When an astronaut is orbiting the earth, how often does he see a sunrise or a sunset?

Question

this is extra credit for a class, but i cant seem to find the answer.

Answer 1

It depends on the hight of the orbit--the further up the slower the orbit. But at the altitude of the International Space Station (about 220+ miles--350 km) they circle the earth every hour and a half, more or less. So they see a sunries -- and then a sunset--every 90 minutes, or about 16 times a day.

Answer 2

In low earth orbit approximately at the equator your astronaut will see a sunrise about every 90-95 minutes or so.

There are, however, orbits inclined more than 90 degrees to the equator that are in a "sun synchronous" orbit, so that the motion of the earth beneath the craft, the motion of the earth around the sun, and the motion of the spacecraft itself, work hand in hand so that the sun is always in the same position relative to the spacecraft. No manned craft has ever had one of these orbits, but they are valuable for earth reconaissance and spying (they sun angle is always good).

The more an orbit is inclined to the equator the greater the difference in length of daylight and darkness (because of the tilt of the rotational axis of the earth). On Skylab there was a very high orbital inclination, so it came to be that orbits during part of the year were in much lengthier daylight than darkness (and at another time vice versa), and so there was a big difference in the time between sunrise and sunset versus sunset to sunrise.

Apollo astronauts on Apollos 8, 10, and 11-17 were launched on very elliptical earth orbits (which were perturbed by the presence of the moon and which allowed them to go into moon orbit). These radical orbits allowed for no sunrise or sunset en route. With the possible exception of one (maybe, and I don't remember which) none of the Apollos had quite the velocity necessary to "break out of earth orbit" completely: the need was just to get around the back of the moon and let the braking rockets get them into orbit. The so-called "non-return" flights were still flights in extremely elliptical earth orbits (with the exception mentioned above).

Answer 3

It depends on which direction he is traveling in, how long he's traveling, the starting time and where he starts and lands. If that's the full question, there is no definite answer.

Answer 4

Takes roughly 90 minutes or so.

Answer 5

every 30 minutes