By CLAUDIA MILLER

When 77-year-old John H. Glenn leaves his chair in the United States Senate to climb aboard the shuttle Discovery for his historic nine-day flight into space, Oct. 29, he carries with him not only the hopes of a nation in search of heroes, but also the hopes of gerontologists looking for further parallels between the effects of space flight and aging.

One of the original Mercury astronauts, Glenn hasn't been in space since February 1962, when, at age 40, he became the first American to orbit the Earth. As a payload specialist aboard Discovery, he will conduct numerous experiments, including several focusing on problems faced by older adults: decreased functioning of the immune system, balance disorders, sleep disturbances, and bone and muscle deterioration.

PUBLICITY DRIVEN?

While Glenn will serve as a researcher for many experiments, he will also be a research subject. Scientists want to find out how his body reacts to being in a gravity-free environment for nine days: His heart rate, respiration, body temperature, blood pressure and other vital signs will be monitored around the clock and compared to pre- and post-flight results. When Discovery returns to terra firma, Glenn will be subjected to another round of medical tests so researchers can analyze any changes in his bone density and his spinal cord.

Former National Aeronautics and Space Administration (NASA) historian Alex Roland, who now chairs Duke University's history department, is among the critics who contend that Glenn's flight is publicity driven and is "misrepresented" as a scientific experiment. "Clearly, this flight will show us how John Glenn fares in space, not all 77-year-olds," Roland told Aging Today. "This is more of a victory tour for NASA, and I'm concerned that NASA will find itself once again encouraging the 'citizen in space' program, which I do not think is a good idea."

David Liskowsky, NASA Life Sciences Program Scientist for Glenn's STS-95 mission, counters that the senator's flight is "just the beginning of our broader look into understanding the effects of space flight. We have a good database of information on how a typical 30-to-55-year-old astronaut's body reacts to space flight, and this will give us some initial observational data of how a 77-year-old body reacts."

Liskowsky said the mission will help researchers use information already obtained from previous flights and apply it to aging issues. "We are working collaboratively with the National Institute on Aging to explore some of the parallels," he said.

"We understand that many of the outcomes of space flight are the same as those older adults face," Liskowsky added. "We are also focused on developing countermeasures to help astronauts lessen or alleviate the negative effects of space flight. As we develop those countermeasures, we hope some of them may have therapeutic results for older adults as well."

LIFE SCIENCES STUDIES

Glenn will serve as both a researcher and a research subject on a protein-turnover experiment, a NASA Life Sciences Program study designed to better understand how body chemistry changes during space flight. Scientists hypothesize that muscle breakdown in zero gravity occurs because of the release of stress hormones, resulting in a change in protein chemistry. Crew members will take nonradioactive amino acids (the building blocks of protein), which scientists can trace as they're processed by the body.

Glenn also will participate in a clinical trial testing melatonin as a hypnotic (sleep inducer) for crew members. Scientists want to know whether sleep disruption during space flight results only from the noise of the shuttle and related environmental factors or from disturbance in the body's biorhythms. In an attempt to answer this question, some crew members will ingest melatonin while others will take a placebo. For four nights, their sleep will be monitored with electrodes to measure brain waves or eye and muscle movements. Each day, astronauts will take cognitive tests to determine if those ingesting melatonin receive better scores than the control group.

Other experiments involving Glenn include an astroculture study of plants grown in a microgravity environment and a biotechnology dynamics study related to organ transplantation and to diabetes and other diseases associated with aging. He also will take pictures using the photo and television equipment aboard the orbiter.

Former NASA astronaut and bone researcher Millie Hughes-Fulford says studies of how Glenn reacts to being in space "will be a good data point that we need to set." She added that although he is not a typical older American, "we have to start getting data somewhere."

OSTEOPOROSIS RESEARCH

Hughes-Fulford flew aboard the shuttle Columbia in 1991, conducting research on osteoporosis. She is currently principal investigator and deputy assistant chief of staff at the Veterans Administration Medical Center in San Francisco, associated with the University of California, San Francisco.

She continues to research osteoporosis and bone cell structure, in particular how lack of mechanical stress affects bones. "That's one of the questions we have to answer," she said. "If one day we go to Mars, how can we have a rotating cycle of sleep and exercise to maintain the astronaut's bones properly?"

Hughes-Fulford said she is "thrilled that Glenn is going aboard the shuttle Discovery. I think this sends a wonderful message to the American people not to give up and think that just because you're over 60 and ready to retire, you have to quit doing everything."

Glenn, an Ohio Democrat, will retire this year after spending 24 years as a U.S. Senator. "Senator Glenn's interest in aging long predates his current involvement with NASA," stated William F. Benson, former acting U.S. Assistant Secretary for Aging. Benson said that Glenn, who hired him as a staff member of the Senate Special Committee on Aging in the early 1980s, "provided key support on issues from nursing home reform to Indian elders. He authored most of the 1987 amendments to the Older Americans Act that improved services to older American Indians."

When Glenn cochaired the Special Committee's June hearing titled "The Graying of Nations III: Productive Aging Around the World" (sessions Iand II were held in 1977 and 1985 respectively), he became one of the few people to have participated in all three sessions examining international developments in aging research.

Benson remarked, "I've known a lot of powerful people in Washington, but John Glenn is one of the most down-to-earth people I've ever met here."

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