Is it Possible?

[Voyager55]

Is it possible to build an SSTO capable of multiple landings and ascents to orbit on a Kerbin/Laythe like body, like interstellar's Ranger craft? I'm working on a exploration craft assembly and if it's possible to do what I've asked I'd love to see your guy's crafts and ideas. I'm also trying to keep it relatively compact.

[zekes]

You'd need REALLY Efficient engines, and have most of the craft be built out of fuel. And it would have to be BIG.

[numerobis]

Building a single-stage craft that gets from Kerbin to Laythe and back is a bit of a challenge, but it's definitely doable. Multiple landings and takeoffs from Kerbin is rather easier than that. Multiple landings and takeoffs from Laythe is pretty easy, if you have a nice landing area (the landing is the hardest part).

[Bill Phil]

If you had a Gas Core Reactor, easy. But without one.... Good luck.

Maybe with LV-Ns for the final boost, capable of SSTO on all bodies except Tylo ( can orbit with solid boosters, and not Eve or Jool, either), and in flight refueling of the ship ( really smart idea...) it could be done.

[Voyager55]

The SSTO itself only serves the purpose of an orbital shuttle for my Laythe base, my Endurance analog will do the transfer burn and orbital insertion. So i'm really just trying to make the smallest and most efficient possible SSTO that can hopefully make more than one landing and ascent before refueling.

[SkyRender]

Shouldn't be too hard to come up with something for Laythe, particularly if you have Ferram Aerospace Research installed. Even with stock engines, a combination of turbojets and an LV-N should do it and give you a reliable enough multi-trip Laythe-worthy craft. Really it comes down to your technique and piloting skill in that case. Of course, a lot does depend on how many Kerbals you're trying to move back and forth. 1 to 5, no big deal. More than 5, you're gonna need a bigger spaceplane.

[Voyager55]

Shouldn't be too hard to come up with something for Laythe, particularly if you have Ferram Aerospace Research installed. Even with stock engines, a combination of turbojets and an LV-N should do it and give you a reliable enough multi-trip Laythe-worthy craft. Really it comes down to your technique and piloting skill in that case. Of course, a lot does depend on how many Kerbals you're trying to move back and forth. 1 to 5, no big deal. More than 5, you're gonna need a bigger spaceplane.

5 Kerbals is the max I would need to transport, I'm trying to engineer it as a VTOL because regular landings on Laythe are extremely difficult for me. VTOL's tend to be a bit more fuel hungry from my experience, unless i'm just bad at designing them.

[dryer_lint]

Considering that the Rangers apparently had super-efficient jet engines and ion/plasma thrusters, this would probably be tricky... they didn't actually have to do interplanetary transfers, though, did they?

[Voyager55]

Considering that the Rangers apparently had super-efficient jet engines and ion/plasma thrusters, this would probably be tricky... they didn't actually have to do interplanetary transfers, though, did they?

Correct, the Rangers were always carried by the Endurance during transfers.

Edited December 1, 2014 by Voyager55

[Monkeh]

Not exactly a single stage but a single launch to Laythe and back was accomplished by my little intrepid dudes. Barely. I documented it here. It was one helluva mission!

More recently I went back for science and with a rover.

Got to aerobrake around Jool.

And again at Laythe.

Still got 7000 delta v to get home

Then she drove to the beach, losing her helmet on the way. Oxygen confirmed on Laythe!

Spent the night under the bioluminescent clouds.

Is 3,300 enough to get home?

just about!

Nice one 'Bill!'

[Bill Phil]

Correct, the Rangers were always carried by the Endurance during transfers.

What about the Lazarus Missions, they said one Ranger per astronaut... Although they could have used a transfer stage.

[GoSlash27]

Absolutely.

I have a fuel hauler SSTO spaceplane that could do 2 trips on Kerbin If I burned the fuel it's delivering. With some mods, it could bring a few Kerbals as well.

It's not that big, either. About 13 tonnes.

If you want, I'm positive I can build you one.

*edit* It's not VTOL, though.

I have a design that could *maybe* do 2 trips VTOL, but that's a bigger job.

Best,

-Slashy

Edited December 1, 2014 by GoSlash27

[SkyRender]

So I got to thinking about your problem, and designed this:

It was built with a FAR-enabled install, so it would need beefier fuel tanks for stock, but the basic concept is solid. Basically, you take off vertically with the jet engines on the wing, then enable the horizontal turbojets once you're high enough, and when you've gained enough altitude that the basic jet engines are about to flame out, you shut them off. Other than that, it behaves exactly like any other spaceplane. The various values for winglets, fuel levels, etc. are not optimized on my own build of this thing, but I can tell from my test flight that once it is optimized, it can easily do 2 round trips to Laythe's surface on one pair of 360/440 tanks. (NEVER put fuel in that rear tank, or the whole thing gets horribly unbalanced!)

Edited December 1, 2014 by SkyRender

[merendel]

If you have the KSPInterstelar mod it would be rather easy. Between the fusion reactors and the thermal hybrid turbojets you can go prety much anywhere. Even after an ISP cap that was implemented with the most recent version those things in rocket mode have better ISP than anything in stock asside from an ion. They also work in airbreathing mode in any atmosphere as they are just sucking in atmosphere and heating it up for reaction mass instead of needing the O2 like stock turbojets. could probably make one that could do a couple landing/orbit trips on any body before needing to refuel depending on your payload to fuel ratio.

[Voyager55]

Thank you guys for all the input, and great ship design SkyRender, don't mind me using it? Or a slightly modified version?

[SkyRender]

Thank you guys for all the input, and great ship design SkyRender, don't mind me using it? Or a slightly modified version?

Help yourself! I believe in sharing my designs freely. Just a few notes when rebuilding it from screenshot:

1. The jet engines on the wings need to be as close to the center of mass as possible.

2. The rear fuel tank needs to always be empty of fuel (as I said before).

3. You'll need to adjust the side tanks' positions so that fuel drain on them does not change center of mass.

4. You'd be smart to set up action groups for toggling the 3 types of engines independently of one another, as well as the intakes.

5. As with any spaceplane, center of lift needs to be behind center of mass at least slightly.

[quasarrgames]

also, it seemed from the movie like the rangers only ever did one landing-orbit run. never multiple. they probably got refueled on the endurance after every flight.

[GoSlash27]

SX Double-Dipper craft file

This SSTO spaceplane will conduct 2 full round trips to LKO with inclination correction, intercept, rendezvous, and docking. It can then de-orbit, cruise to KSC, and land under it's own power both times. Carries 2 flight crew + 4 passengers. All stock parts and installation.

Action groups:

1) Toggle intakes

2) toggle docking collar, docking lights, and solar panels

3) deactivate rockets

Takeoff:

Maintain 100 m/sec airspeed to 40* pitch

At 10 KM altitude, pitch down to 30*

at 15 KM altitude, pitch down to 20*

Pitch as necessary to maintain 100 m/sec climb rate, but do not exceed 22* pitch

At flameout, throttle down until restart.

Maintain flameout/ throttle down/ restart until airspeed is no longer increasing Should be about 2,300 m/sec

Stage to engage rockets and hit action group 1 to engage rockets.

Reentry:

After retro burn, open intakes (action group 1), Retract solar panels, close docking bay doors, and turn off docking lights (action group 2) and disable rockets (action group 3)

After reentry heating subsides, throttle to 1/3 for cruise.

There's plenty of fuel to cruise back to base.

After landing, reset your staging, reactivate the rockets, and lather/ rinse/ repeat.

Best,

-Slashy

Edited December 1, 2014 by GoSlash27

[SkyRender]

So, I decided to see if I could improve upon my design.

As it transpires, I can! I've even provided the .craft this time. This one is properly FAR-balanced, and flies pretty much like a dream. It's a little shaky on the way up and down, but very controllable just the same. And I managed to rebalance it so the rear fuel tank can hold fuel, so it has an even more comfortable margin. Don't let the fuel levels in the screenshot fool you, that was before I finished fuel balancing and was also from a decidedly less-than-ideal ascent. Also, it was not to Laythe orbit but rather to Kerbin orbit, which takes around 33% more fuel than Laythe anyway. I've left detailed instructions on its use in the description, and would like to add that putting the brakes on during lift-off is generally a good idea.

Edited December 1, 2014 by SkyRender

[cantab]

It's no surprise that it's possible. Thanks to a bug the jet engines have extremely high Isp, they're actually several times as efficient as the ions, and if you want you can get pretty close to orbital velocity.

The designs shown have been planes, but an alternative general approach is a jet rocket, using pure thrust without relying on aerodynamic lift. That might be suited to recreating the cargo landers.

[magnemoe]

Now, another issue is if an SSTO to laythe is practical, it might be more practical to do two launches and fuel up in LKO.

single stage Laythe and return is more for bragging points.

As for SSTO I uses tail sitters, benefit is less engines and no balancing issues. I use two orange radials in front to push nose up then speed is low then use parachutes to stabilize.

Main downside is that you need TWR higher than 1 on initial takeoff.

[Sli 41]

So I got to thinking about your problem, and designed this:

http://www.skyrender.net/lp2/ksp/laythe_vtol.jpg

It was built with a FAR-enabled install, so it would need beefier fuel tanks for stock, but the basic concept is solid. Basically, you take off vertically with the jet engines on the wing, then enable the horizontal turbojets once you're high enough, and when you've gained enough altitude that the basic jet engines are about to flame out, you shut them off. Other than that, it behaves exactly like any other spaceplane. The various values for winglets, fuel levels, etc. are not optimized on my own build of this thing, but I can tell from my test flight that once it is optimized, it can easily do 2 round trips to Laythe's surface on one pair of 360/440 tanks. (NEVER put fuel in that rear tank, or the whole thing gets horribly unbalanced!)

Would it be possible to do something like that but with rocket engines instead so it could land and take off from anywhere? I was thinking a sort of multi purpose craft like that would be pretty cool and I tried to build something but it's just impossible to keep it balanced and it fails horribly when I try to take off. Maybe I'm messing up the fuel tanks placement, but yeah the idea would be to be able to land and take off like a VTOL and then rendezvous with a bigger vehicle in orbit to refuel and go to the next planet.

[SkyRender]

Would it be possible to do something like that but with rocket engines instead so it could land and take off from anywhere? I was thinking a sort of multi purpose craft like that would be pretty cool and I tried to build something but it's just impossible to keep it balanced and it fails horribly when I try to take off. Maybe I'm messing up the fuel tanks placement, but yeah the idea would be to be able to land and take off like a VTOL and then rendezvous with a bigger vehicle in orbit to refuel and go to the next planet.

Sure, should be doable. Just replace the basic jet engines with sufficiently powerful rocket engines (probably aerospikes). But the fuel efficiency would drop through the floor that way. Better just to build fat landers that are designed for specific bodies instead of making a jack-of-all-trades lander that's good at none of them.

[Frank_G]

Doing that in stock KSP on Kerbin will be a real challenge. On Laythe it will be easier for sure. Nice challenge though, as i am currently launching my first Laythe colony missions. And a spaceplane Still needs to be designed.

I would like a design that can transfer some kerbals or deliver a ton of cargo by using a modular system. I love the ideas pointed out by cantab. I will try some designs this week.

[GoSlash27]

http://wikisend.com/download/876322/Kerbilander.craft

This is a VTOL double SSTO for Kerbin. The trick is sticking the landing due to the turbine lag of the jet engine.

If you can stick the landing, it'll do 2 full SSTO missions without refuelling. Ascent is just a matter of maintaining 100M/sec climb rate, throttling as necessary to keep the jet lit. Then switch to rockets and perform a radial burn at target altitude to circularize.

O2 reserves are adequate to do 2 each of circularization burn, inclination correction, intercept, rendezvous, and deorbit. Monopropellant is adequate to do 2 full orbital dockings. Fuel is adequate to do 2 SSTO launches, 2 landings, and 2 of all orbital maneuvers.

If it were up to me, I'd go with the spaceplane design. Not only better mass ratio and efficiency, but it is much easier and safer to land exactly where you want to be.

Best,

-Slashy

Edited December 2, 2014 by GoSlash27