the direction of travel. In order to minimize the risk of Micrometeoroid Orbital Debris (MMOD) strikes on the delicate radiator panels, the port-side payload bay door was positioned at 62-degrees-open.
After that, Coleman, Lopez-Alegria, and Leslie—who formed the “night shift,” or “Blue Team”—came to the end of their first work day and bedded down for a few hours’ sleep. Coleman later remarked that going to sleep so soon after launching into space was “probably the hardest thing we had to do the whole mission, because I just can’t tell you how exciting ascent was.” In the meantime, the “day shift,” or “Red Team,” of Bowersox, Rominger, Thornton, and Sacco set to work activating the Spacelab module. Wearing her “lucky” red-and-white socks and U.S. baseball cap, and with checklist in hand, Thornton opened the hatches between Columbia’s middeck airlock and the tunnel leading to Spacelab. Fortunately, none of the crew suffered from space sickness and were able to hit the ground running for what was shaping up to be an ambitious mission.
On the afternoon of 25 October, Bowersox opened the port-side door for about an hour to provide sufficient clearance for a waste water dump from Spacelab’s condensate tank. Such dumps, which occurred through a nozzle on top of the module’s forward end cone, had to be performed every few days to get rid of water from the dehumidifiers. After completing the operation, Bowersox returned the door to its 62-degrees-open position.
It was already common practice on research missions of this type for the crew to work in two 12-hour shifts to maintain operations around-the-clock and, like USML-1 before it, the two Payload Specialists were world-class scientists in their field. Al Sacco had developed several of the mission’s zeolite crystal growth investigations, whilst Fred Leslie helped to design the Geophysical Fluid Flow Cell (GFFC) experiment, which was intended to mimic the dynamics of planetary and stellar atmospheres. “We’re primarily researchers and scientists,” Leslie said of the role of the Payload Specialist, “and the disadvantage is that often you only fly once.” The advantages, however, were that he received a flight assignment more quickly than “career” NASA astronauts. “I went into the program in 1994 and flew in ’95, so it was fast!” He also added that, since he was officially on U.S. Government Business, he received extra pay, but after transport and accommodation deductions, this amounted to just a couple of dollars per day. “You know the government,” Leslie grinned. “You can’t go anywhere without travel orders!”
As the mission wore on, Kathy Thornton took time to explain the importance of USML-2 for future ISS research. “This is a pathfinder for the kind of investigations we’ll have on the space station,” she told journalists during a space-to-ground news conference on 2 November. “There are very complicated experiments on-board, but they’re working beautifully.” For the first time, six-channel video footage from the experiments—which ran the gamut from fluid physics to crystal growth and from surface convection to combustion science—was relayed to the ground, via the High-Packed Digital Television Technical Demonstration (HI-PAC). This differed markedly from the single-channel video downlink previously employed on Spacelab missions and at one stage was even employed by the STS-73 crew to acquire live images of their colleagues sitting at their consoles in the Mission Control Center (MCC) at the Johnson Space Center (JSC) in Houston, Texas.
True to Thornton’s words, USML-2 was a real pathfinder for the ISS. And, indeed, four of the STS-73 astronauts would go on to play instrumental roles in the construction and operation of the ISS. Ken Bowersox and Mike Lopez-Alegria would both undertake a long-duration expedition, whilst Kent Rominger would command two ISS assembly missions and Cady Coleman would spend five months aboard the station in the twilight of the shuttle era.
The astronauts took time out at the midpoint of their mission to tape the ceremonial first pitch for Game Five of the baseball World Series. It was the first time that the thrower—in this case, Ken Bowersox—was not physically in the ballpark for the pitch. The video from orbit was replayed on the Jacobs Field Jumbotron screen in Cleveland, Ohio, ahead of the fame. Before throwing the slow-spinning pitch, Bowersox wished the Atlanta Braves and Cleveland Indians good luck. The crew flew baseball caps for both teams and subsequently signed their space-flown baseballs and donated them to Major League Baseball to be enshrined in the Baseball Hall of Fame in Cooperstown, N.Y.
Early on 5 November 1995, the Spacelab module was shut down and the hatches closed. Bowersox and Rominger fired Columbia’s Orbital Maneuvering System (OMS) engines at 5:46 a.m. EDT to begin the hour-long hypersonic descent towards the Shuttle Landing Facility (SLF) at the Kennedy Space Center (KSC) in Florida. As its trademark twin sonic booms echoed across the marshy landscape, the shuttle entered the Heading Alignment Circle (HAC) in the moments after local sunrise, descending at an 18-degree glide slope—six times steeper than a commercial airliner—and alighting on Runway 33 at 6:45 a.m.
“Sox just had the guidance nailed, doing a beautiful job,” recalled Kent Rominger in the post-flight press conference. “And it’s very dynamic. It’s like trying to land a bomb, because this was the middle of a bombing profile you fly in the Navy. I got the gear out at 300 feet (91 meters), we came across the threshold right where we should have been, touched down 2,500 feet (760 meters) down the runway and the landing was so smooth. It’s uncharacteristic of a Navy pilot,” Rominger said to audience laughter, “but this landing was so smooth that it was like an airline landing where … everybody just claps and cheers.”
All told, STS-73 had lasted 15 days, 21 hours, 52 minutes, and 22 seconds, wrapping up Columbia’s longest flight to date, the heaviest landing weight to date, at 230,400 pounds (104,500 kg), and the second-longest mission in shuttle program history at that time. In fact, STS-73 still stands as the fourth-longest flight in the entire, 135-mission shuttle era. To be fair, Rominger—who went on to fly the longest mission in shuttle history, later in his career—would have liked to have remained in orbit another day on STS-73, to capture the record from the STS-67 crew.
But it was not to be. And Rominger’s own admission, he had brief trouble with his balance in the early hours after returning to terrestrial gravity.
“If I had to take a drunken-driving test, hoe-to-teel … er … toe-to-heel,” he corrected himself, “I probably wouldn’t have done very well on that!”
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 upcoming 30th anniversary of Mission 61A, the last successful mission by shuttle Challenger and the only spaceflight to launch and land with as many as eight crew members.