international space station ......
 

anyone know the average velocity of the I.S.S. ?

cheers ....

Average velocity = Zero. :p - 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...

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.

:rolleyes:

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 ......