Recreating Luna 16

[Sid]

Luna 16, if you didn't know, was a Soviet moon landing probe which drilled into the surface and returned samples to Earth.

I want to give it a go in KSP ( without the drilling, obviously )

I've built the probe but I have no idea how to calculate the trajectory of the ascent vehicle. Due to fuel ( and realism ) considerations it will have to launch direct from the surface of the Mun to Kerbin without going into orbit first.

Any of you rocket scientists got any bright ideas ?

Edited July 19, 2013 by Sid

[IllicitMedic]

MechJeb...

[Sid]

Mechjebs 'return from a moon' will do that ? I'd sort of assumed - for no good reason -the probe would need to be in orbit...

[stupid_chris]

It needs to be in orbit indeed. Basically you'll want to shoot straight at the Mun's retrograde vector. If you launch in a straight line, you basically need the delta V to reach the Mun's escape velocity, and then to reenter Kerbin.

[capi3101]

Hmm. Okay, this is a shot in the dark, but WTH...quicksave first if you want to try this.

I'd suggest waiting until your surface position is about midway along the dark side of Mun.

Thrust retrograde - 270 at 45 degrees. Escape velocity for Mun is 807.08 m/s.

That should put you in a Kerbin orbit. From there's it's the standard fare...lower your periapsis into the atmosphere for aerobreaking.

Total delta-V for a Mun launch and return to Kerbin without return to Munar orbit is 1,500 m/s; if the probe's got at least that much, it should make it back no problem.

[Sid]

Aaah thanks guys, I'll have to check the ascent stage delta-V

Just tried a test flight in Kerbin orbit and discovered that Chief Designer Of Glorious Soviet Socialist Kerbal Space Program ( i.e. me ) forgot to give the re-entry vehicle a parachute. I suppose I'll have to send myself to Siberia for that

[Johnno]

Chief Designer Of Glorious Soviet Socialist Kerbal Space Program ( i.e. me ) forgot to give the re-entry vehicle a parachute.

In other news...

[Sid]

I love those cartoons Johnno

It's probably sheer luck, but my ascent stage returned to Kerbin just by burning straight up, and with much less delta-V expended than 1500 m/s

I'm confused now...or rather MORE confused...

Sadly the Mun samples were lost when the parachute failed to open. This was because Hero Of The Revolution Chief Designer left the RTG behind on the bit that stays on the Mun instead of putting it on the bit that goes back to Kerbin.

[capi3101]

sadly the mun samples were lost when the parachute failed to open. This was because hero of the revolution chief designer left the rtg behind on the bit that stays on the mun instead of putting it on the bit that goes back to kerbin.

d'ooooh!!!!!

[catmando]

sounds like a quality control problem in the workers paradise, comrade..

[Sid]

I think I'll call this answered seeing as you are all laughing at me now - that's a good thing though