SSTO's hate me, so I hated them back!

[Ozzallos]

...And went for a direct insertion hybrid

The StarScream Orbital Return Vehicle solves a few problems I've been having-- First, getting a single stage lander into orbit. I think the last time I was able to make that work was in .21 or earlier. Version tweaks have made it so that brute forcing your way through the atmosphere is hideously consumptive for F/O engines, forcing multiple stages or SSTOs as the most efficient path to orbit. This also presents a problem landing on other planets with atmosphere, some being more punishing than others in that regard. SSTOs are supposed to be the solution to both problems, except, well... They hate me. I can barely build them and can't land to save my life unless I load them up with parachutes. Sure, I can put them atop their own booster, but that kinda defeats the point, right?

So I said screw it and decided to put those jet engines to better use. The ultimate goal was to get a 3-man capsule into Kerbit orbit using a fully reusable, single stage vehicle. I knew from experience I could get a SSTO to around 21km before stalling the Turbojets out, and the Liquid Fuel consumption to that height is stupid efficient compared to anything else in the game. After some experimenting, RAPIERs became the engine of choice for this new project for the same reason they're good for space planes-- While they're not immensely powerful or fantastically efficient, you're not hauling dead weight up by switching between Turbojets and F/O engines. The efficiency to altitude would pay for itself.

The StarScream started life as a ten engine vehicle with roughly 3k of fuel (or rather 6k F/O total). Fueling balance quickly became an issue between atmospheric and space modes, and I would find myself with up to a 300-500 unit fuel disparity once all burns had been completed. Ultimately I would end up hauling around an excess of oxidizer as dead weight once the liquid fuel was gone. Capsule placement was also problematic. I'm never a huge fan of tower top configurations and the number of engines occupying the base made ladder access tricky. I might try a bottom load configuration for the capsule later, but for now we're keeping it simple. Engine switchover usually occurred around 19-20km in versions one through nine; not spectacular, but within expected perimeters.

Block 10 is where things really began to come together. Two RAPIERS were stripped away and liquid fuel added through eight Nacelles just to see if I could still achieve orbit on the reduced thrust, let alone take off with just over 3k of fuel. It turns out the answer was yes, amazingly enough. Liftoff and climb performance was hardly spectacular. In fact, it takes eight seconds at full throttle to even lift off while the engines spin up, and the climb through 10km is pretty lethargic compared to the ten engine array. At 15km is where the engines start to get some back and the Nacelles pay for themselves via air intake. When paired with another eight Radial intakes and the already present shock cones, the RAPIERs hung on to atmospheric mode for a full 23km! My last attempt stuck it out until 25km! By the time they switch over to F/O mode, the StarScream's velocity is pushing about 475m/s... Not supercharged by any means, but considering it only cost you about 700 units of fuel it's a goddamn bargain while F/O mode quickly makes up any velocity deficit. By the time you hit orbit, fuel and oxidizer are nearly balanced-- No dead weight.

Most of my insertions into orbit have about 500 units of F/O remaining, more than enough for maneuvering to a higher orbit and rendezvous for refueling. This was part of the intended purpose, after all-- Launch the ship as a stand alone vessel, refuel in orbit and potentially link up with a cruise stage so that it can parachute drop onto other planets and return to orbit, refuel and do it again. Block 10 also rearranged the engine placement so that it could be launched easily from atop a booster stage if one wanted to skip the refueling step. The only real drawback is that this particular all-in-one lander is only rated to Kerbin gravity atmospheric planets or less. Speaking of landings, they are accomplished by an eight parachute array. Even with them, a full fuel load will bring you in hotter than the struts will take, so be prepared for a last minute braking burn and remember those engines take time to spool in atmospheric mode. In the event of an inflight emergency, the command module can be jettisoned to land alone safely. Even so, you have to really try to screw up with this lander. It's very forgiving at the controls and doesn't get squirrelly like some SSTO designs.

I'm working on larger ORV's, but so far the results have been less than optimal due to the sheer number of engines involved. If you like this one, however, let me know and I'll post the file somewhere.

Edited March 29, 2015 by Ozzallos

[Columbia]

Mm.. Looks fashionable!

I wish you could offer some craft files, though..

[Tweety]

These are my favourite kind of SSTO's at the moment. The time spent building these and getting the first into orbit is far far less than designing SSTO space planes which although I love the SPH this is clearly the most efficient way to spend my limited KSP time nowadays.

Great design though, if you drop a DL link I will certainly get it just for the ladders!! I ALWAYS forget them.

Tweety