Posted by John on December 31, 1999 at 21:49:00:
In Reply to: Re: Speed of Hubble posted by Meat-pizza on December 29, 1999 at 12:34:48:
> > How fast were the astronauts moving while on the Hubble doing repairs.
> > Rumors have it that it was 4000 mph. Can you inlighten us?
>
> The astronauts actually move pretty slowly while they repair the telescope, if they moved at 4000 mph they'd have all their tasks done in a couple of seconds!
> Jokes aside, I think what you are asking was the relative speed of the shuttle and HST to someone standing on earth, which was about 17,500 mph (or 28,163 kilometer/hr for you metric fanatics). The relative velocity between the astronauts and the shuttle was zero (they were traveling at the same speed and direction), so they have really had no sensation of how fast they were traveling.
Hubble is orbiting at 590 km about the surface of the earth. The distance from the centre of the earth to the surface is 6370 km. Thus Hubble is orbiting 6960 km about the centre of the earth. The path length that Hubble travels around the earth is 2*pi*6960 km = 43 731 km.
It takes Hubble about 100 min to circle the globe. This calculates to about
26 239 km/h, rounding to the nearest whole kilometre. Thus the value you gave in both miles and kilometres per hour is about 2000 km/h on the high side. Obviously the speed in miles was rounded to give it the appearance of being a rational speed. Since the time of 100 min might not be exact, the speed I calculated could be off too. The 100 min orbit time came from the Hubble web page: http://hubble.gsfc.nasa.gov/discussion.html.
Does anybody know the exact time it takes Hubble to orbit the globe?
John