international space station ......
Average velocity = Zero. 
- if you're using Earth as the frame of reference.
Its speed can be calculated if the orbit height is known.
P= 2 Pi (a^3/u)^1/2
P: orbital period
a: the semi-major axis of the orbit (same as the radius of the circle for a circular orbit!)
u: gravitational parameter ( ~398601 km3 / Sec2 for Earth)
dist = 2 PIE r
r: orbit radius = orbit height + Earth's own radius
speed = dist / time = 2 PIE r / P
A shortcut:
For near Earth orbits, if distances are measured in Earth radii, the circular orbital speed is
Speed= 7.907 A^-½ km/s
A = units of Earth radii
This is because the speed inversely to the square of the orbit radius. At the Earth's surface orbital speed is 7.907 km/s
Edited because I can't spell 'Pi'.
Just discovered my g/f can though.
That's what I get for posting before lunch...
- if you're using Earth as the frame of reference.Its speed can be calculated if the orbit height is known.
P= 2 Pi (a^3/u)^1/2
P: orbital period
a: the semi-major axis of the orbit (same as the radius of the circle for a circular orbit!)
u: gravitational parameter ( ~398601 km3 / Sec2 for Earth)
dist = 2 PIE r
r: orbit radius = orbit height + Earth's own radius
speed = dist / time = 2 PIE r / P
A shortcut:
For near Earth orbits, if distances are measured in Earth radii, the circular orbital speed is
Speed= 7.907 A^-½ km/s
A = units of Earth radii
This is because the speed inversely to the square of the orbit radius. At the Earth's surface orbital speed is 7.907 km/s
Edited because I can't spell 'Pi'.
Just discovered my g/f can though.
That's what I get for posting before lunch...
Last edited by Tinstaafl; 16th Feb 2003 at 22:44.
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How high is up?
Way back when I worked on the Saturn Apollo program the key speeds for orbit and for lunar insertion were 18,000 MPH and 23,000 MPH respectively. I assume this still applies.
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during an intimate moment with the gal in my life, she asked me .....
"hobie, do you know how fast the International Space station travels?"
In a moment of inspiration I promised her that I would ask the guys on PPRUNE and hence my question .......
I had in mind a number around 18,000 mph and from the above answers it looks like its around this speed .....
ISS altitude info is available at .....
http://www.spaceflight.esa.int/users...c-iss-open-alt
cheers guys ......
"hobie, do you know how fast the International Space station travels?"
In a moment of inspiration I promised her that I would ask the guys on PPRUNE and hence my question .......
I had in mind a number around 18,000 mph and from the above answers it looks like its around this speed .....
ISS altitude info is available at .....
http://www.spaceflight.esa.int/users...c-iss-open-alt
cheers guys ......
