Is Eve SSTO possible?

[stilgar]

I've searched the internet and people say it's not - but all of those threads are from before 1.0. Did anyone try it in current version of the game? We have ISRU and less drag, so maybe...?

[J-Curwen]

I think its possible but hard. Before 1.0 you needed roughly 10-12km/s deltaV. Looking at the latest map its seems youll only need 6km/s now from sea-level, which is really hard to aquire in athmosphere, I think it close out of reach because youll need some good TWR as well. But it think it could be possible, when starting ontop of a mountian.
The theoretical maximal deltaV you can get with an aerospike is 6250 m/s for a single stage in athmosphere.

[J-Curwen]

Looking through the parts it seems the aerospike got nerfed pretty hard with the lastest patches. The mammoth engine looks like the way to go.

[Surimi]

You have to remember that even on kerbin it's very hard to build an SSTO which doesn't rely on jet engines, because jet engines have extremely high specific impulse relative to rockets. If Eve's atmosphere had oxygen, it might be possible but it doesn't. I haven't done the maths, but my money is on no. A rocket-only SSTO is hard enough to build on Kerbin.

[SievertChaser]

I wonder if all-rocket SSTOs are even worth the trouble...

[Yawzheek]

dennis.danilov님이 먼저 게시:

I wonder if all-rocket SSTOs are even worth the trouble...

I'm definitley not in the know as far as SSTO is concerned, as I've sadly never built one, but would not an all-rocket SSTO be so ungodly large and inefficient to make it completely impractical? I've just always been under the impression that SSTO design was largely built on efficiency and the ability to achieve a high horizontal velocity prior to leaving the atmosphere through fuel-efficient turbine engines that rocket staging was kept to a minimum.

[SievertChaser]

A mere guesstimate is that a jet would be ten times as efficient, based on Isp.

[Migz - DH]

Sandor님이 먼저 게시:

Looking through the parts it seems the aerospike got nerfed pretty hard with the lastest patches. The mammoth engine looks like the way to go.

Actually, the aerospike just received a performance boost in 1.0.3.

* Aerospike mass lowered as a buff (it needed a buff to compete with late-tier engines) and tangents fixed.

[stilgar]

Deep Hurting님이 먼저 게시:

You have to remember that even on kerbin it's very hard to build an SSTO which doesn't rely on jet engines, because jet engines have extremely high specific impulse relative to rockets. If Eve's atmosphere had oxygen, it might be possible but it doesn't. I haven't done the maths, but my money is on no. A rocket-only SSTO is hard enough to build on Kerbin.

I have build a simple rocket Kerbin SSTO - one Mammoth and enough fuel, capsule for 3 kerbals, parachutes and airbrakes. No problem reaching orbit without staging.

Stalinator님이 먼저 게시:

dennis.danilov님이 먼저 게시:

I wonder if all-rocket SSTOs are even worth the trouble...

I'm definitley not in the know as far as SSTO is concerned, as I've sadly never built one, but would not an all-rocket SSTO be so ungodly large and inefficient to make it completely impractical?

It is large and impractical, but I wanted to make a ship that could land and take off anywhere multiple times. I've made supply ship that can land and take off from any planet/moon without atmosphere, but I don't have reusable lander for large planets with atmosphere.
If you just want to go somewhere and back, SSTOs aren't worth it.
If you want to establish permanent bases on distant planets, it's good when you don't have to ship everything from Kerbin.

[Yawzheek]

dennis.danilov님이 먼저 게시:

A mere guesstimate is that a jet would be ten times as efficient.

That's what it sounds to me as well. It just sort of seems to defeat the entire purpose, whereas a jet engine can gradually increase horizontal velocity and altitude with extremely efficient fuel costs, and I'm not certain that rockets in the game - while some are quite efficient as well - lack the same power to efficiency as traditional turbine engines, or are suited well for the task. Honestly, an all-rocket design just sounds like taking a ridiculously large fuel tank (far larger than is practical) and burning all the chemical energy, sounding as though it only equates to slight power gain by loss of mass over wind resistance and gravity. In fact, from the sound of it, the only thing that seems to benefit from an all-rocket SSTO is not needing to switch between rocket and turbine.

I'm no rocket or aviation scientist, by any stretch of the imagination, nor do I make any such claims, but it just seems ridiculously inefficient for the purpose of orbit, when an all-rocket design would achieve the same thing, and likely safer.

[Yawzheek]

stilgar님이 먼저 게시:

Stalinator님이 먼저 게시:

I'm definitley not in the know as far as SSTO is concerned, as I've sadly never built one, but would not an all-rocket SSTO be so ungodly large and inefficient to make it completely impractical?

It is large and impractical, but I wanted to make a ship that could land and take off anywhere multiple times. I've made supply ship that can land and take off from any planet/moon without atmosphere, but I don't have reusable lander for large planets with atmosphere.
If you just want to go somewhere and back, SSTOs aren't worth it.
If you want to establish permanent bases on distant planets, it's good when you don't have to ship everything from Kerbin.

Oh, I've definitely wanted to experiment with them for quite some time. The actual Space Shuttle has never been an exceptionally efficient vehicle either, which has never been a secret, but it's prized because it's reusable, and in terms of KSP and the ability to go SSTO without jettisoning a single part and landing back at the KSC, it's an INCREDIBLY efficient design, from what I can tell. I would even argue an SSTO space shuttle is probably significantly MORE efficient if you want to go somewhere and back (mind you, we're discussing KSP) since the only costs involved are seemingly fuel and how bad you are at landing on the runway/KSC. I mean, if you're willing, able, and capable of landing on another celestial body with it, and returning to the KSC with the same craft, fuel costs aside, it seems almost free, yes?

The whole discussion is interesting to me.

[SievertChaser]

Stalinator님이 먼저 게시:

stilgar님이 먼저 게시:

It is large and impractical, but I wanted to make a ship that could land and take off anywhere multiple times. I've made supply ship that can land and take off from any planet/moon without atmosphere, but I don't have reusable lander for large planets with atmosphere.
If you just want to go somewhere and back, SSTOs aren't worth it.
If you want to establish permanent bases on distant planets, it's good when you don't have to ship everything from Kerbin.

Oh, I've definitely wanted to experiment with them for quite some time. The actual Space Shuttle has never been an exceptionally efficient vehicle either, which has never been a secret, but it's prized because it's reusable, and in terms of KSP and the ability to go SSTO without jettisoning a single part and landing back at the KSC, it's an INCREDIBLY efficient design, from what I can tell. I would even argue an SSTO space shuttle is probably significantly MORE efficient if you want to go somewhere and back (mind you, we're discussing KSP) since the only costs involved are seemingly fuel and how bad you are at landing on the runway/KSC. I mean, if you're willing, able, and capable of landing on another celestial body with it, and returning to the KSC with the same craft, fuel costs aside, it seems almost free, yes?

The whole discussion is interesting to me.

It's a bit impractical, though. The aircraft parts weigh (or at least should weigh) a lot, therefore it's inefficient to haul them around the system. Makes more sense to deliver a payload section to a multi-use nuclear bus, and send the unaerodynamic payload off to its destination.

Not to mention that returning in a damaged shuttle is more difficult than in a Orion-style return vehicle, which is very difficut to completely destroy.

[Empiro]

dennis.danilov님이 먼저 게시:

A mere guesstimate is that a jet would be ten times as efficient, based on Isp.

Yes, but jets don't work on Eve, which is why an SSTO is hard (or maybe impossible) there.

[SievertChaser]

Empiro님이 먼저 게시:

dennis.danilov님이 먼저 게시:

A mere guesstimate is that a jet would be ten times as efficient, based on Isp.

Yes, but jets don't work on Eve, which is why an SSTO is hard (or maybe impossible) there.

We've actually departed from Eve and ended up with a theoretical discussion of SSTO.

[Empiro]

dennis.danilov님이 먼저 게시:

Stalinator님이 먼저 게시:

Oh, I've definitely wanted to experiment with them for quite some time. The actual Space Shuttle has never been an exceptionally efficient vehicle either, which has never been a secret, but it's prized because it's reusable, and in terms of KSP and the ability to go SSTO without jettisoning a single part and landing back at the KSC, it's an INCREDIBLY efficient design, from what I can tell. I would even argue an SSTO space shuttle is probably significantly MORE efficient if you want to go somewhere and back (mind you, we're discussing KSP) since the only costs involved are seemingly fuel and how bad you are at landing on the runway/KSC. I mean, if you're willing, able, and capable of landing on another celestial body with it, and returning to the KSC with the same craft, fuel costs aside, it seems almost free, yes?

The whole discussion is interesting to me.

It's a bit impractical, though. The aircraft parts weigh (or at least should weigh) a lot, therefore it's inefficient to haul them around the system. Makes more sense to deliver a payload section to a multi-use nuclear bus, and send the unaerodynamic payload off to its destination.

Not to mention that returning in a damaged shuttle is more difficult than in a Orion-style return vehicle, which is very difficut to completely destroy.

Yes, this is exactly correct. A 100% reuseable craft is certainly possible, but unless you're going to Laythe and back, it's best to ditch the wings in LKO.

If your interplanetary lander (and also the tug) is fully reusable (e.g. no drop tanks or anything), then you can simply return to Kerbin, aerobrake into LKO, and leave it there. Instead of landing the engines, command capsules, etc on Kerbin only to launch it again, simply send an SSTO space plane up to refuel it.

[stilgar]

dennis.danilov님이 먼저 게시:

It's a bit impractical, though. The aircraft parts weigh (or at least should weigh) a lot, therefore it's inefficient to haul them around the system. Makes more sense to deliver a payload section to a multi-use nuclear bus, and send the unaerodynamic payload off to its destination.

Not to mention that returning in a damaged shuttle is more difficult than in a Orion-style return vehicle, which is very difficut to completely destroy.

The heaviest part of the ship is it's fuel.
We now have ISRU, so if you set up refuelling bases on moons and smaller planets, you don't need to worry about that. You lander needs few thousand dv anyway, so if it can get into orbit and something else is going to refuel it, then it can continue indefinitely, jumping from planet to planet.
If you lander has only small crew capsule or it's AI-controlled, it won't have to be very large. If you want to fly with research lab and ISRU and everything in the Utility tab, then yes, your ship will be huge and you will hit part limit...

And it's definitely less effcient to build new ship every time you want to go to a new location. Even huge amounts of fuel are cheaper than engines, tanks and all that advanced equipment.