When scientists start conducting science experiments on board the International Space Station, they will be drawing on a heritage developed on 29 Space Shuttle missions that carried Spacelab, a reusable laboratory for space.
In the process, Spacelab brought together scientists whose diverse disciplines would have kept them from meeting but for one fact. Their experiments somehow made the right fit, or at least did not interfere, so they could fly together.
"The thing I enjoyed the most was the opportunity to work for seven years with really competent people," said Dr. Loren Acton, a payload specialist on Spacelab 2. Acton was then with the Lockheed Palo Alto Research Laboratory. He now is with the Montana State University in Bozeman.
"It was a pleasure to be part of a program where you could count on everyone. It was a wonderful experience to be involved in so many different fields of science." On his flight in 1985, Acton, a solar physicist, also worked on experiments in plant growth, vitamin D metabolism, and infrared, X-ray, and cosmic ray astrophysics.
Last week, NASA and the National Academy of Sciences held a two-day symposium "Spacelab Accomplishments Forum."
Spacelab was developed by the European Space Agency (ESA) in the 1970s and early '80s as its entry into manned space flight. When Space Shuttle development started in the early 1970s, NASA recognized that it needed a facility that would allow scientists to conduct research on the Shuttle while in orbit. A permanent space station was still several years in the future, and scientists wanted to expand on research and lessons from the Skylab space station.
At the same time, ESA wanted to become involved in manned space flight. After exploring several options, NASA and ESA agreed upon a modular research laboratory - soon called Spacelab - that would fit inside the Shuttle's payload bay. The two basic sets of hardware allowed scientists to conduct experiments inside - protected in a pressurized module - or outside - with instruments mounted on pallets exposed to space.
Building on its experience from the three-man Skylab space station (1973-74), NASA's Marshall Space Flight Center was placed in charge of Spacelab development and missions and, later, payload control during missions. Space Sciences Laboratory scientists would serve as mission scientists and as principal or co-investigators, and large teams would become involved in support roles during the missions.
Depending on the research planned for the mission, Spacelab could be assembled in a dozen arrangements, such as a long module with one pallet, a short module with three pallets, or four pallets and no module. In time, NASA, the Air Force, and industry developed other carriers for payloads that had unique needs that Spacelab did not meet, or that did not need everything Spacelab offered.
Nevertheless, from 1982 through 1998, Spacelab was the focal point for experiments conducted by Americans in space. Because the missions were limited in duration - 10 days, then 19 days with the addition of an energy kit - it was anything but a luxury cruise.
"It's kind of like a science marathon," said Dr. Fred Leslie, a materials scientist with NASA/Marshall. He was a payload specialist for the second U.S. Microgravity Laboratory (USML-1) in 1995.
"Once we unstrap from our seats after launch, there's a lot of things to do," Leslie said. These include helping the pilots stow launch plans and spacesuits, break out orbital plans, and handle other tasks for operations.
"That kind of sets the tone for much of the flight," Leslie continued. "Everything was scheduled to within 5-minute increments. I thought it was ideal because I enjoyed staying busy with experiments."
The first Spacelab mission was flown in 1983, but NASA already gained a little experience when it flew engineering models of Spacelab pallets on the second and third Shuttle missions in 1982-83. The pallets were not fully outfitted, and the flight crew had to divide their time between testing the Shuttle, their primary mission, and operating the experiments. Nevertheless, the mapping radar carried on STS-2 and the space physics and solar instruments carried on STS-3 showed tremendous potential.
The first true mission, Spacelab 1, was flown Nov. 28-Dec. 8, 1983, aboard Space Shuttle Columbia. In a mission billed as "science around the world and around the clock," the crew divided into two three-man shifts and worked almost continuously for 10 days. They grew the first protein crystals grown in space, scanned the chemical makeup of the atmosphere, measured radiation from the sun, and experimented with the behavior of fluids.
While the results from Spacelab 1 added to the expanding body of knowledge in space sciences, the protein crystal growth experiments would have a fundamental impact on health research. In their experiments, European scientists grew crystals that were larger and had more neatly ordered molecules than crystals of the same materials grown on Earth.
The implication was striking: without gravity's effects to pull them down into a mash resembling broken glass, large biological molecules could be grown for analysis by X-rays on Earth. This opened the potential for understanding the structures of proteins that tell viruses, bacteria, immune cells, and enzymes how to work. From this, scientists could develop drugs targeted for a specific function with few side effects. For example, NASA recently announced that such research for the Center for Macromolecular Crystallography in Birmingham, Ala., may lead to drugs the reduce the severity and duration of the flu.
In contrast to Spacelab 1's deliberate effort to demonstrate its utility to all aspects of science, the next two Spacelab missions were dedicated to specific disciplines. Spacelab 3 (March 1985) carried an array of materials science experiments and atmospheric instruments. Spacelab 2 (July 1985) carried instruments to study the sun, stars, and comic rays.
Spacelab 3 became an outstanding demonstration of how scientists can share resources across disciplines, and of the utility of people in space. Soon after launch, a major atmospheric spectrometer (ATMOS) ran into trouble. A laser that measured the changing position of key optics inside ATMOS developed a leak in its power supply. In a couple of days, the drop would allow electrical arcing that would short out ATMOS. The materials scientists agreed to defer many of their experiments so the Shuttle could maneuver and let ATMOS make its key observations right away instead of at the end of the mission.
Inside, payload specialist Taylor Wang was solving a different kind of power problem. One of three sound generators in his Drop Dynamics Module had shorted out, killing hopes of running experiments on how drops behave. Wang, who also was the principal investigator, got into his work - literally. He opened the rack containing the DDM and, working almost without a break, isolated the failure and rewired part of the DDM. Several dramatic pictures showed Wang with his legs sticking up in the air as the DDM rack appeared to swallow him. With the problem fixed, he worked non-stop to run nearly all of his experiments before the mission had to return home.
Following Spacelab 3 was Spacelab 2 with a cluster of solar telescopes on the new Instrument Pointing System plus X-ray and infrared telescopes and the "Chicago egg," a large cosmic ray detector from the University of Chicago. Although the sun and stars were the focus, Acton noted that the mission "was about as multi-disciplinary as you could imagine. One of the things we learned was that we tried to accommodate and carry out great a variety of experiments.
Spacelab missions went into hiatus, along with the rest of NASA's manned space program, following the tragic loss of Space Shuttle Challenger on Jan. 28, 1986. Shuttle flights resumed in 1988. In late 1990, ASTRO-1 started an increasingly hectic schedule for Spacelab. By the time the series ended in 1998, a total of 28 Space Shuttle missions had carried Spacelab hardware. Five missions used modified pallets to carry mapping radar and other instruments, and thus are not counted as true Spacelab missions. Of the remainder, 15 used the Spacelab long module to house scientists and experiments (the short module option was never flown) and eight used trains of two or three pallets to carry telescopes and other instruments.
ASTRO-1 and -2 carried a battery of three ultraviolet telescopes to observe the universe in light that is filtered out by Earth's atmosphere. A series of three Atmospheric Laboratory for Applications and Science missions (ATLAS-1, -2, -3) reflew atmospheric instruments and solar monitors from earlier Spacelab missions. By flying them together, scientists could calibrate atmospheric measurements made by unmanned satellites launched years earlier.
Several Spacelab missions were dedicated to the science of how materials behave in the microgravity environment of space: two International Microgravity Labs (IML-1 and IML-2), two U.S. Microgravity Labs (USML-1, and -2), Spacelab-J for Japan, Spacelab D2 for Germany, and Microgravity Sciences Laboratory-1 (MSL-1), a forerunner of how science will be conducted aboard the International Space Station.
Three Spacelabs focused on how life adapts to and changes in space: two Space Life Sciences (SLS-1 and -2) and Neurolab, the last mission to use Spacelab hardware. The Life and Microgravity Sciences mission (LMS) combined both fields. Spacelab has also been pressed into service as a supply carrier with pallets carrying replacement parts to the Hubble Space Telescope and supplies for the Mir space station.
With NASA concentrating on preparations for International Space Station - including a wide array of materials, life sciences, and physics experiments - Spacelab was retired in 1998. While the Spacelab missions were highly successful, they did require a large effort on the part of NASA's science and engineering teams. The hardware is being distributed to space museums, including the National Air and Space Museum in Washington, D.C.
But it leaves a distinguished legacy. Lessons about how to conduct science in a demanding and dynamic environment are shaping research on Earth and on ISS. Spacelab has become one of Isaac Newton's "shoulders of titans" on which future space scientists will stand as they shape the 21st century.
Space Shuttle missions carrying Spacelab or Spacelab hardware
(italics indicate pressure module, others used pallets)
- 1981
- STS-2 -- OSTA-1 (radar mapping; atmospheric science)
- 1982
- STS-3 -- OSS-1 (solar and space physics)
- 1983
- STS-9 -- Spacelab-1 (multidisciplinary)
- 1985
- STS 51-B -- Spacelab-3 (materials and life sciences)
- STS 51-F -- Spacelab-2 (solar, space physics; astrophysics)
- STS 61-A -- Spacelab D-1 (Germany; materials sciences)
- 1990
- STS-35 -- ASTRO-1 (ultraviolet and X-ray astronomy)
- 1991
- STS-40 -- Space Life Sciences-1
- 1992
- STS-42 -- International Microgravity Laboratory-1
- STS-45 -- Atmospheric Laboratory for Applications and Science-1
- STS-46 -- Tethered Satellite System-1
- STS-47 -- Spacelab-J (Japan)
- STS-50 -- U.S. Microgravity Laboratory-1
- 1993
- STS-56 -- Atmospheric Laboratory for Applications and Science-2
- STS-55 -- Spacelab D-2 (Germany)
- STS-58 -- Space Life Sciences-1
- STS-61 -- 1st HST servicing
- 1994
- STS-59 -- Shuttle Radar Laboratory-1
- STS-65 -- Space Life Sciences-1
- STS-68 -- Shuttle Radar Laboratory-2
- STS-66 -- Atmospheric Laboratory for Applications and Science-3
- 1995
- STS-67 -- ASTRO-2 (ultraviolet astronomy)
- STS-71 -- Space Life Sciences-1
- STS-73 -- U.S. Microgravity Laboratory-2
- 1996
- STS-75 -- Tethered Satellite System-1R (reflight)
- STS-78 -- Life and Microgravity Sciences
- 1997
- STS-82 -- 2nd HST servicing
- STS-83 -- Microgravity Science Laboratory-1
- STS-94 -- Microgravity Science Laboratory-1 (reflight)
- 1998
- STS-90 -- Neurolab
- 1999
- (STS-99 -- Shuttle Radar Topography Mission)