is an Eve SSTO rocket possible?

[Kergarin]

3 minutes ago, Sharpy said:

 

Or wheels.

And then drive to higher place, or what is your plan? 

[Sharpy]

Yes.

Of course having the SSTO with wheels, and enough of them, and durable enough, and stable enough to climb the slopes, that's a challenge by itself.

I'm still thinking of infrastructure-based approach. Fully reusable stuff deployed to the surface that helps the SSTO back into the orbit. Like a really, really big truck. Maybe even boat-truck, as loading should be easier in case the SSTO splashes down.

[GoSlash27]

37 minutes ago, KerikBalm said:

but you could refuel at sea level, then relocate to the mountain, then refuel again...

"It's his project, so he'd be the one to ask. " - but you're the only one who said anything about sea level, unless he's edited it out since you read it/

1)  Yeah, you could.

2) It has wings, which are disadvantageous for a mountaintop SSTO. It's sitting at a typical low terrain height. It's refueling. Not hard to connect the dots. Nevertheless, I *asked* if that's what he's doing rather than stating it as fact, and if that's not his intention, I'm sure he'll let us know.

Best,
-Slashy

 

[Kergarin]

I could land at sealevel and then jump to my launchsite to refuel and get back, but I think both does not count as sea level return 

A ground based isru truck would save you from having isru on the ssto. But a boat will force you to launch from sea level.

Maybe an isru tanker plane would be an idea? That could easily reach ever landing site without the problems that wheels do have no eve.

Edited August 26, 2016 by Kergarin

[KerikBalm]

planes on eve at low level don't work well. In theory L/D is L/D even if the air is 5 atm or 1 atm - as long as mach numbers don't come into play.

Also while you need more lift because of higher gravity, that higher gravity means more potential energy for every meter of altitude... so glide ratio should be more or less the same... rocket powered planes have terrible Isp especially on eve, and it takes much more fuel to climb in altitude. Even on Kerbin (or earth for that matter) past a certain distance, ballistic trajectories are more efficient. I just like wings for a greater ability to "steer" towards the intended landing site. Of course a ballistic ascent and winged reentry can get better results... like the winged V2.

Anyway, to fly around in the low atmosphere requires very slow glides because of the atmosphere, and you'll want to get up higher because of that... so traversing eve for me seems to be a matter of going ballistic.

I've made some electric or LFO burning atmospheric engines that make eve planes ok... but so far none of the stats I've given them really enable SSTOing... at least not from sea leve, so I guess they're balanced. (I did have one set of stats for an air augmented rocket that was borderline for SSTO capability... its ram/mach augmented thrust was too high IMO, it got some really really good TWR).

I wonder how this challenge will change if we ever get stock electric atmopsheric propulsion... or some atmospheric turborocket/air augmented rocket propulsions...

[Sharpy]

25 minutes ago, Kergarin said:

 But a boat will force you to launch from sea level.

Boat-truck. Amphibian vehicle So that it picks the SSTO from the ocean and drives it to the mountain top.

 

...what progress was made with electric propulsion boats since 1.0.3? I heard buoyancy and water drag was overhauled. Of course jet boats are out of question, and rocket boats really miss the purpose...

[KerikBalm]

I haven't had any success with stock boats with "electric" propulsion outside of a big paddlewheel like design that just rolls along the surface of the water.

I tried to make one with propellor blades , withthe whole thing spinning like a propellor, but I couldn't get it to work.

[Kergarin]

23 minutes ago, Sharpy said:

Boat-truck. Amphibian vehicle So that it picks the SSTO from the ocean and drives it to the mountain top.

Ok, would like to see that 

 

I think a balloon or electric helicopter would be good on eve 

Edited August 26, 2016 by Kergarin

[Kergarin]

Hm... Helicopter.... 

[SingABrightSong]

Well then, it appears that you have won Kerbal Space Program. I hate to be "that guy", but is there any chance you'd be willing to share your .craft file? Or are you holding off until you've fully refined the design?

[foamyesque]

It's not sea-level SSTO -- not unless you count refuelling hops towards the mountain tops (I don't), and even then the ore concentration next to the oceans on Eve is 0%, so that won't work anyway. But I'm checking on the entry and refuelling process there, not the flight out, which I can do without needing to land on a tiny postage stamp of land.

The wings allow me to do a 0-fuel landing -- control accomplished entirely through aero surfaces -- and get away with a <1 TWR on liftoff, which saves me a bunch of engine weight. Right now I'm fighting with the landing gear on Eve takeoff; I want to save weight by making them as minimal as possible, but the combination of field takeoff, Eve's gravity, and the physics transition coming off of rails fully fueled are giving me some hassles. I've got 5.15km/s of vacuum deltaV and am carrying a 2.5m ISRU, two fullsized drills, 3 fuel-cell arrays, and 2 large fixed radiators, which gives me an efficient, closed-cycle ISRU unit. Careful fuel-flow design keeps my CoM shift during flight minimized.

The hopeful end goal is a ship which can land on Eve, get to orbit, and then repeat it indefinitely, without the support of a mothership of any description.

[Kergarin]

54 minutes ago, foamyesque said:

It's not sea-level SSTO -- not unless you count refuelling hops towards the mountain tops (I don't), and even then the ore concentration next to the oceans on Eve is 0%, so that won't work anyway. But I'm checking on the entry and refuelling process there, not the flight out, which I can do without needing to land on a tiny postage stamp of land.

The wings allow me to do a 0-fuel landing -- control accomplished entirely through aero surfaces -- and get away with a <1 TWR on liftoff, which saves me a bunch of engine weight. Right now I'm fighting with the landing gear on Eve takeoff; I want to save weight by making them as minimal as possible, but the combination of field takeoff, Eve's gravity, and the physics transition coming off of rails fully fueled are giving me some hassles. I've got 5.15km/s of vacuum deltaV and am carrying a 2.5m ISRU, two fullsized drills, 3 fuel-cell arrays, and 2 large fixed radiators, which gives me an efficient, closed-cycle ISRU unit. Careful fuel-flow design keeps my CoM shift during flight minimized.

The hopeful end goal is a ship which can land on Eve, get to orbit, and then repeat it indefinitely, without the support of a mothership of any description.

Have you already tested if it will make it to orbit?

 

4 hours ago, SingABrightSong said:

Well then, it appears that you have won Kerbal Space Program. I hate to be "that guy", but is there any chance you'd be willing to share your .craft file? Or are you holding off until you've fully refined the design?

I'm actually refining it. I'm planning to release some of my designs someday.

But it's not that hard to rebuild if you have a look at both videos 

[Brainlord Mesomorph]

Now  that we've established it's possible, but not from sea level:

CHALLENGE IDEA:

THE EVE SSTO LIMBO CONTEST!
How LOW can you GO? (and still make orbit)

I'll bet we see some very interesting ideas!

Edited August 26, 2016 by Brainlord Mesomorph

[GoSlash27]

2 hours ago, Brainlord Mesomorph said:

Now  that we've established it's possible, but not from sea level:

CHALLENGE IDEA:

THE EVE SSTO LIMBO CONTEST!
How LOW can you GO? (and still make orbit)

I'll bet we see some very interesting ideas!

 Actually, it was already established that it was possible, and there's already an Eve SSTO limbo contest.

Nevertheless, it's probably a good idea to restart it since it's old.

Best,
-Slashy

[foamyesque]

4 hours ago, Kergarin said:

Have you already tested if it will make it to orbit?

No, because I couldn't get it to survive coming out of timewarp easily. I was working on that.

Then, today, I realized I could just turn on unbreakable joints. Result: I need to revise the design. Higher TWR is needed; the deltaV numbers are ballpark correct but I'm suffering ugly drag losses because I can't pitch up soon enough.

[GoSlash27]

35 minutes ago, foamyesque said:

No, because I couldn't get it to survive coming out of timewarp easily. I was working on that.

Then, today, I realized I could just turn on unbreakable joints. Result: I need to revise the design. Higher TWR is needed; the deltaV numbers are ballpark correct but I'm suffering ugly drag losses because I can't pitch up soon enough.

Yeah... FWIW you're going to have that so long as you're flying out of the atmosphere instead of launching ballistically. Flying always raises the total DV budget.

Best of luck to you!

-Slashy

[foamyesque]

Just now, GoSlash27 said:

Yeah... FWIW you're going to have that so long as you're flying out of the atmosphere instead of launching ballistically. Flying always raises the total DV budget.

Best of luck to you!

-Slashy

 

I'm aiming for a sort of sine curve. The wings are only supposed to be needed to get out to a reasonable horizontal velocity (at which point, due to rocket equation, I've already dumped a bunch of fuel and gotten lighter), at which point I pitch up to do a more traditional ballistic trajectory. I've done this with multistage Eve rockets, and it works just fine, but the TWR curves here are different. The other big thing the wings do is allow for a no-fuel descent.

Ah well. Back to fiddling!

[GoSlash27]

16 minutes ago, foamyesque said:

 

I'm aiming for a sort of sine curve. The wings are only supposed to be needed to get out to a reasonable horizontal velocity (at which point, due to rocket equation, I've already dumped a bunch of fuel and gotten lighter), at which point I pitch up to do a more traditional ballistic trajectory. I've done this with multistage Eve rockets, and it works just fine, but the TWR curves here are different. The other big thing the wings do is allow for a no-fuel descent.

Ah well. Back to fiddling!

foamyesque,

 Far be it from me to tell you how to design your ship. I'm sure you're waiting for the "but", but there isn't one. Spacing is hard, especially if it's in a single stage from Eve. Just be aware that flying from your starting point requires more DV than you might expect, so it'd be in your interest to pack extra.

Flying from a mountaintop is very difficult, but possible. @astrobond did it back in 1.04.

Best,
-Slashy

[Kergarin]

8 hours ago, foamyesque said:

 

I'm aiming for a sort of sine curve. The wings are only supposed to be needed to get out to a reasonable horizontal velocity (at which point, due to rocket equation, I've already dumped a bunch of fuel and gotten lighter), at which point I pitch up to do a more traditional ballistic trajectory. I've done this with multistage Eve rockets, and it works just fine, but the TWR curves here are different. The other big thing the wings do is allow for a no-fuel descent.

Ah well. Back to fiddling!

The sine curve is exactly what I have tried in my first ~50 plane attempts. I then realized that ascending in a direct line and the go into a gravity turn is much more efficient. After ~100 more attempts I started to test out how rockets work on eve, and quickly gave up the idea to use a plane.

Since all this was from 6.800m, I have now tested  some of my plane designs from 7.500m, and they do not perform any better than from 6.800.

[KerikBalm]

20 hours ago, Sharpy said:

I'm still thinking of infrastructure-based approach. Fully reusable stuff deployed to the surface that helps the SSTO back into the orbit. Like a really, really big truck. Maybe even boat-truck, as loading should be easier in case the SSTO splashes down.

I once tried making a rocket sled to get an "SSTO" to orbit on eve.

This is back when I was trying to make a winged SSTO similat to Astrobond's 1.04 SSTO.

Basically, two long sets of structural pieced on rover wheels with struts between them making them rigid - such that it forms a sort of cradle for the SSTO.... I would drive it under the "SSTO" and then extend the airplane landing gear to lift the "SSTO".

This contraption also had rockets, fuel tanks, and parachutes. The idea was to try and accelerate the cart and SSTO up to about 200 m/s as its going up to the peak of the highest eve mountain... then deploy the braking chuts on the cart and quickly switch to the SSTO which would fire its engine and pitch up. I was hoping that if I gave it 200 m/s starting velocity and some vertical velocity, that would amount to at leas an extra 50m/s left at apoapsis.

Ideally, I could switch back to the cart after attaining orbit, drive it back into position, refuel it from ISRU ,repack the braking chutes, etc etc.

I never got it to work.

[Brainlord Mesomorph]

10 hours ago, GoSlash27 said:

and there's already an Eve SSTO limbo contest.

oh, maybe it just sounded familiar. 

[Brainlord Mesomorph]

OK just final word from me on this guys, When I posted the OP I had no idea I was going to start THIS.  I figured I was just going to get a yes or no.

I had an idea for a mission when I started, and that was to parachute the thing in fully fueled. So, I've been trying to scale down Kergarin's design to something that would fit behind the inflatable heat shield. and so far that has eluded me.

scaling it down to 1/6 (6 vectors) or 1/8 (1 mammoth) I can get with a ton or so of the right weights, wet and dry, but then I had the unforeseen problem of BODY LIFT pulling the thing out from behind the heat shield! the solution to that was air-breaks on the nosecone facing downward, but between that, the parachutes and the struts it needed to survive impact landing ADDED FIVE TONS!

Which totally screws up the dV and the TWR. 

I'll revisit this later in my career game when I have an Eve windows coming up. But for now it looks like landing on engines, and some kind of ISRU (perhaps a permanent base) is required. 

Thanks EVERYBODY

[GoSlash27]

@Brainlord Mesomorph, just one quick question before you go:

What's the point? I'll open up this question to anyone who's interested.

It seems to me that a 100% reusable Eve lander is of dubious value if it can only land in one place. Why would you ever need to land on and return from the same place more than once?

Is it just an engineering exercise to prove that it can be done, or does it have some utility that I'm not seeing?

Thanks,
-Slashy

[Brainlord Mesomorph]

@GoSlash27 I'm all about reusablity.

I was hoping we could get down to about 5k which give you a few places to land, hopefully one is within driving distance of someplace interesting. A base is another idea (and that solves the fuel problem). 

And as I said in the OP, a ship that can do this could also do Tylo, is Kerbin SSTO etc. a single ship (ok two ship) Grand Tour mission. 

EDIT: exploring the entire planet w/ boats planes, rovers, hoppers, from "7K Base" where they have fuel and a lab (and regular shuttle service) how's that for a late-career plan?

Edited August 27, 2016 by Brainlord Mesomorph

[GoSlash27]

7 minutes ago, Brainlord Mesomorph said:

@GoSlash27 I'm all about reusablity.

I was hoping we could get down to about 5k which give you a few places to land, hopefully one is within driving distance of someplace interesting. A base is another idea (and that solves the fuel problem). 

And as I said in the OP, a ship that can do this could also do Tylo, is Kerbin SSTO etc. a single ship (ok two ship) Grand Tour mission. 

Fair 'nuff, but none of these strike me as "practical" goals. Well.. the *first* one does. I can see a reusable taxi if it can hit several biomes, but this doesn't do that.

A surface base could be served just as well (and more easily and flexibly) by a disposable lifter and "grand tour" missions are, by nature, impractical.

Not crapping on the concept, mind you. I've pursued many "impractical" goals myself. I'm just trying to understand the nature of it.

Best,
-Slashy