Space Travel Challenges
For mankind, the adventure began at 9:07 a.m. Moscow time on April 12, 1961. A Soviet air force major named Yuri Gagarin blasted into the Siberian sky aboard a five-ton spacecraft and the world marvelled at the astounding news that he had landed safely after circling the Earth in just 108 minutes. Three weeks later, while Americans still smarted from having been left behind in the space race, Mercury astronaut Alan Shepard was lobbed 116 miles into the air from Cape Canaveral, Fla., and was slam-dunked into the Atlantic Ocean 15 minutes later. In the 35 years since, the United States alone has dispatched more than 500 astronauts, including five Canadians, on 110 missions into space, each more sophisticated than the last. To accomplish that, NASA has depended on technology to build more powerful, versatile and durable spacecraft.
But now, approaching the threshold of interplanetary travel, the agency faces a more formidable challenge: finding a way for fragile man to survive far longer stays in space. "It is clear," says Dr. Alan Mortimer, the Canadian Space Agency's director of life sciences, "that a whole series of questions related to long-duration stays in space haven't been answered." Those perils are numerous and little understood. Some are deadly and at this point insurmountable. But with the multi-nation assembly of the International Space Station scheduled to begin next year and the prospect of a Mars mission early in the next century, scientists in the United States, Russia, Canada and other countries are collaborating in a search for solutions. "There was a bit of a wake-up call when long-duration stays in space started," says Mortimer, "and now there's considerable interest in assuring that we have the information we need."
Some of the more urgent questions:
Why does the body lose muscle mass and vital bone calcium in long-duration space flights?
When the space shuttle Atlantis landed at Cape Canaveral on Sept. 26, astronaut Shannon Lucid, 53, who had spent a U.S.-record 188 days in space aboard the Russian space station Mir, was so weak she had to be supported by her crewmates as she walked unsteadily to a waiting stretcher.
How can space travellers be shielded from the sun's lethal radiation?
Even at Mir's altitude of 245 miles, there is enough atmosphere to provide radiation protection. But a return trip to Mars - anywhere from 34 to 62 million miles from Earth depending on where they are in their rotations - would take a crew into hazardous space for between two and three years, Mortimer says. At a guess, he adds, the cumulative radiation would reach critical levels for humans just two to three months after leaving Earth.
How will astronauts react to boredom, isolation and living at close quarters during long stays in space?
American astronaut John Blaha, who took Lucid's place aboard Mir on Sept. 18, will take part in first-time psychological experiments.
What are the implications of disrupted sleep patterns for long-term flights?
Russian cosmonauts, some of whom stayed aloft for a year and more, might have provided useful clues. But ground controllers apparently got little data from their sleep patterns and, besides, the cosmonauts took sleeping pills, which would have skewed the results anyway. (American astronauts have taken them as well, but the longest of NASA's 78 shuttle missions since 1981, last summer's flight by Columbia, was only 17 days.)
Of all the questions, some of the most critical for human health and performance in space revolve around sleep. Earlier this year, NASA embarked on the search for answers by assembling three teams headed by world-class scientists in that field - Dr. Harvey Moldofsky, director of the University of Toronto Centre for Sleep and Chronobiology; Dr. Robert Stickgold of the Harvard University medical school in Boston, and the University of Pittsburgh's Dr. Timothy Monk.
Their teams will investigate, among other things, the suspected link between sleep and the immune system, what happens in space to the body's 24-hour-based biological clock, and whether sleep will be disrupted enough to impair performance. Humans, including their programmed sleep patterns, have evolved according to conditions on Earth, says Stickgold, a neurobiologist, but those conditions do not exist in space.
The assault on the mysteries beyond the stratosphere has already begun - on the ground. Last August, six astronauts and cosmonauts who will spend four months aboard Mir next year gathered at NASA's Johnson Space Center in Houston for batteries of tests that will provide a baseline for comparisons with what happens in space. They recorded blood chemistry, sleep and dream patterns and how the body's various internal rhythms changed from day to night. The Americans will embark for Mir on Jan. 12 on the shuttle Atlantis, with the Russians riding a Soyuz spacecraft to join them in February. Six shuttle missions will follow and the crew of the seventh, to be launched on Dec. 4, 1997, will assemble the first chunk of the International Space Station.
When it is completed in June, 2002, the station will have as much living space as a three-storey mansion. But long before then, the three scientific teams hope to have clarified and reduced the risks of life in space. "How safe is it going to be up there?" wonders Moldofsky. "We know the hazards of getting up there, but what are the hazards of living there? Here are people who are out there circling the globe and having night and day every 90 minutes." Blood samples taken from previous astronauts, he says, showed evidence that their immune systems, which not only protect against disease but are involved in regulating sleep as well, had somehow been weakened, although no one knows why. "We do know that stress will impact on the immune system," Moldofsky says.
The implications of all that, he says, are sobering. Space travellers, whose immune systems may be compromised by stress and inadequate sleep, take along their Earth environment - "bugs, all kinds of bacteria. And so what's happening to these microbes? What's happening with them being bombarded by radiation? And what's the risk of disease and infection? This is where our study comes in." In addition to that, he adds, "the nervous system has to become attuned to the absence of gravity, which also has an impact on metabolism - calcium seems to leak out of the bones but, again, nobody knows why."
Similar puzzles confront Stickgold and Monk. The Harvard group designed an electronic nightcap that will chart an astronaut's sleep cycle at different times on consecutive nights. "We're going to get to see what sleep in space really looks like and whether it's disturbed and whether it recovers," says Stickgold, "because if you start curtailing it by just an hour and a half a night, you build up a sleep debt that's very destructive to your functioning." Even though a sleep-deprived individual may appear to be normal, "everything starts a slow slide that can be very subtle and very disastrous," he adds. "It would be unconscionable to send an expedition to Mars without confidence that their sleep is going to be adequate. And we don't have any evidence so far that it would be."
But while science knows the consequences of not getting enough sleep, it does not understand why we have to sleep in the first place. Stickgold thinks its purpose is probably to give the brain, freed from daytime distractions, a chance to adapt and learn from waking experience. "There's a lot of adaptation going on when you go into space, kinds that we can't even imagine yet," he says. "The question is, how much is sleep an integral part of that adaptation?" Dreams may furnish insights. Stickgold says astronauts and cosmonauts will be given microcassette recorders to describe their dreams, "because something unusual is happening." One cosmonaut, says Stickgold, reported: "All my dreams are in space; from the day I get up there until the day I get back, there's never gravity, I'm never on Earth."
And according to Pittsburgh's Monk, Star Trek-like dreams may not be the only phenomenon that divorces man in space from his earthly origins. Monk's team will test a hypothesis that on the space station the human biological clock will have a rhythm of from 24.3 to 24.4 hours instead of the 24-hour routine of life on Earth. During those intervals when the space and Earth rhythms are momentarily in phase, he says, everything is fine. "But when they're out of phase, we think that sleep may be disrupted and daytime moods and performance impaired."
Monk says adequate sleep may be the only way to avoid irritants such as boredom and sharing limited accommodation for long periods. "One of the first things that goes is congeniality," he says. "Also in space there arises an us-versus-them mentality - 'we're up here trying to get everything done and you guys on the ground won't leave us alone long enough to get it done.' "
The discussion of sleep in space leads all three men to broader speculation. Moldofsky wonders if there are ramifications to the fact that people become taller in space because, lacking gravity, the spinal column expands. Both he and Stickgold wonder how to resolve the problem that occurs in long-duration flight when the inner-ear balance mechanism becomes useless in zero gravity. "What NASA is worried about," says Stickgold, "is that until they hit the atmosphere, these guys are flying weightless and have lost their ability to tell up from down." The sense of weightlessness could become so profound, he says, that people might not even believe what their eyes are telling them when they have to assume the controls of a landing space shuttle under the force of gravity. "If we want to get serious about space flight, we have to solve these problems," says Stickgold.
And with some urgency, says the Canadian Space Agency's Mortimer. "Starting the program with Mir all of a sudden brought the future very close, very quickly," he says. "Even five years ago, it wasn't predicted that there would be Americans spending six months in space." But on the track to the space station and beyond, there may be dangers greater than any faced by record-setting Shannon Lucid, Mortimer says. One - "which we haven't addressed in any serious way" - is the psychology of isolation. "Human performance in confined areas," said Mortimer, "may turn out to be a significantly limiting factor."
As for radiation, he says, "we have to determine what the safe levels are and how we can reduce the damage from radiation because we can't send somebody to Mars in a big lead box." But the challenge of trying to get there is enough to stir the imagination of a scientist. "The whole idea is for the nations of the world to collaborate in using the space station as a springboard to other worlds," says Moldofsky. "The dreams of our childhood."
Maclean's October 14, 1996