Practical (mod) Eve SSTO?

[Sharpy]

@Kergarin managed a stock Eve SSTO; a monstrosity of 8 Mammoths and nearly 1500 tons. To work, it needs to land on, and start from the highest peak of Eve. It's an impressive feat, but hardly practical.

I'm not a purist. I'm much more into practical, friendly solutions. Can we get something more practical?

- doesn't need to be stock

- doesn't need to be strictly SSTO - but should be easily refurbished in orbit (say, using KIS). Some droptanks, SRBs or such are okay, but not losing 95% of the craft as usual stock Eve landers tend to,

- may use Eve ground infrastructure for refueling/resupply/refurbishing (but must be able to reach it - or the infrastructure must be able to reach it!)

but

- shouldn't be bound to one narrow landing location (although some restrictions may apply; like, say, >2500m).

- shouldn't be excessively large

- should be able to carry some modest usable payload. Say, one small MK2 bay full of extra payload, and(/or?) a Kerbal passenger*.

_{*(able to deliver / recover kerbals to/from surface; pilot+passenger or probe core capable of landing/return+passenger)}

Can we do it?

 

---

My first approach was with Nuclear Thermal Jet, 'Roentgen' engine from MK2 Expansion.

Using no fuel whatsoever, from sea level the plane can reach 26km of altitude, corresponding to Kerbin's ~12km. Better than any mountain, and atmospheric pressure there grants over 90% of vacuum performance for NTR engines (LV-N and mod counterparts).

Unfortunately, the thermal jet is a *weak* engine. It's not even supersonic, and since it doesn't require fuel - my test plane didn't carry any fuel. Mere 8.5 ton total.

I tried developing the nukejet+NTR SSTO, and failed miserably. The tests were on Kerbin - but the difference was pretty much moot; the thermal jets work great on Eve sea level; if it can take off from Kerbin, it can take off from Eve sea level. And if it can't reach Kerbin orbit from 12km, sure as hell it won't reach Eve orbit from 26.

- if I load up enough nukes and fuel to have enough delta-V to reach orbital speed from 12km, the thermal jets fall short, unable to lift me above 4km.

- if I add jets, my mass grows so much the nukes can't breach 1 mach.

- if I add lifting surface, my drag grows so much both jets and nukes fail to keep up.

- If I add (or increase size of) nukes or thermal jets to catch up with THAT, I'm rapidly departing the 'reasonably sized' area.

Probably I need something more. A third type of engines maybe?

I'm pretty much stuck. Can you help me?

[Terwin]

Try Kerbal R&D, use science to improve various parts.

including(per part):

weight(limited to 90% reduction),

Atmosphere ISP(increases thrust)

Space ISP,

fuel flow(+50% is the same as an extra half engine for every mounted engine of that type),

Fuel Pressure(increasing how much fuel fits in a specific tank)

ISRU conversion(how much fuel you get per unit of ore, yes this means you make more fuel mass than the starting ore mass)

 

I currently have a LV-N powered vessel with fewer engines than I would normally take to the mun, which is capable of landing and refueling on Tylo, including the USI Life support parts to get there and back in comfort.

I expect that aerospike engines with a nice boost to fuel flow and atmospheric efficiency could get a vessel with all of it's parts reduced to 50% of normal dry-weight into eve orbit without staging.  Could probably even haul up it's own (weight reduced) ISRU and drills...

 

May need to use the cheat menu to get enough science to upgrade that many parts as much as would be needed however...

 

 

[Nansuchao]

With Interstellar Extended is fairly easy to build a spaceplane able to take off from Kerbin, land on Eve and comeback without refuel and with some payload.

[Foxster]

Once you say mods and tweaks are OK then there's little point to this. You can turn on infinite fuel in the debug menu if you just want to get to orbit in a "cheaty" way. 

I know I bang on about this but the point of Eve is that it is hard. If you make it as easy as the other planets by using unbalanced parts then what's the point of doing it at all?

[Sharpy]

4 minutes ago, Foxster said:

Once you say mods and tweaks are OK then there's little point to this. You can turn on infinite fuel in the debug menu if you just want to get to orbit in a "cheaty" way. 

I know I bang on about this but the point of Eve is that it is hard. If you make it as easy as the other planets by using unbalanced parts then what's the point of doing it at all?

Oh, the point isn't to cheat your way out of Eve for free.

It's about doing it with least number of least cheaty mods as possible.

Both Kerbal R&D and Interstellar Extended are extremely OP mods. They are both for use with much harder play modes than plain stock. Either outer planets, or 64k or such - and totally unbalance the gameplay for stock Kerbin system.

If we were to follow your logic to the extreme, there's absolutely no point to any mods after Hyperedit.

[quasarrgames]

There's an easier way that you can do this, in stock. All you need to do is edit the config file.

It's simpler than it looks. Just save an engine, in my case a Nerv, as a subassembly. Then go to saves>your save>subassemblies and open it up.

You'll see something like this:

PART
{
	part = nuclearEngine_4293974652
	partName = Part
	pos = 2.9561553,8.72954178,4.17365026
	attPos = 0,0,0
	attPos0 = 2.9561553,8.72954178,4.17365026
	rot = 0.707106829,0,0,0.707106829
	attRot = 0,0,0,1
	attRot0 = 0.707106769,0,0,0.707106769
	mir = 1,1,1
	symMethod = Mirror
	autostrutMode = Off
	rigidAttachment = False
	istg = 1
	resPri = 0
	dstg = 0
	sidx = 0
	sqor = 0
	sepI = -1
	attm = 0
	modCost = 0
	modMass = 0
	modSize = 0,0,0
	EVENTS
	{
	}
	ACTIONS
	{
	}
	PARTDATA
	{
	}
	MODULE
	{
		name = ModuleEngines
		isEnabled = True
		staged = False
		flameout = False
		EngineIgnited = False
		engineShutdown = False
		currentThrottle = 0
		thrustPercentage = 100
		manuallyOverridden = False
		stagingEnabled = True
		EVENTS
		{
		}
		ACTIONS
		{

You see how thrustPercentage is at 100%? You can bump that up to 500 or 100000%. Same with almost everything else. Increase the efficiency of fuel tanks by cramming more fuel in them. Make solar panels and ISRU work better by increasing their output. I was able to make an SSTO with nothing but a few fuel tanks and a Nerv (yeah, the i-work-very-very-badly-in-atmo Nerv) that had over 3500m/s of delta v in orbit with this technique

[Starman4308]

Maybe Real Fuels with the stockalike configs (at least once they're updated to 1.2)? I regularly pack 6 km/sec into cryogenic upper stages, and I've come close to Kerbin SSTOs in 6.4x scale. Given that I'm hardly the world SSTO expert, I suspect it may be possible to get off 6.4x Kerbin, and by extension, stock Eve.

[Sharpy]

9 minutes ago, quasarrgames said:

There's an easier way that you can do this, in stock. All you need to do is edit the config file.

It's simpler than it looks. Just save an engine, in my case a Nerv, as a subassembly. Then go to saves>your save>subassemblies and open it up.

You'll see something like this

 

Eh. Or I could just hyperedit the craft into orbit. That's not the point!

 

It seems like people assume "Mods allowed = every dirty trick is fine".

No. There are cheat mods, and there are balanced mods that enhance the gameplay, providing new mechanics, based on science and reasonable gameplay balance. They provide more options to solve a problem, but they don't make the problem easy. Eve SSTO in stock is nearly impossible, and requires a huge craft. That means, with a decent set of mods, leaving Eve in a moderately sized craft would be damn hard.

If your first reaction is "Hey, that's easy!", you're probably thinking of a cheat mod.

Edited December 6, 2016 by Sharpy

[Starman4308]

9 minutes ago, quasarrgames said:

There's an easier way that you can do this, in stock. All you need to do is edit the config file.

There is a name for something that modifies configuration files. It's called a "mod".

It ain't stock anymore when you do that.

Sure, most current mods exist as sets of DLLs, configuration files, and models, but in the early days before Module Manager (endless thanks to Sarbian and ialdabaoth for that), you would have had to over-write stock .cfg files; Module Manager just lets you modify them at load-time instead of altering the original files.

Back to Sharpy: there were some inflatable balloon/blimp mods at some point (no idea if they're still up-to-date), and maybe you could use a balloon to ascend to upper Eve atmosphere, deflate the balloon, and then go for orbit.

 

[PocketBrotector]

5 hours ago, Starman4308 said:

Back to Sharpy: there were some inflatable balloon/blimp mods at some point (no idea if they're still up-to-date), and maybe you could use a balloon to ascend to upper Eve atmosphere, deflate the balloon, and then go for orbit.

Now we're talking...

If you launch a rocket from a zeppelin, that counts as reusable launchpad infrastructure instead of staging... right?

In any case, I think that getting "free" altitude might be the key here. Eve's atmosphere is extremely punishing to stock-balanced engines - I spent a while looking at both aerospikes and conventional-bell heavy-launch engines from stock, RLA, Mk4, and SpaceY, but none of them had both the deep-atmospheric thrust to launch from Eve sea level and the Isp to get more than ~4500 dv before hitting the practical limits of the rocket equation.

On the other hand there are Eve Optimized Engines, which I haven't looked into.

[fourfa]

I was going to post Eve Optimized Engines.  That's a mod that makes sense, stock-ish and balanced, but opens up the design space a lot.

Also there's Porkjet's Atomic Age - whose nuclear turbojets are giant and crushingly heavy; worth a glance.  Some of this mod (the Lightbulb) is pretty OP in an otherwise stock game, but less so when you have kilotons of mod greenhouses etc to shove between planets.

[Sharpy]

5 hours ago, PocketBrotector said:

Now we're talking...

If you launch a rocket from a zeppelin, that counts as reusable launchpad infrastructure instead of staging... right?

 

Definitely so! A permanent aerial station with a landing for nukejets and launchpad for SSTO rockets?

Aaaand.... getting the Zeppelin on Eve... that's gonna be tricky.

[magnemoe]

5 hours ago, Sharpy said:

Definitely so! A permanent aerial station with a landing for nukejets and launchpad for SSTO rockets?

Aaaand.... getting the Zeppelin on Eve... that's gonna be tricky.

Put an inflatable blimp inside an fairing with an heatshield. 
Problem is that if you launch from an blimp you will loose the blimp during accent 

[Sharpy]

15 minutes ago, magnemoe said:

Put an inflatable blimp inside an fairing with an heatshield. 
Problem is that if you launch from an blimp you will loose the blimp during accent 

I think there was a mod called 'air parking' or something like that. Or maybe @Angel-125 has some other plans for dealing with that problem?

[JacobJHC]

Not quite an SSTO but it's stock.

[Sharpy]

2 hours ago, JacobJHC said:

Not quite an SSTO but it's stock.

Not quite practical too

 

[Vanamonde]

This exchange of spacecraft has been moved to Spacecraft Exchange. 

[JacobJHC]

21 hours ago, Sharpy said:

Not quite practical too

 What is your definition for practical for this thread? I am confused.

[Sharpy]

21 minutes ago, JacobJHC said:

 What is your definition for practical for this thread? I am confused.

Say, you want to maintain a base on surface of Eve, exchange the crew, deliver goods, lift science off the surface, generally have a 'connection with Kerbin'.

What craft would allow that?

Certainly not one that takes 3 years to refuel.

Certainly not one that requires more than 20 tries to get the landing spot right.

Not one that is required to land at a spot on a single top of a mountain in the middle of a sea, with terrible access to other biomes.

Not one that requires a class E asteroid worth of resources to refuel in orbit before landing.

 

The craft you posted was an awesome feat, but - not to belittle it - not something you'd choose as your 'tool for a regular job'.

There were people who performed missions to Eeloo and Laythe on SRBs alone - but nobody does that on regular basis - for the same reason: that's not practical.

Edited December 8, 2016 by Sharpy

[PocketBrotector]

On 12/8/2016 at 9:07 AM, Sharpy said:

There were people who performed missions to Eeloo and Laythe on SRBs alone - but nobody does that on regular basis - for the same reason: that's not practical.

I think you've gotten at the crux of the problem here. Eve return missions are by design the hardest "normal" tasks in stock KSP. Even a fully expendable mission ends up being nearly as tough and/or complex as a "stunt" mission (e.g. SRB-only, SSTA, or minimum-mass, etc.) to a lower-gravity vacuum or near-vacuum body. 

Crewed return missions to multiple biomes on Eve would likely be the ultimate accomplishment for the kerbals' space program, undertaken only after they've explored and possibly colonized most of the rest of the solar system, if only because everything else would be so much easier. In the past I've mulled over what kind of architecture would be required, and the best I can do is along these lines:

1. A base on Gilly to produce fuel and coordinate exoatmospheric operations within Eve's sphere of influence (i.e. recovering kerbals and science results from Eve's orbit after ascent
2. A base on Eve at some high-altitude point to build and launch (disposable) ascent vehicles. This would be by far the biggest part of the operation, requiring lots of mass for the industrial effort required for extraction, refining/processing, and manufacturing
3. One or more vehicles to get around Eve from the main base with crew and science equipment - probably a nuclear-powered prop aircraft for a combination of speed and endurance.

It's a far cry from an SSTO, but it saves you from having to try to land on a mountain peak from orbit. I don't think that stock balance supports the possibility of an Eve SSTO without granting it a significant altitude handicap from launch - the performance of engines at 5 atm of pressure and 2g is basically insurmountable. 

Depending on how generous your interpretation of "stock balance" is, maybe you could do something like use electric propellors to loft an ultra-high-performance NTR (like the Emancipator from Kerbal Atomics) to a useful altitude (10+km?). That would be the Eve analog to a RAPIER-based SSTO: use atmosphere-specialized engines to get as much altitude and velocity as cheaply as possible before switching over to vacuum-specialized engines. But I'm not going to venture a guess on whether either the propellors or the NTR are going to have sufficient performance to make it work - and there are plenty of other design challenges involved, like surviving reentry and/or refueling once landed.

[Sharpy]

Yes - but that difficultycomes in major parts from the limited selection of parts. Mods can make it much easier - without getting into stuff that is 'cheat level' good, just through creative use of new options they provide.

43 minutes ago, PocketBrotector said:

1. A base on Gilly to produce fuel and coordinate exoatmospheric operations within Eve's sphere of influence (i.e. recovering kerbals and science results from Eve's orbit after ascent

Done, fully operational.

Quote

1. A base on Eve at some high-altitude point to build and launch (disposable) ascent vehicles. This would be by far the biggest part of the operation, requiring lots of mass for the industrial effort required for extraction, refining/processing, and manufacturing

I was thinking more in terms of a mobile base - either based on MK4 with nuclear jets, or a blimp. It can land in ore-rich regions to pick resurces, and then reach high altitudes nearly "for free".

Quote

1. One or more vehicles to get around Eve from the main base with crew and science equipment - probably a nuclear-powered prop aircraft for a combination of speed and endurance.

Tested and true, deployment pending. The airplane in the first post. I dropped it from Eve low orbit, so it can survive the entry, then it can operate on Eve indefinitely.

Quote

Depending on how generous your interpretation of "stock balance" is, maybe you could do something like use electric propellors to loft an ultra-high-performance NTR (like the Emancipator from Kerbal Atomics) to a useful altitude (10+km?).

This would be solvable with the blimp and airpark. Or even an MK4 plane-base and FMSR.

The one missing part is 20km->orbit in a craft that is reasonable. Reasonable size, reasonable complexity, no 20 asparagus-staged boosters, no more than one Mammoth. Preferably mostly reusable. Something that can be refurbished on Gilly and Eve without going through 'scrap-rebuild' process of Extraplanetary Launchpads.

Fully disposable vehicles would be okay too as long as they are *simple*. Stuff thatcould be manufactured on Eve surface in bulk.

Edited December 9, 2016 by Sharpy

[PocketBrotector]

52 minutes ago, Sharpy said:

The one missing part is 20km->orbit in a craft that is reasonable. Reasonable size, reasonable complexity, no 20 asparagus-staged boosters, no more than one Mammoth. Preferably mostly reusable. Something that can be refurbished on Gilly and Eve without going through 'scrap-rebuild' process of Extraplanetary Launchpads.

If you can already get it to 15-20km, you're dealing with only .25-.5 atm pressure from your air launch (according to the wiki). At that point a second-stage-to-orbit vehicle seems solvable with a high-end NTR. (Not sure how you'd get it back into or onto a plane or blimp though - some kind of KAS/IR/Konstruction gizmo?)

52 minutes ago, Sharpy said:

I was thinking more in terms of a mobile base - either based on MK4 with nuclear jets, or a blimp. It can land in ore-rich regions to pick resurces, and then reach high altitudes nearly "for free".

Nice. I know that a Mk3 nuclear turbojet is on the roadmap for the Mark IV pack, though I imagine it won't be developed till Nertea's wrapped up primary development for Near Future Tech, which is still months out.

Edited December 9, 2016 by PocketBrotector

[Sharpy]

17 minutes ago, PocketBrotector said:

If you can already get it to 15-20km, you're dealing with only .25-.5 atm pressure from your air launch. At that point a second-stage-to-orbit vehicle seems solvable with a high-end NTR. (Not sure how you'd get it back into or onto a plane or blimp though - some kind of KAS/IR/Konstruction gizmo?)

I'm also dealing with good 5000m/s at high TWR. Atmospheric ascent on wings will be nearly impossible as I'll be dealing with speeds of 3000m/s+ still in atmosphere thick enough that it can burn me to crisp. I need to jump above the atmosphere and get the orbital speed before I fall down. NTRs give the delta-V but not the thrust. Chemical rockets can buy me the thrust but will fall short in terms of delta-V. And if I combine both, mass of the vehicle grows so much I'm falling victim to the tyranny of rocket equation.

As for getting it 'back' - Heisenberg features an airplane landing on top of its envelopes, with full support for airplane carrier landing (arresting rope+hook). In case of MK4, I can land both on the surface and drive up the cargo ramp.

That's why the vehicle should have at least rudimentary airplane-like features. Or be a good VTOL, for landing into (landed) MK4 ventral cargo bay or on top of Heisenberg (landed or high up).

Quote

Nice. I know that a Mk3 nuclear turbojet is on the roadmap for the Mark IV pack, though I imagine it won't be developed till Nertea's wrapped up primary development for Near Future Tech, which is still months out.

I can happily use the MK3 nuclear turbojets from the MK3 Stockalike expansion, or for more thrust, use the MK3 stockalike MK2 tricoupler and run on three MK2 nuclear turbojets from MK2 Stockalike expansion.

The problem is they lose thrust at some 20km of Eve, and generally are subsonic engines - they are good for cruising and climbing to their ceiling, getting out of the soup, but they won't help me in gaining the orbital speed the least bit.

Edited December 9, 2016 by Sharpy

[PocketBrotector]

7 minutes ago, Sharpy said:

I can happily use the MK3 nuclear turbojets from the MK3 Stockalike expansion, or for more thrust, use the MK3 stockalike MK2 tricoupler and run on three MK2 nuclear turbojets from MK2 Stockalike expansion.

I had forgotten about those. Hard to keep track of all the part packs out there - the only nuclear jet I've used is from Atomic Age, which is basically even more of a novelty than what you've described (not enough power to get anywhere fast, too heavy to haul anywhere.)

8 minutes ago, Sharpy said:

I'm also dealing with good 5000m/s at high TWR. Atmospheric ascent on wings will be nearly impossible as I'll be dealing with speeds of 3000m/s+ still in atmosphere thick enough that it can burn me to crisp. I need to jump above the atmosphere and get the orbital speed before I fall down. NTRs give the delta-V but not the thrust. Chemical rockets can buy me the thrust but will fall short in terms of delta-V. And if I combine both, mass of the vehicle grows so much I'm falling victim to the tyranny of rocket equation.

It depends on whether you're willing to go with an gas core NTR, which offers much higher thrust and specific impulse than the puny solid-core NTRs we're used to. Kerbal Atomics has got you covered in a big way.

Put some parachutes on one side and some legs and wheels on the other, and I'm guessing you'd get the bare minimum of surface mobility needed to load it into a Mk4 plane.

[Sharpy]

1 minute ago, PocketBrotector said:

It depends on whether you're willing to go with an gas core NTR, which offers much higher thrust and specific impulse than the puny solid-core NTRs we're used to. Kerbal Atomics has got you covered in a big way.

 

Aren't these tanks really lousy against atmospheric heating?