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Getting back from Eve?


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Since Eve has buckets of atmosphere, would initial jet/turbo/ram lifters be useful (especially since you only need LF, rather than LF/O, lower wieght) along with their high atmospheric ISP?

You could essentially build something like the LLRV/LLTV which has just a command seat returning to orbit with initial thrust via jet engines, and rockets taking over later once you're out of that dense soup

I'd try it myself to check, but the HDD in my home PC decided to pop its clogs

[Edit] Never mind, I see on the wiki that the atmosphere of Eve doesn't work for jet intakes/engines

Edited by NoMrBond
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  • 1 month later...

Eve ascent is about 11.5 km/s from sea-level, 7-8 km/s from high areas (with a bit of extra). I suggest aerospikes for the first part (although higher thrust might be necessary), and eventually switching over to the small orange engines and small tanks. 4.5 km/s (Kerbin orbit) can be done in under 6 tons (with a Kerbal on a chair), so you just need to get 6-8 tons to 15000-20000 meters. It's harder than it seems, but it can be done.

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Here's my current Eve lander:

http://cloud-2.steampowered.com/ugc/919019506139168885/D32073363809897790BEA1603D385A9FD60E6215/

It has almost 12K delta V which is enough to deorbit it and provide a bit of thrust to cushion the landing as the landing legs can't quite take the strain. It can get into orbit from sea level, (well 300m anyway), with a tiny amount of fuel to spare, (so another ship will have to rescue it from orbit). The outer stage with the big fuel tanks is non-asparagus with 4 Aerospikes on each tank while the inner stages are all Aerospike asparagus, except the very top which uses the new 20 thrust probe engine. The fins are essential to stop the thing from tipping over when the outer tanks are almost empty. No RCS as this is pretty much bare-bones. It does have ladders!

Yeah this is quite a challenge but it is do-able. Now I just have to design a 2-man version to rescue all the kerbals I trapped on Eve. Or maybe stick a control ring on it somewhere and leave the pod empty. :)

Edited by Redshift OTF
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I would suggest having wheels instead of landing legs.

That way you can simply land somewhere close to the area where the highest peak is (7540 meters above sea level) and drive your lander up the hill until you reach the top.

You then detach the wheels at liftoff. The buggy wheels works really well for this.

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Keep in mind that Eve's highest point is around 6 km rather than the 11 km that it was before. Also aerospikes have had reduced TWR.

Because of this, older designs probably won't work anymore.

My own attempt at a return trip from Eve is currently about 130 tons with a TWR of about 2.4 and delta-v of just over 10k, but I'm still trying to reduce its mass and increase its delta-v.

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MYKHfMw.jpg

uSiokLT.jpg

Still working on the launcher. I put it aside to do some other challenge.. Will get to try this soon.

I found out kerbals add weight when in the chair, this thing was 12k but lost nearly 800d/v in final stage because it was built so minimized. (see big lander leg stuffed in chair to simulate weight)

I added a pile of chutes to this but they all eject off before launch.

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  • 1 month later...

I also tried my hand at an Eve-lander... Had a few Iterations. Quite huge, all in all.

And did some tests. Getting the beast into orbit of Kerbin, Hyperedit it to Eve (will do it the "hard" way, once I know the lander can do it), descent...

And there it ends. As soon as my 'chutes grap atmosphere, they rip the thing apart.

screenshot584.png

This one shows the deployed drag chutes. Once they caught air, they shredded the vessel.

Same with this one here:

screenshot576.png

EDIT: Wups. Actually, both the same vessel, just one orbital manouver stage attached.

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I hear the smallest Eve return vehicle using ladders is now under 10 tons, that means you could easily put such a craft on top of a rover and actually drive it to the highest peak. The highest peak on the new Eve in 0.21 is now even higher, though it's further away from the equator so some inclination change may be required for docking. Still, inclination change of say 10 degrees is easy for a return craft when it means you could have a small lander.

This was the lander I used in 0.20 to return two kerbonauts back from the surface. I landed at just under 5km altitude:

screenshot1398.jpg

Here is the entire Eve stack leaving Kerbin:

screenshot1050.jpg

It was built up from 5 launches. One for the surface return craft, one for the Eve rover, one for the Gilly lander, one for mothership and one refuelling tanker run. The surface return craft was about 50 tons fully fuelled in Kerbin orbit.

Here's the mission log:

http://forum.kerbalspaceprogram.com/threads/30909-Two-men-Eve-landing-and-return-%28image-heavy%29

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I really wonder if it wouldn't be simpler to use a plane to enter/exit Eve.

It was extensively tested in the SERV challenge and no one could make it work. The theory goes by using wings to generate lift you could get away with a much lower TWR since the lift allows your spaceplane to climb very slowly at low speed. The low speed reduces your drag so that drag loses and gravity loses equal and you get optimal ascent profile. But it turns out that by climbing slowly you stay in the thicker lower atmosphere for longer and suffer more drag losses that way and the two effects cancel out. The additional complicities of a winged design (shifting CoM, the need to stage a spacecraft into a pure rocket in the upper atmosphere while still maintaining asparagus staging, landing a spaceplane with dodgy CoM on somewhere other than a runway, etc) means the vehicle is much much more challenging to design than a pure rocket. You're better off putting that effort into figuring out a system to drive your rocket up hills after landing and saving delta-V that way.

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Just finished my first successful Eve return last night. Done with my 160 ton Phalanx Mark II lander (phalanx because it looks like a wall of shields (Mark II because the first one was comically inadequate). In testing, it can land at 200 meters without rocket aid (parachutes only), and return to orbit. It could probably successfully do a sea-level landing/orbit return, but I haven't tested to confirm.

I way over-engineered my tug and return craft (Note, this was too unstable, so I had to turn off some reaction wheels, separate the return craft, and fly that by itself to eve, where I re-docked and re-fueled from the tug).

2013-09-23_0000101.jpg

The thing is a tank when it comes to landing. I've hit the surface at 6m/s on Eve, and 10m/s on Kerbin without problems.

2013-09-23_0000202.jpg

Take off from Eve. It has 7 asparagus stages (3 on outer layer, 3 inner, 1 core) with an extra stage (the smaller tanks) that provide extra TWR during early ascent. Note the two reaction wheels on the outer stage. The placement ended up being key. It's a unstable craft, and the aerospike engines don't vector, so I originally had one reaction wheel in the center core (on the second to last stage), but I couldn't re-orbit from low altitudes. Removing that wheel from the center core, and putting them on the first asparagus stage that decouples made all the difference.

2013-09-23_0000503.jpg

Outer asparagus and extra stage gone.

2013-09-23_0000604.jpg

Jeb returning to return ship.

2013-09-24_0000105.jpg

Edited by csanders
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