# Calculating hyperbolic orbit elements for interplanetary intercepts

As part of a final year project at university I'm currently trying to simulate an interplanetary transfer between Earth and Mars for a manned mission. The ultimate aim is to use NASA's GMAT to simulate the mission and calculate the detailed orbital elements at each point of the mission as well as $\Delta v$ requirements etc...

We've narrowed down our departure window to 26 Jun 2035, taken from the Trajectory Browser webpage, also by NASA. The issue I've now come across is that to simulate the orbit within GMAT we need a lot more detail than the Trajectory Browser provides.

Other than GMAT, is there any software which I can input my current parameters (departure date, parking orbit, transfer time, dV) and get out the hyperbolic elements of that transfer? For simulation in GMAT I need either SMA/RAAN/INC/ECC/AOP/TA or $\Delta v$ in VNB components. If not, is it possible to calculate them by hand?

I have asked a similar question on the GMAT forum, but that seems to have died a bit of a death recently.

• That sounds very interesting, are the results going to be published somewhere? – mike Apr 24 '17 at 13:39

Concerning your specific project though, if I may, I would recommend doing an initial analysis using a tool like mine to find the cheapest $\Delta v$ trajectory from Earth to Mars, and then plugging in the returned values as $C_3$, right ascension and declination of launch into GMAT, and using GMAT to iterate and optimize these values. Also note that you don't need the delta-V expressed in the VNC frame: the C3, DLA and RLA values are enough if you assume that you spacecraft will be sent on an interplanetary trajectory by the launch vehicle.