# NASA GMAT sample script providing deltaV above analytical result when aiming to GEO Height

I am using the GMAT example script available at \samples\Ex_GEOTransfer.script (R2022a) to compute de deltaV from LEO to GEO including change plane maneuver.

The problem is that the script seems to be aiming for a supersynch RMAG of 85000km:

Achieve 'Achieve RMAG' DC(geoSat.RMAG = 85000, {Tolerance = .1});

But when I try to use this example to compute a simple LEO to GEO aiming directly to 42164 the scripts returns a total deltaV above 5km/s.

For example LEO_height=500km, LE=_ecc=0, LEO_inc=45 to GEO > 5.1km/s, 10% above the expected value from analytical formulae.

Did anyone experienced the same issue and could you provide a workarround? Thanks in advance!

• I'm not a GMAT user though it might help to provide a bit more context of what simulation you have tried. e.g. is this a) a "dead reckoning" approach where you specify the burn start-stop times, thrust, mass etc and the program just tells you the outcome of that one propagation, or b) is this script providing boundaries for an optimisation problem so there is more scope for surprises (sounds plausible given the quote from the script)? Commented Mar 18 at 20:16
• Superficially, for a 45deg starting inclination wouldn't be surprising that an optimisation (or even just a simple rulebase) would lead you towards a super-synchronous solution, though that doesn't illuminate why its different from your expected figure. Can you try some simple dead-reckooning cases to gain confidence in that part at least? Commented Mar 18 at 20:18