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Answers Your Questions

From: Nicole, of Santa Barbara, Calif.,
To: Tony Ceccacci, flight director for the orbit 2 team

Question: How long does it take for the space station to circle the Earth?

Answer: It takes approximately 92 minutes for the ISS to complete each orbit. This time will vary based on the station's current orbit -- the orbit continually decays at a very small rate. The orbit is boosted periodically to account for this, so the orbit time is not constant.

If you need a more exact time, you can go to the NASA Human Space Flight home page ( and select Realtime Data, then go to Orbital Elements and choose the ISS orbital elements page. This page has data on an orbit-by-orbit basis. For a given orbit look for the "Mean motion", given in revolutions per day (rev/day). To convert the mean motion value into minutes per revolution for that orbit, divide it by 1440 (= 60 minutes/hour x 24 hours/day).

Kevin McCluney
Ascent/Entry Mechanical Systems

View a list of answered questions or ask MCC your own question.

Curator: Kim Dismukes | Responsible NASA Official: John Ira Petty | Updated: 06/16/2002
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