Challenge Expert/Realistic XR2 to the moon and back in 48 hours

[DylanShepton]

I'm new to Orbiter and don't know very much about spaceflight, but is it possible to do a slingshot off the Moon to get a higher velocity on the return back to Earth and use aerobraking (without any fuel) to slow the XR 2 down?

If possible, could you use TransX to plan the trajectory and IMFD to plan the slingshot?

 

[hribek]

Yes, absolutely. I'm not sure exactly how fast you can get back using a free-return trajectory. Definitely something around 2-3 days one way but that's just a rough estimate.

By the way, one of the playbacks that come with IMFD contains just that.

 

[C3PO]

Yes, absolutely. I'm not sure exactly how fast you can get back using a free-return trajectory. Definitely something around 2-3 days one way but that's just a rough estimate.

By the way, one of the playbacks that come with IMFD contains just that.

Hyperbolic free return? Never heard that one B4

 

[DylanShepton]

Hyperbolic free return? Never heard that one B4

:lol: I thought that the free return would be parabolic since IMFD's Course program shows an ellipsoid path from Earth to the Moon and back.

 

[hribek]

So is it an ellipse, an ellipsoid (xD), parabolic or hyperbolic?

It won't be perfect, and it depends on what you take as reference. I think the trajectory should be a hyperbola from Moon's point of view. Taking Earth as reference, it will be an ellipse. If we are talking about such a gravity assist that brings you back to Earth with roughly the same Earth PeA as you left with.