Re: Supersynchronous

Jens Lerch (jlerch@geocities.com)
Tue, 29 Sep 1998 10:44:44 +0000

> >|>Anybody know what "supersynchronous" means?
> >
> >Exactly the above - ie place it in a transfer orbit far higher than
> >one would think needed - 140 x 54755km. Plane change maneuvers have a
> >lower penalty fuel-wise the further you are from the primary body - thus
> >a supersynchronous delivery to geostationary orbit can save on satellite
> >stationkeeping fuel and prolong the vehicles life.
> >
> I've noticed that earlier, but IF PAS 7 is going to geosynch, and was
> launched by an Ariane, and all Ariane's now launch from Kourou at 1 deg.
> latitude - why would they do a plane change ??

Kourou is at 7 deg, thus the satellite needs to do a plane change. 
The supersynchronous transfer orbit lowers the delta v required to 
inject into GEO from 1509m/s to 1473m/s. This results in a propellant 
saving of about 0.7% for the satellite. The disadvantage is that the 
third stage of the Ariane has to deliver an additional 220m/s to 
inject the satellite into supersynchronous transfer orbit, lowering 
the payload capability from about 4200kg to about 3950kg.

---
Jens Lerch
jlerch@geocities.com
Please visit my Astronautics Page at
http://www.geocities.com/CapeCanaveral/2221