Re: Using TLEs to reverse time

Sat, 9 Nov 1996 04:51:02 -0500 (EST)

On Fri, 8 Nov 1996, Huston, Stu wrote:
> I need to be able to determine the position of a spacecraft (in this case, 

Position in the sky or over the earth?  If the latter, MrOrbit does the 
job nicely.

> position.  Now suppose I have 2 elsets, with elset #2 at a later time than 
> elset #1.  Also suppose that the time I need the spacecraft position is 
> closer to #2 than #1.  Is it valid to use elset #2 to determine the 
> position?

Yes, that's fine.

>  Assuming no maneuvers occurred between the time I'm trying to 
> simulate and the epoch of elset #2, those orbital elements should be more 
> representative than those of elset #1.  But, is there something inherent in 
> the SGP routines that requires the epoch of the elset to be earlier than the 
> epoch of the satellite?

No, I don't think there should be a problem.
> I hope this is a legitimate request for this list - it may help someone 

Sure it is!

Jay Respler
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