SSTO Rocket to the Mun and back.

[Fredonia]

I know that making SSTO rockets is possible in this game because I've made a few after seeing that one guy that made the Pegasus Clipper inspired rockets.

What I'm wondering is if it's possible for a single Stage to Mun rocket... I haven't exactly worked out the delta-V requirements, but I know it's up there. I keep running into the problem of adding things and seeing my delta-V plummet. I can get an SSTO rocket that can return and have 1kms deltaV left upon Kerbin return, but can't get anything to the Mun and back...

Ideas? There's no real practical reason to this, it's more of a, "Because I can!" type thing.

[ThePsuedoMonkey]

It is quite possible: http://forum.kerbalspaceprogram.com/showthread.php/27805-SSTO-to-the-Mun-and-back

[Fredonia]

It is quite possible: http://forum.kerbalspaceprogram.com/showthread.php/27805-SSTO-to-the-Mun-and-back

Those are space planes, I 'm talking about SSTO rockets that take off from the launchpad, not the runway.

[rryy]

I built a rocket-only SSTO that has a lot of dead weight that makes it look aerodynamic. If I remove that, add some more fuel, and maybe replace the Mainsails with engine clusters, it may be able to get onto a flyby trajectory of the Mun.

Yes, that pile of fuel tanks can make it into orbit.

[ThePsuedoMonkey]

Sorry, misread that and was like "I did that!"

So round-trip to Mun from LKO needs 3420 dV which would be a mass ratio near 1.1 for an LVN, and the 4500 to get to LKO with an aerospike you'd need a mass ratio of 3.2. Multiplying those gives an overall mass ratio of a bit over 3.5, so it must be possible (going to try it now).

Edit: wrong ratio for LVN, should be 1.5, giving an overall around 5

Edited May 15, 2013 by ThePsuedoMonkey

[diegzumillo]

I've been trying to do that for a while now with no success. I just made a space plane capable of going to the mun and returning, but all my VTOL prototypes just barely reach orbit, let alone have enough fuel for a trip to the mun, landing and returning. I'm curious to know if anyone makes it, as I'm not a huge fan of planes either. docking with orbit stations is hell and achieving orbit is also more complicated.

[Uncle Mort]

I've just had a go and managed an "Apollo 8" style mission. Mun orbit and return.

I misjudged my return burn, used the remainder of my fuel, skipped through the atmosphere ended up with a semi-hard splashdown on parachutes only.

[Aphox]

I built a rocket-only SSTO that has a lot of dead weight that makes it look aerodynamic. If I remove that, add some more fuel, and maybe replace the Mainsails with engine clusters, it may be able to get onto a flyby trajectory of the Mun.

Yes, that pile of fuel tanks can make it into orbit.

That thing looks like farmer John inherited some weird stuff and though it would be cool to send his grain silos into space.

[Uncle Mort]

Success on the "Apollo 8" style mission.

Landed on empty though, so how to manage a landing on the Mun and safe return I've no idea.

[itsme86]

Wouldn't this technically be a SSTMAB rocket?

[katateochi]

I got a single seater SSTO to Mun orbit, but needed to refuel to get home again. I'm sure it is very possible.

Ideas? There's no real practical reason to this, it's more of a, "Because I can!" type thing.

Well thats a good enough reason, but I think there is a "practical" reason. I'd really like something that could SSTO (or SSTMAB!) as a means of doing crew transfers to Mun bases. So it would need to be able to take a number of Kerbals too. There is just something rather satisfying in the idea of being able to do a 'meaningful' mission, return to land at KSC, refuel and then set off again without having to load/reload another craft. High on my list of things to attempt.

[Van Disaster]

I'd really like something that could SSTO (or SSTMAB!) as a means of doing crew transfers to Mun bases. So it would need to be able to take a number of Kerbals too.

It'd be slightly more sensible to KOTMAB ( Kerbal orbit to Mun and back ... hey, these acronyms are fun ) from a station - the hard part is lifting from Kerbin, lugging all that SSTO weight to Mun and back is too much compromise for me. Bad enough doing a round-trip plane.

[Fredonia]

I've just had a go and managed an "Apollo 8" style mission. Mun orbit and return.

I misjudged my return burn, used the remainder of my fuel, skipped through the atmosphere ended up with a semi-hard splashdown on parachutes only.

I hadn't even thought of using intakes and jet engines...

[tavert]

Those are space planes, I 'm talking about SSTO rockets that take off from the launchpad, not the runway.

Totally doable, no jets required. http://imgur.com/a/uA4c5#0

Though if you want more crew capacity you'll have to either scale this up or use jets.

SRB's are great for takeoff (you can carry more liquid fuel for later without worrying as much about TWR at liftoff) and don't have much dry weight. I have 3 T30's in this design, with fuel lines routed so the outer 2 run out of fuel first, then the middle T30 runs out, and finish getting to orbit and do the whole Mun round trip on 2 LV-N's.

Edited May 16, 2013 by tavert

[dharak1]

I saw a SSTO that could escape KERBOL a while ago not sure what it was called though.

[tavert]

I saw a SSTO that could escape KERBOL a while ago not sure what it was called though.

There are a bunch of those here: http://forum.kerbalspaceprogram.com/showthread.php/26975-The-Single-stage-Altitude-Challenge (see pages 3, 6, 7)

The delta-V requirements for Mun landing and return are comparable to escaping Kerbol, but to escape Kerbol you don't need to worry about TWR or set the craft up for landing either on the Mun or back on Kerbin.

[R4_Unit]

Some great stuff in here! Tavert, do you have the ship file for that? I tried to duplicated it in .21, but I think I must've missed something (or there have been enough changes since this post was made) since I couldn't get the design above 5km. Basically, as soon as the solids ran out, there was insufficient thrust in the 3 T30s + 2 LV-Ns.

[buzz66boy]

I know it's kinda already been said, but SSTOs seem much better as planes. I've landed an ssto on minmus, brought it back, and also on Duna and laythe (and brought them back too!). Mind you - I did NOT refuel.

[tavert]

Some great stuff in here! Tavert, do you have the ship file for that? I tried to duplicated it in .21, but I think I must've missed something (or there have been enough changes since this post was made) since I couldn't get the design above 5km. Basically, as soon as the solids ran out, there was insufficient thrust in the 3 T30s + 2 LV-Ns.

Bit of a necro, but since you asked nicely, I'll see if I can dig up that craft file and post it for you. Don't think all that much has changed since I first made it, you can save some mass by using the 1-man lander can now (or a seat if you're so inclined). 3 T30's and 2 LV-N's should be enough to lift nearly 78 tons on Kerbin. With the SRB's empty my craft above should weigh something less than 67.7 tons, so maybe you were having problems with thrust being blocked by my odd mounting of the landing gear? Does the F3 menu indicate any part damage?

I know it's kinda already been said, but SSTOs seem much better as planes. I've landed an ssto on minmus, brought it back, and also on Duna and laythe (and brought them back too!). Mind you - I did NOT refuel.

Doesn't have to be a plane, but SSTO's are much easier using the jet engine due to its very high effective specific impulse. Rocket-only SSTO's are an interesting and fun challenge.

[Fredonia]

WOW! I almost forgot I posted this thread! haha I only ever got something to LKO without being able to bring it back in for a powered landing. I figured it'd need around 6km/s dV to make the trip. That sound about right?

[Tiron]

I've only done SSTO Spaceplanes, and gave up on landing on the Mun with it. It had enough fuel to GET there, but it'd always run out a bit above the ground and end up either scattered across the landscape or with SOME breakage. Also, landing a spaceplane on the Mun is Hard even without that: They're designed, generally, to land horizontally...which you can't really do on the Mun. So you either have to put landing legs on the back of it, or land on your nozzles and try to flop it onto the wheels. It's hard.

For a spaceplane it's much easier to go to Duna: Basically the same Delta-V to get there, you can aerobrake, and land horizontally.

For a rocket SSTO it's probably easier to go to the Mun. Duna's atmosphere is so thin parachutes don't cut it, and the Mun's lower gravity makes it easier to land without them.

[Van Disaster]

That was takeoff, but it shows both sets of engines...

Two sets of rockets, and control groups. Transition is a bit tricky but basically retroburn with the main engines until vertical, kill vertical velocity ( actually helps to be going up slightly ), engines off and flip horizontal. Swap active engine set, throttle up again.

[R4_Unit]

Bit of a necro, but since you asked nicely, I'll see if I can dig up that craft file and post it for you. Don't think all that much has changed since I first made it, you can save some mass by using the 1-man lander can now (or a seat if you're so inclined). 3 T30's and 2 LV-N's should be enough to lift nearly 78 tons on Kerbin. With the SRB's empty my craft above should weigh something less than 67.7 tons, so maybe you were having problems with thrust being blocked by my odd mounting of the landing gear? Does the F3 menu indicate any part damage?

Yeah, I knew it was a bit of a necro...but this design is inspiring to me! The gear were indeed the issue. I moved them to the sides of the solids and now all is well. I'll need to keep this in mind when I build more SSTO rockets in the future. In the past I've concentrated on designs using the T30 and the aerospike, with the odd LV-N, T45 or mainsail tossed in when higher isp, control, or thrust was needed. I never thought that solids have their place in SSTO designs!

[tavert]

Yeah, I knew it was a bit of a necro...but this design is inspiring to me! The gear were indeed the issue. I moved them to the sides of the solids and now all is well. I'll need to keep this in mind when I build more SSTO rockets in the future. In the past I've concentrated on designs using the T30 and the aerospike, with the odd LV-N, T45 or mainsail tossed in when higher isp, control, or thrust was needed. I never thought that solids have their place in SSTO designs!

In case you still want that craft file, here you go: https://dl.dropboxusercontent.com/u/8244638/SSTOMAB%207f%20stock.craft

I removed MechJeb in case you don't have it, go ahead and put it back on if you want. An electrical system would also be a good idea for 0.21 use, and bits like ladders for EVA. I totally forgot what ascent settings I had used for this before, but found a new set that worked, it still flies and has over 2800 m/s delta-V remaining once in orbit.

The solids are nice for an initial TWR boost, and they don't weigh much empty so it's not that bad to carry them around the rest of the trip. You can't refuel them, but ah well. I wonder if using a seat and maybe the new small inline engine could help bring the size of this design down...

Edited August 2, 2013 by tavert