🚀 go-pugleaf

tes@nomad.uucp (Thomas E. Smith [LORAL]) writes:

>|>> >     Today Mars Observer is about 4.5 million kilometers (2.6
>|>> >million miles) from Earth, traveling at a speed of about 10,800
>|>> >kilometers (7,600 miles per hour) with respect to Earth.  The
>|>> >spacecraft is traveling at a heliocentric velocity of about
>|>> >119,000 kilometers per hour (74,000 miles per hour).
>|>> 
>|>> Only 7,600 mph relative to Earth? Is that right? That's not even escape

This must of course be added to the Earth's velocity (vector addition) to
get the velocity relative to the Sun, which is MO's orbital velocity. And, 
as you got in response, this is the velocity left over AFTER escaping 
Earth's gravity.

Exercise :-) : Calculate MO's velocity relative to Earth when the MO was
  leaving Earth's atmosphere/LEO [Hint: Use energy conservation] !
[Solution: 11.49 km/s = 41,350 km/h = 25,850 mph 
  at R = 6,500 km (h = 120 km) ]
(BTW: *was* MO in a parking LEO, or was it launched directly into the 
  transfer orbit ? )

--
 Hartmut Frommert                 <phfrom@nyx.uni-konstanz.de>
 Dept of Physics, Univ of Constance, P.O.Box 55 60, D-W-7750 Konstanz, Germany
                                           -- Eat whale killers, not whales --