Baby Buran

[sevenperforce]

After a rousing discussion of side-slung launch vehicle balancing at the following thread...

...I built a full-size Energia-Buran stack and started experimenting with Mun missions.

However, the complexities of balancing thrust (even if it's a touch easier than an STS-style shuttle) made me think...just how small an Energia-Buran clone could I manage to make?

Meet...the Baby Buran.

At a scant 10.3 tonnes, it's hard to imagine anything much smaller. But it does what it's designed to do!

No room for solar panels and no mass budget for an RTG, so it's all-battery-powered, with a probe core to allow it to do unmanned missions just like its much, much bigger brother. By default, the battery packs on the orbiter are locked so that only the one on the core booster is drained during ascent. It boasts a tiny heat shield on the underside, just in the right place to protect the cockpit, which also allows it to have a lightweight radial decoupler.

"Lemwig" sounded like a vaguely Russian name, I thought!

Just like the real Energia-Buran, the core has four engines and each of the Zenit-clone strap-on boosters has 4 locked nozzles and four gimbaling control nozzles. Of course, here they are all the same size, but no one is looking THAT closely.

Liftoff!

Two of the Oscar-Bs on each side booster are drained to allow a liftoff TWR>1.

And Lemwig careens off toward the heavens.

The engines are angled to provide roughly consistent thrust as the fuel tanks drain, but it's still a bit of a fight. There is a planned roll-over about halfway through ascent, both to take the pilot out of the airstream and to help maintain a good heading.

Glamour shot!

Here comes the roll-over.

Approaching booster burnout. By this point, I've already used an action group to cut two of the four booster engines to maintain thrust symmetry.

Boosters jettison together, just like Energia-Buran. They do not, however, separate and land independently on chutes, landing legs, and retrothrusters. I am not a god.

Good trajectory at separation.

Throttling down to reduce asymmetric torque below what my reaction wheel can handle.

Booster burnout! Turning my battery pack back on and preparing for booster separation.

Good separation. My two linear thrusters kick on to push me into orbit.

The burn shouldn't actually be too terribly long.

Ignore the maneuver node; the apoapse is way higher than I'll actually be going to. Just wanted a good maneuver vector.

Isn't it cute?

And we've got a good orbit!

Granted, that's not a LOT of dV for stuff to do in space, but with a good intercept you could rendezvous with a space station. Or it could be sent up unmanned to rescue a stranded Kerbal, thanks to that probe core.

Anyway, with no further ado, here's the deorbit burn!

I ended up quickloading because my first attempt didn't get me anywhere near the KSC, and for some reason my landing gear glitched into an odd position. Oh well; can't be helped!

Coming in hot, but it's nothing this kool Kerbal can't handle.

Honestly was more worried about that landing gear.

Hey, lookee there! We just might make it!

Nosing forward to get a better glide ratio.

Trying to turn...my inclination was a bit off.

Burning off remaining monoprop to extend my range and lighten my load. Besides, who wants that nasty hydrazine still in the tanks with an open-cockpit deadstick landing?

Looks like a good descent.

Lining up for landing.

Last-moment corrections.

Will I make it?

Why, I do believe I will.

Here we go! Let's hope that wonky landing gear holds up.

Touchdown!

And, done.

He's happy to be back!

 

 

 

[Geonovast]

This is awesome!  Any chance you can share the craft file?

[sevenperforce]

7 minutes ago, Geonovast said:

This is awesome!  Any chance you can share the craft file?

Thanks! And sure, here you go!

https://files.fm/u/9pxnwgpb#_

[Jack5.exe]

How about a payload version?

[sevenperforce]

6 minutes ago, Jack5.exe said:

How about a payload version?

Recoverable or no? If you don't need it to be recoverable (e.g., Energia-Polyus), just make the booster stack into a subassembly and replace the orbiter with your encapsulated payload.

If you need it to be recoverable...well, what payload exactly do you intend to fit in that small of a space?

[Jack5.exe]

Just now, sevenperforce said:

Recoverable or no? If you don't need it to be recoverable (e.g., Energia-Polyus), just make the booster stack into a subassembly and replace the orbiter with your encapsulated payload.

If you need it to be recoverable...well, what payload exactly do you intend to fit in that small of a space?

starter payload... the second smalled octagonal grey control thgy and an antenna on it

[Geonovast]

I would consider the Kerbal to be the Payload.  Stuff like this would be good for Space Station crew rotation.

[sevenperforce]

3 minutes ago, Geonovast said:

I would consider the Kerbal to be the Payload.  Stuff like this would be good for Space Station crew rotation.

Indeed. Of course, I can build a small recoverable SSTO to do the same job, but this is still pretty darn small.

12 minutes ago, Jack5.exe said:

starter payload... the second smalled octagonal grey control thgy and an antenna on it

Here's what I suppose you might do if you wanted a payload version.

The heat shield and command seat are removed and the front cone has been attached to the rear node of the orbiter, then rotated and translated up. The whole profile has been elongated slightly to fit the payload. Should handle roughly the same on ascent and re-entry, though without batteries or solar power that starter payload isn't going to be transmitting for long.

[NotAgain]

Welp. That was impressive.

[roboslacker]

It's so cute.