Shuttle Orbited in Flight to Study Weightlessness

The space shuttle Columbia blasted through a hole in the clouds Wednesday on a biomedical research mission and gave space officials a taste of the success they once knew so well.

The space plane had to wait an hour and a half for the small gap in an extensive cloud layer to widen and drift over the launching pad. The sound of the thunderous journey into space provided officials, who feel under attack from every direction, a brief escape from their troubles.

“I just wish I were on board,” Richard H. Truly, head of the National Aeronautics and Space Administration, told reporters at a press conference.

The Columbia’s nine-day mission could rewrite the textbooks on the effects of weightlessness on humans in space.

Its crew of seven includes three medical doctors and two scientists, plus 29 rats and about 2,500 tiny jellyfish that will be cut up after the mission to see how they were affected by the sudden deprivation of gravity.

“We began to get data two hours after the mission began,” said Ronald White, program scientist at NASA headquarters.

The twice-delayed launching could not have come at a more important time for NASA, which has been stricken by various technical failures and is fighting to save Space Station Freedom from the congressional ax. The fate of the station hangs by the thinnest of threads, and Truly said the future of NASA is “unthinkable” without it.

As the fight to save the station continued in Washington this week, the shuttle remained on the launching pad with several technical problems. But, at 6:25 a.m. Wednesday, PDT, the space plane was able to climb into orbit.

One member of the crew should have been especially happy to get the liftoff over with. Francis A. (Drew) Gaffney, 44, a cardiologist, became the first man to travel into space with a catheter inserted through a vein in his arm and threaded to a position near his heart.

The catheter allowed scientists to measure changes in his cardiovascular system during the launching and for the first four hours of weightlessness. It was inserted a few hours before the scheduled launching Friday, but that liftoff was scrubbed. Rather than go through the process all over again, Gaffney left it there for five days, until after Wednesday’s successful launching.

The crew of the Columbia includes two other medical doctors, James P. Bagian, 39, and Margaret Rhea Seddon, 43, plus two research scientists, Tamara E. Jernigan, 32, an astrophysicist, and Millie Hughes-Fulford, 46, a chemist. Bryan D. O’Connor, 44, is the commander and Sidney M. Gutierrez, 39, is the pilot.

The data that Columbia’s crew will collect during the mission is expected to help scientists understand the profound influence of gravity on living organisms. The rats will allow scientists to study tissues to see how bones and muscles respond to the near-zero gravity of orbital flight. The jellyfish could help them learn how gravity makes it possible for an extremely simple nervous system to maintain balance.

The crew members also will serve as test subjects as they carry out 10 experiments using their own blood, urine, saliva and breath to analyze how their bodies respond to the loss of gravity.

Although flights of short duration are thought to cause only temporary problems for astronauts, no one knows yet what would happen during a long spaceflight such as a three-year trip to Mars and back.

“We don’t know today the limits, the threshold,” that humans can safely endure, said Arnauld Nicogossian, director of the life sciences division at NASA headquarters.

It may be, for example, that, even if humans can survive prolonged exposure to weightlessness, they may never be able to fully readjust to gravity after their return.

This mission is not long enough to answer that question, but scientists believe the experiments will help them understand what happens during what may be the most crucial period: the first exposure to weightlessness.

“We have to focus on a certain phase of change,” White, the program scientist, said. “We want to understand why things are happening” as members of the crew adjust to sudden weightlessness.

Weightlessness affects crucial aspects of the body--the heart, the lungs, bone growth and structure and, possibly, even the ability to resist disease. When a human, for example, is suddenly deprived of gravity, the fluids that normally pool in the feet and lower body rise to the upper torso. Sensing fluid overload, the body immediately begins discharging fluid from every pore.

One immediate effect is an increased heartbeat, but other changes are less obvious. On the Earth, muscles in the legs work against gravity to push blood up; in space, that function is no longer needed. And muscles in the lower back that help a person remain erect, despite the pull of gravity on Earth, also are unnecessary. These muscles, so critical on the ground, immediately begin to atrophy.

Robbed of gravity, the body no longer senses, quite literally, which way is up. Humans tend to become disoriented, which frequently results in space sickness, although that usually disappears in a few days.

Meantime, the number of red blood cells drops, as does the level of certain infection-fighting white blood cells. Bones begin to lose calcium and muscles lose strength as the body struggles to adjust to a radically altered environment.

Yet, miraculously, it does seem to adapt. Scientists want to know how it does so, not only for the future of space exploration but because so many afflictions that the body suffers temporarily in space are similar to diseases on Earth. Hypertension, heart failure, bone diseases such as osteoporosis and various muscle disorders are extreme manifestations of what everybody goes through in space.

Eighteen experiments are to be carried out by the crew for scientists on the ground. Here are some of them:

Cardiovascular deconditioning--Astronauts will “rebreathe” their exhaled breath while resting and pedaling on an exercise bike. By analyzing their breath, investigators will be able to determine how much blood is being delivered by the heart to the body during spaceflight. The experiment will measure cardiovascular and respiratory changes, including the amount of blood pumped out of the heart, oxygen usage and carbon dioxide released by the body, heart contractions, blood pressure and lung functioning.

Space sickness--Crew members will put their heads in helmets with rotating domes that will make them feel as though they are spinning, and that will cause them to rotate their bodies in the opposite direction. They will also be blindfolded and asked to describe the position of their limbs. The investigators want to know how such things as eyesight and tactile feeling influence space sickness and a person’s ability to maintain a sense of direction. Gravity helps animals maintain their orientation through small, calcified “gravity receptors” in the inner ear, but in space that sense of direction is lost. The receptors in the rats will be studied after the flight to see if they changed structurally during the mission. The jellyfish will also be killed and studied to see how their gravity receptors were affected by the flight. The jellyfish aboard Columbia are just old enough for their receptors to form during the flight, and they must be very sensitive because the jellyfish’s natural environment, the sea, is similar to the weightlessness of space.

Lymphocyte proliferation in weightlessness--One type of white blood cells, lymphocytes, collected 12 hours before launching, will be suspended in a substance that promotes cell division. Some of the samples will also be exposed to varying gravity levels on a low-gravity centrifuge aboard the shuttle. Other samples will be taken from the crew during flight. Investigators hope the results will tell them how much of a role gravity plays in reproducing white blood cells, a critical factor in fighting disease.

Red blood cells--Previous spaceflights have consistently resulted in a decrease in red blood cells and a subsequent reduction in the capacity of the blood to carry oxygen. Blood samples taken before, during and after the flight will show the rate and timing of production and destruction of red cells.

Calcium loss during spaceflight--Changes in calcium during spaceflight appear to be similar to changes caused by osteoporosis, a condition in which bone mass decreases and the bones become porous and brittle. Why that should occur during spaceflight is of great interest because it could severely affect the ability of astronauts to function after a long flight, such as a trip to Mars. For the first time, scientists will measure the levels in astronauts of hormones that stimulate cells that use calcium to produce bones. It is believed the level of hormones may change within hours of launching. A more direct measurement will come from the rats. Specific bones such as the leg, spine and jaw will be analyzed to determine changes in bone growth during the flight and whether bone formation returned to normal levels after the flight.

The Columbia is scheduled to land June 14 at 8:33 a.m. PDT at Edwards Air Force Base, Calif.