Eve biome hopping strategy

[fourfa]

Hello all, first post on the forums. I'm doing a big Eve mission to collect science from all the surface biomes. Mission profile is a disposable surface biome hopper, eventually calling down an ascent vehicle from orbit at a suitable LZ. 2 Kerbals - a scientist to reset the experiments, an engineer for the ISRUs and broken things, 2 cabins to recover 2 copies of all experiments (just for fun). I have the ascent vehicle finished - sea level capable, 4 stages with ISRU surface fueling, ~450T and 200 parts at Kerbin launch, ~300T and 80 parts at Eve launch. The surface of Eve in my sandbox/hyperedit testing save is hilariously littered with wreckage and dead Kerbals from the process of designing that craft, but it works every time. The only requirement is landing on no more than a moderate incline.

Oh, and this is a mostly stock game with just GPOSpeedFuelPump, EditorExtensions, KER, MJ. Cost and techs are not factors.

Option 1: I designed and tested a 2-Kerbal rover to drive over all the biomes, and I quickly lost interest in that method. Eve is a big place and rovers can be explodey, though it seems to work with a lot of F5/F9 and it's very simple. Maybe I just need more design work to survive 4x physics warp, and read a book?

Option 2: I designed and tested a vertical-launch 2-Kerbal ISRU suborbital rocket that can fly horizontally for a bit and land on chutes. I went for as small as possible with aerospikes and ~1500m/s sea level dV. Works terrific on Kerbin, but I can't seem to make more than 6-7km per hop on Eve - very tedious. Perhaps a gigantic Mammoth based ship could get a lot more suborbital and cover more ground? Perhaps some big wings could give me more glide distance?

Option 3: I've looked at low-altitude rocket planes with landing gear and a Mk3 ISRU cargo bay. It does seem like the surface is smooth enough that low-speed landing and take-off is possible. But the mass is such that I'm having trouble generating enough lift with something that could survive entry from orbit. Parts count and TWR with spikes seems marginal, craft profile with Mammoth is pretty unwieldy, maaaaybe a Mainsail could work but seems like it might have trouble taking off again at low elevations. But maybe - just maybe - I might get a plane to float around, get data from "splashed-down" biomes, and rocket back to land? Most of the info I've found on flying on Eve is very dated, based on Kethane, strictly about SSTOs, ion gliders, etc.

Option 4 would seem to be wait a week for 1.0.5 and see how the mini-ISRU parts affect the economics of options 2 and 3, though I'm concerned about the reported pickiness with low ore concentrations.

TL;DR: any thoughts on how best to explore the surface of Eve?

Edited November 8, 2015 by fourfa

[Snark]

Agreed that exploring Eve by rover is tedious, though if you're willing to put in a bit of time and choose site carefully, you can hit like 5 biomes within a radius of a hundred km or so.

Making a rover that survives well at high physics warp: keep it as light as possible, the more mass it's carrying per wheel, the more explosion-prone it is. Consider putting some wings on the rover so that it can glide a bit on downslopes, helps to smooth things out a bit (and is also just fun to drive).

If you're willing to add another Mod, Porkjet's Atomic Age has a nuclear turbojet that runs indefinitely without fuel and requires no oxygen... the only downside is that it's slow (under Mach 1), massive (8 tons). You won't get to space in it, but it's a helluva lot faster than a rover.

[magnemoe]

Like the idea of wings on rover, it will help landing as you have crossrange.

it also has another benefit, it make it easy to do in flight science outside the biome you landed in.

Looking at map: you have to do an polar landing anyway.

South pole has highland and lowland close by and you can get impact ejecta from the border zone to the pole.

Midland is around 10 km from the border zone. Now you could get peak and sea in the same round but that would require an trip of around 100 km, with some sort of plane this will be easy.

If not do an second landing at equator for peak midland and sea.

----

One idea for you is to use your accent rocket SSTO suborbital and refill, main issue might be stability also an issue if you can reach all biomes from the fuel sources.

Another idea is an rocket plane you can refuel from the ISRU on the rocket, yes this will limit range but how much do you need?

If you land on the right spot close to the poles every biome is less than 50 km away.

drop the plane inside an fairing, pop it out then you is done with the flames.

[Foxster]

Here's an Eve biome mission I did a little while ago: http://forum.kerbalspaceprogram.com/threads/132072-Eve-for-the-science%21

It might be useful just for the location. You can visit 5 biomes in a short distance. So you could do it via a rover or it wouldn't be far with a hopper.

[fourfa]

One idea for you is to use your accent rocket SSTO suborbital and refill, main issue might be stability also an issue if you can reach all biomes from the fuel sources.

Another idea is an rocket plane you can refuel from the ISRU on the rocket, yes this will limit range but how much do you need?

If you land on the right spot close to the poles every biome is less than 50 km away.

drop the plane inside an fairing, pop it out then you is done with the flames.

Those are interesting ideas, thanks. Pumping fuel around from the upper stages, the 3 Mammoths of the ascent vehicle's S1/S2 would hop a fair distance. Problem is the landing zone and reasonable incline - took some testing to find one from orbit that wouldn't tip, atmospheric entry isn't that predictable, and I was originally figuring to use the rover to find a nice huge flat spot. Hopping in a ~340T skyscraper is pretty chancy.

Refueling a light plane from the ISRU on the ascent vehicle - also an interesting idea I hadn't thought of. That could yield a much bigger range than the monstrosity I've been playing with.

Bringing multiple ascent vehicles - no reason a brute force approach wouldn't work too.

Lots of consider, thanks for all the ideas!

- - - Updated - - -

If you're willing to add another Mod, Porkjet's Atomic Age has a nuclear turbojet that runs indefinitely without fuel and requires no oxygen... the only downside is that it's slow (under Mach 1), massive (8 tons). You won't get to space in it, but it's a helluva lot faster than a rover.

I'll have a look - 8 tons is roughly similar to the ISRU, drills, fuel cells, ore tanks setup but would displace the 15 tons of the Mammoth engine, or ~8T of aerospikes I've needed so far just to get in the air at 100+m/s, and get rid of the colossal sloshing tanks of LF/O.

Edited November 6, 2015 by fourfa

[magnemoe]

Those are interesting ideas, thanks. Pumping fuel around from the upper stages, the 3 Mammoths of the ascent vehicle's S1/S2 would hop a fair distance. Problem is the landing zone and reasonable incline - took some testing to find one from orbit that wouldn't tip, atmospheric entry isn't that predictable, and I was originally figuring to use the rover to find a nice huge flat spot. Hopping in a ~340T skyscraper is pretty chancy.

Refueling a light plane from the ISRU on the ascent vehicle - also an interesting idea I hadn't thought of. That could yield a much bigger range than the monstrosity I've been playing with.

Bringing multiple ascent vehicles - no reason a brute force approach wouldn't work too.

Lots of consider, thanks for all the ideas!

- - - Updated - - -

I'll have a look - 8 tons is roughly similar to the ISRU, drills, fuel cells, ore tanks setup but would displace the 15 tons of the Mammoth engine, or ~8T of aerospikes I've needed so far just to get in the air at 100+m/s, and get rid of the colossal sloshing tanks of LF/O.

Better legs will make it easier to land, main issue as I see it is aerodynamic stability and turning the ship.

All the extra frill is dropped then going for orbit anyway.

Has only done tests for Eve landers in 1.04 found that an lander with 7 aerospikes in aspargus with an 909 upper stage works well, it only an one man craft and contains nothing not used to land or going up. Rest will be on rover.

The atomic turbojet sounds interesting, tried something like this but had stability problems.

Using it would be natural to have three parts of the ship, bottom is for landing and science, middle is the jet engine and fins/ reaction wheels to keep it stable in flight, upper is the orbital rocket. You would drop jet in the upper atmosphere so you can use vacuum engines.

Edit just tested the atomic turbojet. its so weak its you have to use it in a plane, not even sure it will take you to upper atmosphere with an upper stage. I would however be nice for traveling around Eve doing science.

Edited November 6, 2015 by magnemoe

[FlyingPete]

Ion engines work well on Eve for small aircraft, though it's conceivable that a rover will be quicker. I've built a couple of planes with rover wheels so you can retract the landing gear (putting the rover wheels on the ground) and drive around without wasting fuel. If you have ISRU it makes sense to use that to refuel the plane so, landing in the right spot, you can do multiple excursions from the landing site to gather science.

If you're going for maximum science from the surface, bring a research lab with you. You can research the scientific data on the surface (going on in the background during exploration trips) and transmit that to Kerbin, as well as bringing back the data itself.

[TheXRuler]

Well if you are considering mods, check out KSP-Interstellar extended. That gives you a nuclear turbojet to use atmosphere as fuel, but with beamed power (microwaves) you don't need to carry the power generation with you making the system a lot lighter. Also, thrust depends oon how much power you can put in and is essentially only capped by your radator capacities (waste heat)

[fourfa]

Ion engines with 2 Kerbals in separate pods, all science gear, and enough range for about a quarter circumnavigation? With what power source, solar? I'd love to learn how to do it

I will have a research lab in orbit, but basically I'm just aiming to bring back 200 or however many experiments from Eve and Gilly at once.

I looked at the mods mentioned, I think I want to make this happen in a stock-ish game.

Edited November 6, 2015 by fourfa

[Snark]

Better legs will make it easier to land, main issue as I see it is aerodynamic stability and turning the ship.

All the extra frill is dropped then going for orbit anyway.

Has only done tests for Eve landers in 1.04 found that an lander with 7 aerospikes in aspargus with an 909 upper stage works well, it only an one man craft and contains nothing not used to land or going up. Rest will be on rover.

The atomic turbojet sounds interesting, tried something like this but had stability problems.

Using it would be natural to have three parts of the ship, bottom is for landing and science, middle is the jet engine and fins/ reaction wheels to keep it stable in flight, upper is the orbital rocket. You would drop jet in the upper atmosphere so you can use vacuum engines.

Edit just tested the atomic turbojet. its so weak its you have to use it in a plane, not even sure it will take you to upper atmosphere with an upper stage. I would however be nice for traveling around Eve doing science.

Yes, that's right-- as I mentioned in my original post, the atomic turbojet is not for going to space. Not not not. But it's perfect for roaming around Eve and sampling biomes, since it requires zero fuel. It can't get much past Mach 1 at best, but that's still enormously faster than a rover.

The way to use it is to make a small plane that's basically a nuke turbojet, cockpit, science instruments, and nothing else. It flies all over and gathers science from every biome (though it probably can't get up to "upper atmosphere"). When done, fly it to wherever your ascent vehicle is.

The main challenge with the turbojet is getting it to Eve in the first place-- it's big and massive and has no bottom attachment node, so it's fairly awkward as payloads go. (But I guess it's less massive than toting around the fuel to make a 340t skyscraper hop from place to place...)

- - - Updated - - -

Ion engines with 2 Kerbals in separate pods, all science gear, and enough range for about a quarter circumnavigation? With what power source, solar? I'd love to learn how to do it

I will have a research lab in orbit, but basically I'm just aiming to bring back 200 or however many experiments from Eve and Gilly at once.

I looked at the mods mentioned, I think I want to make this happen in a stock-ish game.

Ion propulsion's not gonna work on Eve. It has really crappy atmospheric Isp now (since 1.0), and also solar panels get very limited power on Eve surface (the atmosphere blocks a lot of the sunlight). Ions are good for maneuvering in Eve orbit, but don't even think about trying to use them down on the surface.

[RocketPropelledGiraffe]

Biome hopping on Eve is basically the only reason I would really like to have a stock propeller with electric motor.

I don't care for non-space plane designs, but I think having something to move around on Eve would improve everyone's experience on the purple planet. At the moment the most interesting part is getting away from Eve, there is not much fun in staying there.

[magnemoe]

Yes, that's right-- as I mentioned in my original post, the atomic turbojet is not for going to space. Not not not. But it's perfect for roaming around Eve and sampling biomes, since it requires zero fuel. It can't get much past Mach 1 at best, but that's still enormously faster than a rover.

The way to use it is to make a small plane that's basically a nuke turbojet, cockpit, science instruments, and nothing else. It flies all over and gathers science from every biome (though it probably can't get up to "upper atmosphere"). When done, fly it to wherever your ascent vehicle is.

The main challenge with the turbojet is getting it to Eve in the first place-- it's big and massive and has no bottom attachment node, so it's fairly awkward as payloads go. (But I guess it's less massive than toting around the fuel to make a 340t skyscraper hop from place to place...)

- - - Updated - - -

You are right about the nuclear jet engine.

You can do science from upper atmosphere by dipping down to 89.9 km from orbit.

Use an radial decopler, using an girder frame you could even get it inline for launch then sideway for transfer.

Plenty of wings so landing and takeoff speed is low this also give an wide wheelbase, note that it does not produce power.

Not sure how practical it is to deorbit an plane on Eve, another benefit of large wings.

Note that the plane can be used for science on eve surface later without pilot.

[FlyingPete]

Biome hopping on Eve is basically the only reason I would really like to have a stock propeller with electric motor.

I don't care for non-space plane designs, but I think having something to move around on Eve would improve everyone's experience on the purple planet. At the moment the most interesting part is getting away from Eve, there is not much fun in staying there.

Either that or the option to run a reversed-cycle jet engine- drawing in combustible gases from the atmosphere of Eve (and Jool) and burning it with onboard oxidiser. Currently Ion engines can be made to work, but of course you need to ship xenon fuel supplies from Kerbin.

[Snark]

Either that or the option to run a reversed-cycle jet engine- drawing in combustible gases from the atmosphere of Eve (and Jool) and burning it with onboard oxidiser.

Well, that's making an assumption about the atmosphere content. We don't know what Eve's atmosphere is made of, other than the fact that it doesn't have oxygen. Eve is the game's analog of Venus, and IRL Venus' atmosphere is almost entirely carbon dioxide, which you can't burn with anything.

Currently Ion engines can be made to work, but of course you need to ship xenon fuel supplies from Kerbin.

Ion engines work great in Eve orbit (plenty of sunlight to power them!) They may have been a useful surface-exploration option before 1.0. However, since 1.0, they really don't work down near the surface; their Isp is so low it's practically nonexistent there, so they get even worse fuel efficiency than a rocket, and 1/40th their already-low vacuum thrust, not to mention having difficulty getting electricity (Eve's atmosphere blocks most of the sunlight).

[fourfa]

I tripled the size of my VTO ballistic biome hopper, based on a Mammoth engine. Went from 6km range to like 10km. Not worth the trouble on Eve, though it's a pretty fun way to get around!

Still haven't gotten a plane with onboard ISRU off the ground on Eve surface.

Beefed up and simplified my 2-Kerbal rover, with 6 wheels instead of 4, pared down to the bare minimum, with struts everywhere. I've been hooning around on the surface and haven't been able to break anything except (repairable) wheels. Looks like the way to go, unless mini ISRU and possible Eve atmo update really change things.