“Virtually all research data for ISS are based on regular six-month missions. It is important that we continue to collect data at these intervals so that we can begin to draw statistically significant conclusions [from a significant sample size],” says Leroy Chiao, who commanded a 6.5-month mission to the ISS in 2004-05 and currently chairs the National Space Biomedical Research Institute's (NSBRI) user panel, a group of 20 former flight surgeons and astronauts that assesses research on space health issues.
The source of the blurred vision issue and an effective countermeasure, a new NSBRI focus, are among the issues in need of a significant sample size, he notes.
“A one-year mission would have some value,” Chiao says. “Data could be used to compare to extrapolations made from six-month flights.”
Russians account for all four space missions of a year or more, each flown on Mir between 1987 and 1999. Since then, the ISS has greatly advanced opportunities for peer-reviewed medical research, a factor in Russia's enthusiasm for undertaking at least one more marathon flight while the ISS is in orbit.
“We would like to renew this experience,” says Alexey Krasnov, director of piloted space programs for Russian federal space agency Roscosmos. “The time is short. There are many things we don't know in spite of the fact that we have a lot of experience in spaceflight.”
Kelly and Kornienko will face twice the usual 7% chance that one of them will require a minor or major medical intervention during their flight, yet another opportunity for lessons learned, according to Ushakov.
Nonetheless, Avdeyev; Vladimir Titov and Musa Manarov, who ended a 366-day stay on Mir in late 1988; and Valery Polyakov, who completed a world-record 438-day mission to Mir in 1995, are alive and well.
“Their health status is quite good for their age,” says Ushakov, whose institute keeps up with their status. “So, the flights that happened 13-24 years ago did not negatively impact their health.”
Kelly's three space flights include a 160-day ISS mission in 2010 in which he served as commander for much of the stay. Kornienko served as an ISS flight engineer in 2010. NASA expects to name a backup for Kelly within several months; Kornienko identified cosmonaut Sergei Volkov as his backup,