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Let Me Check My Schedule
From soccer practice to dentist appointments, most families use a large calendar to schedule all of their daily activities. Astronauts use the same type of schedule on the International Space Station (ISS) - more or less.

Called the Onboard Short-Term Plan (OSTP), it's a graph that shows what is happening and who is doing it at any give time on the Space Station. Fitting all the astronauts' activities into the graph isn't always easy.

"The more people on the Space Station at one time, the more complicated it is to plan schedules," said Lisa Holmesly, an operations planner who develops OSTPs for the crew's day and makes sure there are no conflicting schedules. Many variables have to be considered when laying out the schedule, including times the vehicle is in the dark or light, the various time zones for the ISS, for Mission Control in Houston, as well as times in Russia.

Some activities must be separated by a time lapse. Astronauts shouldn't exercise just before or after eating a meal, and they prefer not to schedule interviews after exercise.

Astronauts need time to prepare for EVAs in space.Image to Right: More time is set aside for spacewalks, which may last up to 6.5 hours. Credit: NASA

Space walks require several hours for preparation and time after the walk for recompression. Some activities require the use of high-data-rate antennas, which aren't always available for use since the satellites that bring the signal to the ISS may be out of range.

Holmesly said, "The most challenging part is coordinating the exercise times. Each crew member must receive 2.5 hours of exercise to maintain muscle tone and overall fitness. Arranging that around meals, projects and other required activities is tough."

The ISS involves many participating nations taking part in the planning. "It's a slow process," says Holmesly. "The Russians have been working in space for years, and they have their preferences. The Japanese are newer to the program, and they bring different perspectives." With all of the languages, cultures and preferences, it takes tact and a willingness to cooperate to reach success.

Months before a crew launches into orbit, planners lay out the basic OSTPs for the entire mission. Once in orbit, astronauts and mission controllers modify the calendar on a week-by-week basis.

Astronauts prepare for a spacewalk.Image to Right: Astronauts work together to prepare for a spacewalk. Credit: NASA

Every week, astronauts and operations planners talk to lay out the schedule and make last-minute adjustments. While operations planners don't schedule experiments (that is done by a special team of payload planners), they work to make sure everything else is in order so these major events can proceed smoothly.

During discretionary time, astronauts often like to communicate with friends and family. E-mail is updated three times a day and anytime the Ku-band antenna is online, they can call down to Earth.

The process of scheduling astronauts' time has brought lots of data that will be used on longer-term missions, including the Moon and Mars, Holmesly says. "What we learn on ISS will directly help us for future missions. The OSTPs required for those will be monumental compared to what we deal with now."

NASA's new vision for space exploration establishes a timeline for the completion of the ISS, returning to the moon and eventual missions to Mars. The data collected from current scheduling will be a vital component to OSTPs for future missions and further exploration of space.

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NASAexplorers and NASA's John F. Kennedy Space Center