In 1982, Soviet cosmonaut Valentin Lebedev spent 211 days aboard the Salyut 7 space station, and the diary he kept became a cautionary tale. Psychologists who read it say it was clear he was suffering from depression.
"Five months of flight," he wrote one day. "We don't feel time anymore. It's getting more difficult now. I begin to count the days. I've never done it before. I think our fatigue grows because our interest in work is fading. I don't even want to look out the porthole anymore."
Lebedev said he was irritated by questions from mission control -- even when they asked nothing more than "How do you feel?" He became testy with his one crewmate, and at times, the two stopped talking. His sleep patterns were a mess.
If things were that difficult on a flight just a couple of hundred miles from the Earth's surface, how will explorers hold up on longer flights, perhaps to Mars -- where there is no option of returning to the ground if things become intolerable?
Psychologists want to get a grip on these issues now -- long before astronauts actually go.
"It's not so much depression as that you're under a lot of stress," says Marc Shepanek, a psychologist at NASA. "You're in a strange environment, you're concerned about radiation, you're in microgravity. They're hard on your body, hard on your health, hard on your immune system."
"The conditions of expeditioners to Mars will be very different from those of today's relatively comfortable space (or polar, or undersea) enclosures in constant touch with 'home,'" says Peter Suedfeld of the University of British Columbia, who gave a presentation Thursday at a meeting of the American Psychological Association.
"Most of the time, Earth will be very far away, out of sight and without easy, rapid communications. The crew will face novel physical and psychological challenges without outside help."
James Carter, a psychologist at Harvard Medical School, is working on an interactive computer program called Virtual Space Station. With help from 13 American astronauts who have flown on long-duration flights, Carter's team is designing the program so that if an astronaut is suffering from depression or anxiety, or having a conflict with a crewmate, he or she can use the computer for therapy.
The hope, say Carter and his colleagues, is that if astronauts run into trouble, they can get help without the stigma of having called mission control to ask for it. Astronauts, who know medical problems can end their careers, have historically been reluctant to report them.
"It's the equivalent of psychological first aid," says Shepanek. He adds that flight surgeons are now very strict about protecting astronauts' privacy, so that they can seek help without fear of repercussions.
On the positive side, Space Station astronauts have reported the station cabin began to feel like home when they went for long-duration flights. They decorated the walls with flags and pictures, got presents whenever a supply ship arrived, and had regular, private video contact with their families.
In 2007, when astronaut Dan Tani learned during flight that his mother had died in a car crash, he was able to complete the mission. He later said hard work and the support of his crewmates were good therapy.
Even after the loss of the shuttle Columbia, NASA says space station astronauts held up well. Because of the lack of shuttles to bring adequate supplies, crews -- arriving on Russian Soyuz ships -- were reduced from three to two. But flight surgeons said astronauts talked to the ground more often -- in effect, letting mission control become the extra crew member.
Some of those options would be impossible on a Mars flight. Because of the distance, radio transmissions -- even traveling at the speed of light -- would take several minutes to go each way, so there could not be back-and-forth conversations with Earth.
A round-trip Mars flight, Suedfeld writes, "will be marked by stretches of empty time punctuated by bursts of hard, intense work; two very long voyages with the crew cooped up in limited space ... and the knowledge that home is far away, communication is slow and sometimes, perhaps, disrupted, danger is constant, and outside help in emergencies is unlikely."
And Shepanek agrees the stakes are high. "Even though the probability of a serious problem is very, very low, the consequences can be tremendous."
He cites the example of an Antarctic expedition member who became severely depressed -- and burned down the cabin he shared with his teammates.
But doctors have learned, they say, since the days when cosmonaut Lebedev hated to look out the window at home.
"The best outcome," says Shepanek, "is that you never hear about any serious problems."