The space shuttle Columbia hurtled into space today, carrying a medical laboratory that scientists hope will answer many questions about how humans adapt to shifts between gravity and weightlessness.
Embarking on the 58th flight of the shuttle program, the Columbia lifted off after an almost flawless countdown at 10:53 A.M. in ideal weather to begin a two-week journey planned to be the longest shuttle mission so far.
The shuttle, whose liftoff was delayed twice last week because of equipment malfunctions and bad weather, carried seven astronauts and 48 rats into an orbit 176 miles above Earth. Two hours after the launching, astronauts activated Spacelab, a 21,840-pound pressurized laboratory carried in the Columbia's cargo bay in which many of the medical experiments will be carried out. First Veterinarian in Space
Among the crew of five men and two women are two medical doctors, a biochemist and the first veterinarian in space, all trained to focus on life science and the regulatory systems that control so many body functions.
The mission, which continues research conducted on the first Spacelab Life Sciences mission in 1991, will examine how muscle, bone and other tissues, as well as organs that control balance and orientation, change during weightlessness and readapt when back under the influence of gravity.
For instance, two of the astronauts, Dr. Shannon W. Lucid, a biochemist making her fourth flight into space, and Dr. Martin J. Fettman, the veterinarian, rode into space with catheters snaked through an arm vein into their hearts to help measure changes in their cardiovascular systems as their bodies shifted to weightlessness.
Over the past 32 years, Americans have traveled into space 87 times, on flights lasting from 15 minutes to many weeks, allowing astronauts to adapt to near weightlessness during their missions and to readjust to Earth's gravity upon their return, NASA scientists said. But the reasons behind the physical changes, from decreasing bone and muscle density to lower blood volume, remain a mystery.
Dr. Frank Sulzman, the NASA science program manager, said more research on the physiological aspects of space travel must be done if humans are to work on space stations for months or years at a time, or travel to other planets. In addition, he said, the work should also give researchers a better understanding of how the body works or malfunctions on Earth. For example, they will try to determine how gravity helps muscle maintain its strength and tone, a problem for people with degenerative muscle diseases.
"Maintaining healthy bones and muscles can be better understood if we can remove the pervasive force of gravity," Dr. Sulzman said. "The things we learn in space on how living systems respond to weightlessness will help people on Earth."
Some of the more important experiments on the mission are to involve 48 white rats, the most ever carried into space by a shuttle. Like the more than 100 other rats that have ventured into space aboard shuttles, the ones aboard the Columbia are to be sacrificed after the mission so that researchers can examine their organs and tissues.
But for the first time, five or six of the rats on this flight will be killed in space so that scientists can preserve their tissues before they are subjected again to gravity. More than 100 scientists worldwide will use tissues from the Columbia's rats to compare their condition before, during and after time in space, Dr. Sulzman said.
Dr. Fettman, aided by Dr. M. Rhea Seddon, a doctor making her third space trip who is in charge of the medical experiments, will use a hand-operated guillotine common to laboratories on Earth to decapitate the rats late in the mission. The researchers, working in an enclosed glovebox, are to remove and preserve many organs and tissue for later study, including brains, inner ears, eyes, lungs, bone marrow, muscles, glands and major organs like the heart, liver and kidneys.
Some animal rights groups protested the experiments as scientifically unnecessary and cruel, but NASA scientists said the work, including the decapitations in space, was essential for understanding changes caused by weightlessness.
The 14-day, 23-minute mission would be five hours longer than any previous shuttle mission. In addition to the medical experiments, other studies planned for the mission include the testing of a portable flight simulator for shuttle landings. Dr. Charles R. Justiz, a NASA research pilot at the Johnson Space Center in Houston, working with a former astronaut, Joe H. Engle, designed a portable computer work station that contains some of the computer programs used in large flight simulators on the ground.