Stumbled upon SSTO Rocket design

[MajorThomas]

(I haven't found any SSTO rocket threads, apologies if I missed it.)

Last night while fooling around with using octagonal struts to add attachment points for rocket engines, I slapped together a simple rocket very quickly, and in the first test sent Jeb up to a ridiculous altitude of 890 km. I thought maybe something with this much capability could make it into orbit?

The second test showed that indeed, this rocket can. So I have apparently stumbled into an SSTO rocket design that can get into a 72 x 80 km orbit, and even have a bit of fuel (~ 1 %) leftover to deorbit.

Pic:

Parts list:

Mk 1 (small, one Kerbal) pod

Small parachute

Small decoupler

Small (not smallest) Rockomax, full-width fuel tank

Small Rockomax engines, 0.1 mass and 30 thrust each, x5

4 octagonal cubes (tiny), arranged with fourfold symmetry on the bottom of the fuel tank. Each takes one engine. The 5th engine goes in the center at the usual attachment point.

No antennas, batteries, panels, fins, legs, anything else.

[GluttonyReaper]

Yep, this is a thing. It works because those Rockomax engines are incredibly light.

[I_Killed_Jeb]

i believe you can even make it out of a smaller tank with one engine, i recall seeing one such design somewhere around here.

[MajorThomas]

Yep, this is a thing. It works because those Rockomax engines are incredibly light.

I had a feeling. Also the ISP is a respectable 360 s, I'm sure that helps.

i believe you can even make it out of a smaller tank with one engine, i recall seeing one such design somewhere around here.

Inspiring...let me try that, will post results here if I succeed.

Ah the joys of being laid off...got some time to do KSP.

[numerobis]

T30 with that tank also works, if you fly carefully.

[Caelib]

The only problem is that you have a decoupler in there, which makes it a two-stage craft. SSTO typically refers to a craft that is completely reusable -- the biggest cost of launching spacecraft isn't from fuel, it's from the loss of hardware.

[MajorThomas]

The only problem is that you have a decoupler in there, which makes it a two-stage craft. SSTO typically refers to a craft that is completely reusable -- the biggest cost of launching spacecraft isn't from fuel, it's from the loss of hardware.

Very good point. With the decoupler removed and some legs added...if the weight isn't more, and the drag less...I might be able to do a true SSTO.

[I_Killed_Jeb]

Ah the joys of being laid off...got some time to do KSP.

vibes friend. hope you find a job soon. or not, since ksp is the activity that should be full time for any rational human

[Caelib]

Very good point. With the decoupler removed and some legs added...if the weight isn't more, and the drag less...I might be able to do a true SSTO.

Yeah, that might do the trick -- based on past experience, the extra weight from the tank, landing legs and engines might require you to add some radial parachutes to the tank ... without it, you're going to be cruising in at greater than 10m/s, which means explosive results upon landing

[Padishar]

I've just been running a few tests on this and I've added a FLT-200 and 100 to the stack, three landing legs and a single chute on the capsule (plus a bit of strutting to be safe) and given it 7 engines in total. KER says it has about 4850m/s and it gets to a 72km orbit with about 350m/s left so that sounds about right. On re-entry, you keep a little fuel (about 50m/s worth to be safe) and disable 3 of the engines to reduce the TWR to manageable levels. Then pop the chute at about 1000m altitude and then wait. Once the chute fully opens it will slow to approx. 11.5m/s and you can use a little burst of throttle just before touchdown to get it low enough to not go bang...

The 350m/s was enough to set up a rendezvous with my station at 200km but it didn't then have enough left to deorbit and brake-burn and had no way of docking so I'm redesigning it for less weight, a docking port, remote control and radial chutes so it can be used as a station taxi. Craft and pics soon...

[MajorThomas]

Soft landing achieved, with about 1% fuel remaining!

[Vanamonde]

I suspect you didn't find any such threads because you weren't looking in the craft exchange sub-forum, which is where this belongs, and to which it has now been moved.