Scientists delight in ocean of data from Spacelab mission
Johnson Space Center, Houston — For 87 scientists and their colleagues, Christmas came three weeks early. Under the deft hand of shuttle commander John Young, Columbia and its six-man international crew glided gracefully to Earth late Thursday afternoon - the landing delayed by nearly eight hours due to computer problems aboard the orbiter. In its cargo bay sat the European Space Agency's Spacelab; at 16 tons, it's the heaviest payload ever returned on a shuttle flight.
During 10 days and more than 4.185 million miles in orbit, the instruments aboard the Spacelab returned 2 trillion bits of scientific data.
Of some 38 scientific instruments on board, only the microwave remote-sensing experiment failed to meet any of its major objectives. The device was silenced when its traveling-wave tube (the transmitter's amplifier) failed. Even so, its investigators were still able to collect some results.
Scientists were delighted. Spacelab 1 mission scientist Rick Chappell said at one point during the mission, ''Many of the scientists are as excited as kids with new toys. . . . You find them out in the hall collaring each other with the new results. And within the mission control room, you find them quite frequently in there with their data, showing it to each other.''
Dr. Chappell and Karl Knott, ESA project scientist, emphasize that the lion's share of the data is not available yet. Samples aboard Spacelab must be returned to researchers, some 20 million frames of video tapes must be distributed, at least 900 frames of film developed, and data from the Spacelab Data Processing Facility at the Goddard Space Flight Center in Greenbelt, Md., must be parceled out.
Chappell says the National Aeronautics and Space Administration (NASA) is holding discussions with Science magazine to devote an issue to reporting preliminary findings from experiments on this mission.
Although the data from this mission will require much further study, some early results were announced during the flight. Some of those include:
Life sciences. Rudolf von Baumgarten, a physiologist with the Johannes Gutenberg University in West Germany, may have pulled the rug out from under a 70-year-old Nobel Prize-winning theory of how inner-ear functions help humans maintain a sense of balance and direction. Increased understanding of this mechanism is expected to shed light on human adaptation to the weightlessness of space.
When warm air is blown into one ear and cooler air into the other, the subject feels as if he is about to turn. In response, the eyes move in the direction of the turn. Physiologists have attributed this to thermal convection in the fluids in the inner ear. But thermal convection is dependent on gravity. When this test was administered during the flight to payload specialist Ulf Merbold, he still felt the turning sensation. This registered in his eye movement.
''Because we got very strong eye flicks in space, and in space there is no convection in weightlessness, we now have to look back to the drawing board for another explanation of these flicks,'' Dr. Von Baumgarten says.
Many of the life-science experiments used mission specialists Owen Garriott and Robert Parker and payload specialists Byron Lichtenberg and Dr. Merbold as subjects. These four will remain at the Dryden Flight Research Facility at Edwards Air Force Base in California for an additional week, so researchers can conduct tests on the four men as they readapt to gravity.
Fluid physics. Scientists have been able to observe and record the behavior of lubricants in weightlessness, and they've monitored the action of fluids in partially filled containers. Both are expected to help in the design and operation of spacecraft.
Atmospheric physics. Using an instrument called the Grille spectrometer, Marcel Ackerman from the Institut D'Aeronomie Spatiale de Belgique in Belgium has observed carbon dioxide in the thermosphere (above 50 miles in altitude) and water vapor and methane in the mesosphere (between about 40 and 50 miles in altitude). In fact, his discovery of methane at that altitude prompted something of a debate in one of the planning meetings held during the mission.
Says Dr. Chappell, who was there, ''When Marcel reported that he had seen methane in the mesosphere, one of the other atmospheric physicists who was there said, 'There is no methane in the mesosphere. It's never been seen.' And Marcel said, 'Well, it has now!' ''
Other findings from Dr. Ackerman's spectrometer - such as detailed measurements of nitric oxide, nitrous dioxide, carbon monoxide, and hydrochloric acid at middle altitudes - are important to the study of the creation and destruction of ozone in the stratosphere. Ozone shields the Earth's surface from much of the sun's ultraviolet radiation.
These examples are just a smattering of the data that researchers will be poring over for the next few months and even years.
Divvying up the results of the experiments can be a bit of a challenge.
Stuart Bowyer of the University of California at Berkeley says that after his ultraviolet telescope ran out of film, his team and that of his French counterpart got into an argument over who would get first choice of photographs. But it was an argument with a twist.
''We insisted that the French take first pick, and they insisted that we pick first,'' he says. It took two flips of a coin and one more discussion before the French finally accepted first choice.
In addition to pursuing scientific objectives, some of the instruments used on this mission were turned on the shuttle and its environment to see how well the orbiter performs as a platform for space and earth observations. This mission was as much a test of the Spacelab module and its systems as it was a demonstration of the breadth of research possible using the lab.
The only major problems encountered with the Spacelab system were a balky black box known as a remote acquisition unit (RAU) and with the high data rate recorder (HDRR) in the lab. Mission engineers were able to work around the RAU problem, which seemed to crop up when the unit got too hot, and one of the crewmen fixed the HDRR.
Then, early Thursday, mission commander Young reported that one of the five general-purpose computers (GPCs) failed. Shortly afterward, a second unit failed. But later, the crew was able to bring the second unit back on line, and by reassigning tasks among the remaining GPCs, the flight was able to proceed to its late Thursday landing.
During this period, one of the inertial measurement units also failed. These devices supply on-board navigation computers with data on the orbiter's attitude and velocity. There are two more on board, which act as backups. Mission controllers merely had the crew switch to one of the other units.
At the time of this writing, NASA engineers still had not found the causes of the failures.
Despite these problems, the mission remained an unqualified success.
Overall, says Chappell, himself a co-investigator on one of the plasma-physics experiments, ''I think you really can't say enough good things about the Spacelab concept. In these 10 days we've seen the very successful merger of manned spaceflight and space science. The system is now set up so that the scientist, almost from his lab, can interact with his colleague, the scientist in orbit, utilizing the marvels of manned spaceflight, and do experiments that are just not possible any other way.''
If STS-9 illustrated the drama of manned spaceflight and science, the next mission, now dubbed 41-B (4 for fiscal 1984, 1 for launch from the Kennedy Space Center, B for the second flight of the fiscal year) will provide drama of another sort.
Set for a Jan. 30, 1984 launch, the shuttle Challenger will carry two communications satellites and the first manned maneuvering units (MMUs). During the eight-day flight, astronauts will don spacesuits and an MMU and conduct a series of flight tests for the 330-pound backpacklike propulsion devices.