Interplanetary SSTO - possible in 1.0.4?

[yorshee]

I've been trying to make an SSTO that goes to Duna and back. I've succeeded in landing it on Duna, and my best attempt has around 2800m/s of dv when landed on Duna. I can get it into orbit around Duna again, but barely. It has around 400m/s left when in Duna orbit, which isn't enough to return - even Ike slingshots aren't enough to get me back to Kerbin.

I managed to make an SSTO capable of returning to Kerbin but it uses drills and an ISRU converter to refuel so it feels sort of cheat-y to do that, so I want to make a craft that doesn't do that.

My question is - is it possible to make an SSTO capable of landing on Duna and then returning to Kerbin without refueling?

[Wanderfound]

I've been trying to make an SSTO that goes to Duna and back. I've succeeded in landing it on Duna, and my best attempt has around 2800m/s of dv when landed on Duna. I can get it into orbit around Duna again, but barely. It has around 400m/s left when in Duna orbit, which isn't enough to return - even Ike slingshots aren't enough to get me back to Kerbin.

I managed to make an SSTO capable of returning to Kerbin but it uses drills and an ISRU converter to refuel so it feels sort of cheat-y to do that, so I want to make a craft that doesn't do that.

My question is - is it possible to make an SSTO capable of landing on Duna and then returning to Kerbin without refueling?

Probably; Duna transfer is about 1km/s, aerocapture and landing is free, return to orbit is something like 1.5km/s. It's not that much more than a Mun trip.

What you want is just enough RAPIERs to get off the runway and up to speed, just enough oxidiser to lift the apoapsis out of the atmosphere, a nuke or two plus as much LF as you can carry. For example, this one (built for FAR, but it'll do as a demonstrator):

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3,741m/s ÃŽâ€V in LKO unrefuelled.

It's a lot easier to do if you're willing to top up the tanks in LKO, though; 5,000m/s or better is available of you do that.

The tricky bit with Duna is the landing, not the flying. Airbrakes, chutes, retrothrusters and wide-set landing gear are all recommended.

[yorshee]

I can land on Duna with no airbrakes if I land on a flat area (oh the amount if times I've smashed into the side of a hill...) though airbrakes do sound like a good idea as I find myself using my engine to maintain a steady glide until I've bled off enough speed to land, which is wasted fuel.

My issue isn't really landing though, I can do that ok, it's getting back to Kerbin that's the hard part. Because of Duna's thin atmosphere and my awful TWR I'm spending a lot of time in Duna's lower atmosphere because I can't pitch up a lot without losing speed. Because I'm spending so much time in the lower atmo, I'm wasting dv from pushing through the atmosphere, but I can't not do that because I lose speed otherwise.

I think my issue is the TWR problem, I need to save some oxidiser for my closed-cycle RAPIERs to use at Duna.

EDIT: Should I post my craft here too? o:

Edited June 27, 2015 by yorshee

[Red Iron Crown]

I'll just leave this here:

Pretty sure if I replaced the center LF tank with an LFO tank it would be Duna return capable without refueling. TWR would be pretty marginal for Duna ascent on the LV-N alone.