Stock SSTO reusable ship from eve

[Pyranz]

The idea of using an ion glider of sorts is to take advantage of Eve's thick atmosphere. One the air has become too thin to glide effectively then you're already past the hardest part of leaving eve, and if you've used ions to get there then the fuel use is tiny, so activate your nerva now that it's not stunted by atmosphere. And as for ions being unrealistic... Seriously? The hardest part of this challenge is getting through an atmosphere of mashed peas.

[problemecium]

What's the deltaV necessary for Eve ascent again? Kerbin's is 4500 m/s, and I heard Eve is 20% more, in which case I think one of my heavy lifters can pull it off if I omit the payload.

[cantab]

I bet the SLS parts could do it, if you could find a way to use spaceplane parts with them.

The problem for a rocket isn't the engines so much as the tanks. They impose a limit on the fuel mass fraction, which in turn limits the delta-V for a single stage without drop tanks. And the ARM tanks are actually worse than the FL-T and Rockomax tanks in that respect.

A rocket plane I doubt will work because of the drag. A proof-of-concept on Kerbin may be instructive: can you reach orbit with a rocket plane (no jets or ions) and use less fuel doing so than with a regular rocket?

What's the deltaV necessary for Eve ascent again? Kerbin's is 4500 m/s, and I heard Eve is 20% more, in which case I think one of my heavy lifters can pull it off if I omit the payload.

You heard way wrong. It's more like 2 to 3 times as much. And you need higher TWR as well.

[guitargun]

So what the best thing to do with is is making a lightweight probe that flies to high altitude then use the nerva engines. I made a design but I came stuck on the electric part. Any tips on that.

[Moar Boosters]

Give up because it's not possible. A single NERVA has enough thrust on Eve to lift a single FLT-100 fuel tank. The next size up, and it's not moving anywhere.

Edited April 26, 2014 by Moar Boosters

[MarvinKitFox]

What's the deltaV necessary for Eve ascent again? Kerbin's is 4500 m/s, and I heard Eve is 20% more, in which case I think one of my heavy lifters can pull it off if I omit the payload.

20% more?

MUHAHAHAAAAHAHAHHAAAAAA HAHAHAAAAAAAAAAAAA {gasp} heheheeeehehehehehehehe!

Try 200%-240% *more*

Try 12000 deltaV, *and* you need a TWR of 2.5(at Kerbin launchpad).

[Pyranz]

You do not need a twr greater than 1 using a glider. You do not need to use a nerva near the surface to use it at all, the option to turn engines off has been in the game a while now.

[rtxoff]

The most minimalist ion glider barely managed to reach orbit on Kerbin and still people here claiming an ion design can lift a nerva + tank into some height on eve. Wake up dreamers, reality is here and reality says no way. So stop this madness here or even try before further defaming yourselves.

Edited April 26, 2014 by gpisic

[NichG]

You can easily lift a NERVA and tank with an ion glider on Eve. Where 'easily' means '20 minutes in game time to ascend 1km'. With Eve's atmosphere, you can glide just fine even with a TWR of 0.02. That's not the problem.

The problem is that once you get up to altitude you won't get any horizontal speed of note. Which means that even where the ISP is close to 800 you're going to need a TWR greater than 1 with the NERVA. Which means you need something like 3-4 NERVAs to a single one of the long 1.5m tanks. Which is no good. The maximum single-stage delta-v you can get while still maintaining Eve TWR>1 is actually much higher for the tiny probe engines than for the NERVAs, taking into account engine mass - its somewhere in the vicinity of 4km/sec.

[RocketPilot573]

Maybe the Ion engines can do it? Remember, you can make the electrical system completely weightless.

[rtxoff]

All i see here is "it's easy" and "maybe" nobody actually building the thing and trying it out seeing how easy an SSTO on Eve really is.

[Pyranz]

Yeah, I plan in remedying that tonight, seeing as I've been away.

[NichG]

I have been doing it and reporting the results so far. But nothing that can make it to orbit, for the reasons I gave.

[KerikBalm]

Problem:

SSTO means your "wet mass" : "dry mass" ratio can never be any better than the best fuel tank (which is not the ARM tanks). When you plug that into the Tsiolkovsky rocket equation, you will find the maximum deltaV a single stage rocket can get.

It is below that required for eve ascent.

http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation

That goes for all the "chemical" engines.

That leaves us with the ions and the nukes.

The nukes get a worse ISP than the chemical until very high on eve, because its atmosphere is very thick.

Ions have plenty of ISP for the tank empty/dry weight

So then the next problem is TWR and gravity drag.

The low nuke TWR knocks them out (even though the low atmospheric ISP already knocked them out of the running).

The stupidly OP'd ions still can't even lift themselves off the ground as a rocket.

So you'd have to use a wings,

In real life, wings can negate gravity drag and provide for a more efficient ascent

That can get you around the TWR requirement.

But then we run into another problem, the KSP aerodynamics model, where drag is proportional to the square of velocity, but lift is proportional to only velocity,

Thus, drag increases much faster than lift, and soon far too much drag is produced just to generate the lift needed, and you don't get to orbit. (at least not with ions, somethign with a better TWR can counteract more drag while still only requiring the same amount of lift, and once you get going fast enough, you don't need so much lift as you're close to orbit anyway, but if you never get close to orbital speed, that wont apply)

It is not possible with stock parts and stock aeordynamics.

Just like in real life its not possible to SSTO with a water+baking soda powered rocket.

Nor is it possible to SSTO from kerbin using just sepratrons

If you want to SSTO on eve, mod yourself an engine with 2,000 atmospheric ISP, and a 50:1 TWR, then you should be able to easily do it.

None of the parts have enough performance to SSTO from eve.

It is impossible without taking advantage of a glitch (like the demonstrated ladder thing, or an infiniglider)

Edited April 26, 2014 by KerikBalm

[rtxoff]

very nice explaination KerikBalm, here take the reputation

[Pyranz]

Ah. I was not aware just how harsh the drag system was. Thank you.

[blitz2190]

I made a ssto VTOL space plane using interstellar among a few other mods , an its a painful 30 minute climb with a took a tooon of weight just to power the engines but it works with enough fumes to fuel up on gilly and my twr was 1 on eve with a DV of 20k used and even with a positive twr I still lose altitude after 30km unless I climb straight up because the unrealistic drag almost negates the lift

Edited May 15, 2014 by blitz2190

[kebabsoup]

Urgh...Only stock parts eh? LoL! And for the hard mode, you have to go refill your SSTO from a base on Jool.

[GoSlash27]

SSTO from Eve all- stock complete with docking port and rendezvous equipment?

Sheesh, I thought you were gonna ask for something difficult!

http://s52.photobucket.com/user/GoSlash27/slideshow/KSP/krakelicious/Eve%20mission

hehe

-Slashy

[Joonatan1998]

You probably could build an eve SSTO by using lots of decouplers. Stage them all at once at the ground.

[Gravaar]

You probably could build an eve SSTO by using lots of decouplers. Stage them all at once at the ground.

Not enough force, you need to overcome Eve atmosphere as well as its massive gravity, and drag is a lot WORSE on Eve at sea level so you lose a lot of energy

0 ASL on Eve ( sea level ) requires something like 12,000 m/s Delta-v and an Eve Thrust to weight ratio of about 1.2 to 1.7 or better ( equal to a Kerbin T/W of about 2.5 to 3 )

Anything less than T/w of 1.2 requires even more Delta-v so an Ion plane with a T/w of 0.2 will require a LOT more delta-v as it wastes fuel not climbing straight up, the advantages of LIFT the wings get is offset by the drag as mentioned in previous post's

TLDR: EVE SSTO not possible with stock (except by glitching infinityglide, alt-f12 or some other "cheat"). EVE staged rocket more than possible, EVE space plane possible (with staging) but harder than a rocket

[Laie]

You probably could build an eve SSTO by using lots of decouplers. Stage them all at once at the ground.

If the stack is some 90km high, this might actually work. But can you land it?

[Gravaar]

If the stack is some 90km high, this might actually work. But can you land it?

Landing is easy, Landing without crashing is hard

[MarvinKitFox]

You probably could build an eve SSTO by using lots of decouplers. Stage them all at once at the ground.

Your mind.

Make it up.

SSTO, or many multiple stages?

'cause stacked decouplers is **********NOT*********** Single-stage-to-orbit.

You might as well claim that you can drive from New york to LA on a single tank of gas, as long as you can make a refuelling stop every 100 miles!

[Joonatan1998]

Your mind.

Make it up.

SSTO, or many multiple stages?

'cause stacked decouplers is **********NOT*********** Single-stage-to-orbit.

You might as well claim that you can drive from New york to LA on a single tank of gas, as long as you can make a refuelling stop every 100 miles!

Decouple 500 decouplers at once, only one press of spacebar, only one stage. If your ship is only made from massless parts it can reach escape velocity.