Eve SSTO?

[Der Anfang]

Is it at all possible? Stock, no glitch/bug exploits of any kind. All simply legit. This may sound silly, it's probably been asked before, but I am new here. And after seeing scott manley, MrOverfloater... well, it just makes me wonder if somebody was just clever enough to create an SSTO for Eve, especially since many of these well known youtubers make these kinds of challenges look so easy.

[Starhawk]

Not. Even. Close.

May I direct your attention to this thread?

Happy landings!

[Othuyeg]

Here are a few topics on the subject:

http://forum.kerbalspaceprogram.com/threads/34221-Eve-SSTO-possibility

http://forum.kerbalspaceprogram.com/threads/26365-Is-it-Possible-to-have-an-SSTO-landed-and-come-back-to-a-100km-orbit-from-EVE

http://forum.kerbalspaceprogram.com/threads/84964-Has-it-been-proved-mathematically-that-an-Eve-SSTO-is-impossible

[breakthrough]

There is an absolute maximum delta-v for a single stage based on the ratio of wet mass to dry mass, so no amount of cleverness will get 12,000 delta-v even with aerospikes and an unlimited number of fuel tanks.

[Mister Dilsby]

Briefly, no. But I'll show my work.

Well first off, jets won't work so you are stuck with rockets. Let's suppose you came up with a crazy spaceplane that uses LV-N engines (Isp=800). You need 12,000 m/s delta V to get to orbit from sea level. Let's say you launch from a high mountain, and only need 9000. The Tsiolkovski equation gives,

dV=g*Isp*ln(mass_full/mass_empty)

9000=9.81*800*ln(m_f/m_e)

1.14=ln(m_f/m_e)

exp(1.14) = mass_full/mass_empty

mass_full/mass_empty = 3.13

So your ship would need to be 68% fuel at takeoff.

Now, working around a single LV-N with 60kN of thrust and a mass of 2.25t. Let's assume your wings, control systems, and cockpit are all massless. Rocket fuel tanks have a full to empty ratio of 9:1.

Recalling we need an overall full to empty ratio of 3.13: looks like you need thirteen FL-T100 to get that ratio (or the equivalent). That gives a total takeoff mass of 9.56t and an empty mass of 3.06t.

BUT that 9.56t of mass weighs 159.7kN on Eve! (9.56t*16.7m/s2) And your LV-N only has 60kN of thrust. I don't think any wings made can lift you very high with a thrust to weight ratio that poor, before you run out of fuel. Especially the massless ones I just loaned you. And then you still have to get to orbit when your wings stop working--not trivial with a TWR much less than 1.

Similar problem if you use a higher thrust, lower specific impulse engine like the aerospike. That exercise I leave to the reader

For calculations like the one I just made, crack open a physics text and/or refer to this excellent guide: http://wiki.kerbalspaceprogram.com/wiki/Cheat_sheet

[Lohan2008]

Simple answer is NO.

[GoSlash27]

A legit stock Eve SSTO is impossible in KSP .90, but that may change in 1.0.

The only way to get close is by using ion engines on a glider. Since nobody's successfully made an Eve SSTO ion/infiniglider, it's clearly impossible without the use of infiniglide.

Best,

-Slashy

[Mister Dilsby]

A legit stock Eve SSTO is impossible in KSP .90, but that may change in 1.0.

The only way to get close is by using ion engines on a glider. Since nobody's successfully made an Eve SSTO ion/infiniglider, it's clearly impossible without the use of infiniglide.

I had been working on an attempt using ions for some time actually; not as SSTO, but just using the ions to get a rocket stage high enough to reach:

This one got to about 23,500 on ions and the rocket stage was just short by 500 m/s or so. I put the tests on hold when I found out that V1 would have an aero overhaul. Am hoping that the improved drag and lift models will help this type of craft

[Nansuchao]

This is impossible with stock games, you can achieve this with some mods.

[Norpo]

I always wondered, would it be possible to make a

, and put a rocket on top of that, to gain altitude, and thus reduce delta-v budgets?

I tried making an Eve helicopter, but it always ended badly, but i'm sure someone could make one that works..

Edited March 18, 2015 by Norpo

[Admac]

I've done it in the context of mining Karborundum off the surface. You need the USI Freight Transport Tech pack to make that work. It was an electric powered ducted fan to 16 KM altitude and then the K+ fusion engines for the final ascent. While using two different modded propulsion isn't exactly stock it was still an enormous engineering challenge that took a lot of revisions to make work reliably. I'd recommend the experience to anyone that is looking for a challenge. Lifting off even a few dozen tons of useful cargo is no small feat!

[jarmund]

I am currently working on the same principle as kuzzter, and preliminary tests are promising.

The big differences for me are:

* I can ditch stuff along the way. I have wings attached to radial decouplers, so as i gain speed and need to reduce drag, i ditch the largest set. When it's time to fire the rocket stage i ditch another stage, leaving me with the bare minimum. This reduces the lift, but also the drag, in addition to giving me higher TWR for the rocket stage.

* I only need the kerbal to get to the mothership, so I count his EVA fuel as part of the staging. Also, the mothership has a very maneuverable utility-vessel attached to it that can pick up the kerbal, so i have some additional leeway there

* I'm using FAR, so lift actually increases properly with speed.

[Mister Dilsby]

I am currently working on the same principle as kuzzter, and preliminary tests are promising.

The big differences for me are:

* I can ditch stuff along the way. I have wings attached to radial decouplers, so as i gain speed and need to reduce drag, i ditch the largest set. When it's time to fire the rocket stage i ditch another stage, leaving me with the bare minimum. This reduces the lift, but also the drag, in addition to giving me higher TWR for the rocket stage.

* I only need the kerbal to get to the mothership, so I count his EVA fuel as part of the staging. Also, the mothership has a very maneuverable utility-vessel attached to it that can pick up the kerbal, so i have some additional leeway there

* I'm using FAR, so lift actually increases properly with speed.

I am with you entirely on points 1 and 2! In fact I am ditching 'pods' of empty xenon tanks and even engines as I lift. And yes, if the kerbal is already in a chair no harm using EVA fuel...though I do want to eventually be able to lift a Mk1 capsule, really it does stretch my imagination for the suit to protect the wearer for that long in such a tough environment.

[Deutherius]

I always wondered, would it be possible to make a

, and put a rocket on top of that, to gain altitude, and thus reduce delta-v budgets?

I tried making an Eve helicopter, but it always ended badly, but i'm sure someone could make one that works..

I don't think so. The problem with that concept is that your heli "stage" must be able to lift itself and the rocket stage into high enough atmo, and at the same time your rocket stage needs to be able to lift itself and the heli "stage" from high atmo into orbit. Electric helicopters barely have enough power to lift themselves in 1 atm, much less a rocket stage big enough to achieve orbit around Eve from that altitude.

Ion planes are probably a better choice, though they do face the same problem. I'm certainly interested to see people try whatever is on their mind.

And remember, gentlemen, that dropping any parts disqualifies the vessel as an SSTO. Reaching orbit with a kerbal EVA makes the craft Single Stage to Suborbital at best (impressive as well, but not as prestigious). And using FAR certainly doesn't count as stock (at least until KSP 1.0).

The first person to achieve a truly stock and exploitless Eve SSTO (if anyone ever makes it) is bound to become a KSP legend.

Edited March 18, 2015 by Deutherius

[jarmund]

...snip... it does stretch my imagination for the suit to protect the wearer for that long in such a tough environment.

I'm using TAC Life Support, so i let the mod worry about the realism. That being said, I'm hoping to go for a pod in time myself. I keep having this image in my head of a guy, in a last ditch effort, jumping out on top of a balistic trajectory, desperately taking with him what science he can. When the utility-craft comes along to pick him up, they'll have to dive down steeply to recover a kerbal with his arms full of science reports, all in paper format. Precious intercept before they all burn up in the (presumably) toxic eve atmosphere.

[Mister Dilsby]

And remember, gentlemen, that dropping any parts disqualifies the vessel as an SSTO.

Oh, I have no illusions of single stage--I'm just trying to make my first stage(s) a tad more elegant.

- - - Updated - - -

I'm using TAC Life Support, so i let the mod worry about the realism. That being said, I'm hoping to go for a pod in time myself. I keep having this image in my head of a guy, in a last ditch effort, jumping out on top of a balistic trajectory, desperately taking with him what science he can. When the utility-craft comes along to pick him up, they'll have to dive down steeply to recover a kerbal with his arms full of science reports, all in paper format. Precious intercept before they all burn up in the (presumably) toxic eve atmosphere.

Lovely image! Well if you're using TAC you have enough problems, no need to inject anything additional

[GoSlash27]

Ion planes are probably a better choice, though they do face the same problem. I'm certainly interested to see people try whatever is on their mind.

It's been tried.

http://forum.kerbalspaceprogram.com/threads/85728-Ion-glider-collier-trophy!

We managed to create the first true ion glider SSTOs from Kerbin (both manned and unmanned), but that was just barely possible. Eve is far beyond that.

Maybe after the 1.0 aero revamp, but certainly not before...

If you ever want to try a seriously difficult but just barely possible technical challenge, I recommend this. It's where I learned most of what I know about stock KSP aerodynamics.

Best,

-Slashy

[Deutherius]

It's been tried.

http://forum.kerbalspaceprogram.com/threads/85728-Ion-glider-collier-trophy!

We managed to create the first true ion glider SSTOs from Kerbin (both manned and unmanned), but that was just barely possible. Eve is far beyond that.

Maybe after the 1.0 aero revamp, but certainly not before...

If you ever want to try a seriously difficult but just barely possible technical challenge, I recommend this. It's where I learned most of what I know about stock KSP aerodynamics.

Best,

-Slashy

I was referring to an ion+rocket combo for eve, not just pure ion. It's probably still impossible, but (at least in my head) it sounds less impossible than the electric heli+rocket idea.

As for ion Kerbin SSTO, I've already tried something like that! It wouldn't fit the rules of your challenge, though, had some controllable winglets for wings. I also failed to get it into orbit (ran out of sunlight and I didn't feel like reverting and wasting another hour), but maybe I'll consider giving it another go.

[Gryphorim]

This is impossible with stock games, you can achieve this with some mods.

Specifically Hooligan Labs lighter than air parts.

http://forum.kerbalspaceprogram.com/threads/53961-0-25-and-partial-0-90-HooliganLabs-Mods?highlight=lighter+air

Lets you try one of these:

[Mister Dilsby]

It's been tried.

http://forum.kerbalspaceprogram.com/threads/85728-Ion-glider-collier-trophy!

That is amazing stuff, thanks for sharing that! Lots of good design points going through that thread. I take it you banned horizontal control surfaces to avoid infiniglide abuses?

I'll come back to it after 1.0, but it seems that if you could get a glider into orbit without dropping parts AND without decent control surfaces, it should be more possible than I thought to make an extremely high flier for Eve by allowing myself both of those options. We'll see!

[quasarrgames]

Not now, but quite possibly in the near future of ksp development!

We all know that we're getting new aerodynamics in the next update...

...if these aerodynamics are anything at all like FAR or NEAR, then it should take about 8km/s to get from sea level to orbit...

...which means that it should take 6.5km/s from the tallest hill on eve...

...and this IS ACHEIVABLE with a TWR high enough to lift off from eve (although just barely).

So to sum up, it will be just possible in 1.0 (or now with FAR or NEAR).

[ancient_hunter]

This one uses some slight clipping but its very reasonable and the creator specifically went out of their way to make sure all intakes and engine placement were "realistic"

Great little space plane:

http://forum.kerbalspaceprogram.com/threads/107532-Archangel-Interplanetary-SSTO-Spaceplane-Updated-18-01-2015

[InterCity]

It's not possible in stock, however FAR allows spaceplanes to flash through the slick atmosphere. But even then it's hard to do it. I'd suggest doing that with a multistage plane, like jettisoning its rear part when you run out of its fuel.

[Mister Dilsby]

This one uses some slight clipping but its very reasonable and the creator specifically went out of their way to make sure all intakes and engine placement were "realistic"

Great little space plane:

http://forum.kerbalspaceprogram.com/threads/107532-Archangel-Interplanetary-SSTO-Spaceplane-Updated-18-01-2015

No doubt it gets to Kerbin orbit just fine. On Eve the intakes might be useful as air brakes on the way down, and the jet engines are just 2.4 tons more of mass that will NOT be getting to orbit

[ancient_hunter]

No doubt it gets to Kerbin orbit just fine. On Eve the intakes might be useful as air brakes on the way down, and the jet engines are just 2.4 tons more of mass that will NOT be getting to orbit

Oh yeah you wont be landing, just getting into orbit, I guess I misunderstood the question, that would seem like a tall order with SSTO