Mission planners at all the five space agencies involved in controlling the International Space Station (ISS) are currently juggling with the sleep schedules of all 9 astronauts left on the orbital lab. The most difficult task is achieving the perfect balance between getting enough rest and not wasting time.
In low-Earth orbit, time passes by a lot differently than it does on the surface of the planet. Astronauts experience more than 15 sunrises and sunsets per day, as the station travels above the entire world.
Traveling to space, such as for instance aboard the space shuttle Endeavour is similar to flying halfway around the globe, in terms of jet lag. Yet one of the greatest challenges is getting the orbiter's crew to match sleeping schedules with the three astronauts that now remain in the ISS Expedition 28 crew.
Doing so called for some pretty interesting maneuvers, mission planners revealed. Astronauts had to go to sleep at the weirdest hours of the day and night, in order to get up in time to carry out their allotted tasks and chores.
Since Endeavour docked to the station, on May 18, astronauts have carried out two spacewalks, installed the $2 billion Alpha Magnetic Spectrometer (AMS) particle detector, unloaded supplies, spare parts and personal items from the shuttle's cargo bay, and talked to the Pope via telephone.
Yesterday evening, half of the Expedition 27 crew climbed into their Soyuz space capsule, and then returned safely to Earth, leaving behind only 3 of their colleagues. This is the backbone of Expedition 28. The other three members are scheduled to arrive around June 7.
“The sleep shifting is specifically designed to match the hours that they need to be awake to support undocking and landing in Kazakhstan on Monday,” Rob Navias told Space yesterday.
“When Endeavour's mission moved into the time frame of the Soyuz departure, the flight control teams, in concert with the Russian side and ISS program, worked with flight surgeons to identify common ground where they could have the shuttle crew up and working when they needed to be up and working, and vice versa for the departing Soyuz crew,” the NASA spokesman added.
Most of the changes that took place in astronauts' sleeping programs were caused by preparations for the departure of the Soyuz capsule. The Soyuz spacecraft carried Italian astronaut Paolo Nespoli, of the European Space Agency (ESA) and NASA astronaut Catherine Coleman.
The crew was led by former Expedition 27 Commander, cosmonaut Dmitry Kondratyev, of the Russian Federal Space Agency (RosCosmos). The trio took a moment after separating from the ISS, to image the station with Endeavour attached to it for one last time.
“As far as the [sleep] overlap goes, its different from what we've done in the past, and we have to do it to support the Soyuz undock mid-mission, 'cause you've got the Soyuz landing on one side of the planet, and then the orbiter's going to want to land here in Florida on the opposite side of the planet less than a week later,” Gary Horlacher explained.
“To make that work, you have to have this overlap going on. So it is a little different than what we've done in the past, but it's not significant,” concluded the NASA official, who is the lead shuttle flight director.