97011B (Centaur) Observed
Philip Chien (kc4yer@amsat.org)
Mon, 5 May 1997 03:53:22 -0400
Ron Lee <ronlee@pcisys.net> said:
>97011B
>1 24749U 97011B 97115.05838735 .00174149 42521-6 16716-2 0 402
>2 24749 25.7514 42.7899 6062057 241.1488 45.9849 4.05482701 1905
>
>When looking at the orbital parameters for this object (about 159 x
>21032 km), it seems odd that it is not in a supersynchronous orbit.
>
>That raises the question on whether the payload (Tempo 2) is very
>heavy since the Centaur is designed to take a payload (TBD pounds)
>from low earth orbit to GSO.
In a rather unusual contradiction most current satellites to geosynchronous
orbit go to either very high apogees or very low apogees.
In some cases it's more efficient to load up the propellant tanks all the
way and have the rocket put the payload in to a lower orbit. Then the
satellite's on-board supply is used to raise the orbit and cancel out the
inclination.
In other cases a supersynchronous orbit is used where a very high apogee is
used. This minimizes the amount of inclination reduction which is
required, enough to make up for the altitude difference.
The many factors which come in to play include the satellite's mass, the
size of the propellant tanks and the planned lifetime. Some of the
parameters which can be tweaked include the inclination at deployment, the
apogee, and perigee.
The key reason for the wide variety of possibilities is most satellites are
being designed to work with as many different launch vehicles as possible.
Until the late 1970s a satellite was designed to work with a particular
launch vehicle. Then satellites were designed to be compatible with the
shuttle, but also capable of being launched on a Delta. Now satellite
manufacturers have to make satellites compatible with a wide variety of
launch vehicles from a wide variety of launch sites.
Philip Chien [M1959.05.31/31.145//KC4YER@amsat.org]