1.0.5 Eve Return Tips

[Dfthu]

Right now i'm doing a Elcano challenge on Eve and ill have to get back somehow. I Have no idea what to do. I tried looking for 1.0.5 Eve returns but I couldn't find anything. And i apparently need about 8500 dv. How will I sheild it though reentry? How do i launch it to Eve? I need you guys to help me on this one. I really appreciate the help.

[Snark]

Eve return landers are probably the biggest challenge in the game.

General tips (other than "you'll need a lot of dV"):

You need engines with a high TWR and good atmospheric Isp, which narrows the selection a lot. Basically it comes down to Mainsail, Aerospike, Mammoth, Vector.  The Vector is particularly effective because it packs such a ridiculous amount of thrust into a narrow 1.25m form factor, which is useful in slipping through Eve's deep, thick atmosphere. Yes, it's overpriced, but on Eve it's worth it.

If you can manage to land somewhere at high elevation, you can shave a lot off the dV requirements to get back to orbit.

Be relentless about mass stinginess. Don't carry an ounce you don't need. Eve is one place that it helps a lot to do it Apollo style, i.e. leave a transfer stage in orbit, so that your lander only needs to get back to low orbit and not all the way back to Kerbin. A last-stage that works well for a lander is Mk1 lander can, 2 tons LFO, Terrier; small, light, packs a lot of dV.

You'll need a heatshield for reentry. Eve reentry is very punishing; spaceplane style entry is hard.

Launching from Kerbin takes some thought. A lander that can pack enough dV to get off Eve generally has enough oomph to SSTO from Kerbin to LKO. So I typically launch the lander by itself, without an interplanetary transfer stage, and arrive in LKO intact but mostly empty. Then I refuel it in orbit, dock an LV-N powered transfer stage to it, and depart.

Edited January 9, 2016 by Snark

[Wanderfound]

Eve ships don't have to be huge. Asparagus staging, in multiple layers. 

Try this: a small lander can on top of an FL-T200 and Twitch, with a quartet of asparagus-staged (i.e. dropping in pairs, fuel lines from droptank->droptank->core) Oscar-B drop tanks. Make the drop tanks from three or four Oscar-B's per decoupler, small nosecones on top and below. That's more than 4,000m/s ΔV right there.

Under that, a decoupler and a pair of FL-T800's on top of a Vector. Surrounding it, a quartet of asparagus-staged radial boosters, each made from a pair of FL-T800's and an Aerospike. Lightly strut where appropriate; make sure to base the struts from the outside in (to lose their mass when decoupling).

All up, that should give you sufficient Eve launch TWR and about 9,000m/s ΔV. To get it down, put decouplers and heatshields under all five launch engines. Put large parachutes on top and landing legs on the bottom of the boosters, and something aerodynamic (nosecone, parachute, shielded docking port) on top of the lander can.

Squeeze a few more ΔV out of it and you can afford to carry a Science Jr and a service bay stuffed full of science gear. Don't forget the ladders if you're planning on getting out, and stick a probe core in the service bay if you want a scientist to fly it.

Getting it to Kerbin orbit isn't hard; just don't drop the boosters, and refuel it in orbit. Getting it to Eve will require a tug; nuke if you're patient, KR-2L and/or Vector if you're not.

It's often easier to pull than to push; just be sure to disable gimbal on the tug engines and take care that the exhaust doesn't hit the cargo. Vectors or Nukes mounted on hardpoints or structural pylons are good for this.

Edited January 9, 2016 by Wanderfound

[Wanderfound]

It's just occured to me that heatshields under the engines won't work if you're using the Eve lander engines to get it to LKO.

Two options: either an extra set of boosters on the lander (to get it to LKO without using its own engines; again, use the lander fuel to power them and refuel in LKO) or a big heatshield mounted on a Klaw (launch separately, attach it to the lander in LKO).

In either case, the shield is just for descent, not aerobraking. Use the tug to put it into a nice low Eve orbit before you touch the atmosphere.

Edited January 10, 2016 by Wanderfound

[Snark]

21 minutes ago, Wanderfound said:

It's just occured to me that heatshields under the engines won't work if you're using the Eve lander engines to get it to LKO.

Two options: either an extra set of boosters on the lander (to get it to LKO without using its own engines; again, use the lander fuel to power them and refuel in LKO) or a big heatshield mounted on a Klaw (launch separately, attach it to the lander in LKO).

Or you can put the heat shield on top of the ship and enter Eve atmosphere prograde.  You can stick a nosecone on top of the shield for aero while launching from Kerbin.  Just make sure you ditch the shield on the way down, once reentry heat fades; you don't want to be lifting heatshields off Eve.

Edited January 10, 2016 by Snark

[Wanderfound]

8 hours ago, Snark said:

Or you can put the heat shield on top of the ship and enter Eve atmosphere prograde.  You can stick a nosecone on top of the shield for aero while launching from Kerbin.  Just make sure you ditch the shield on the way down, once reentry heat fades; you don't want to be lifting heatshields off Eve.

I'd be a bit worried about the structural shock on parachute deployment if you couldn't manage to get the lander spun retrograde during the descent. But that's a solvable problem...

[Nefrums]

Add lots of airbrakes and chutes, preferably attached to radial decuplers so they can be discarded before accent.

 

 

[Temstar]

One other trick: remember if you really want to shave down the mass to orbit you can use the kerbalnaut him/herself as the final stage. The EVA suit's MMU has something like 600m/s of delta-v. So it's quite acceptable to design a lander that gets the kerbalnaut to suborbital velocity 400m/s short of LEO, then bail out of the lander, taking all the science with you and use the MMU to complete climbing to orbit with 200m/s as both reserve and fuel to get into the return craft.

Edited January 22, 2016 by Temstar

[Snark]

On 1/10/2016 at 1:11 AM, Wanderfound said:

I'd be a bit worried about the structural shock on parachute deployment if you couldn't manage to get the lander spun retrograde during the descent. But that's a solvable problem...

Just now noticed this post from a couple of weeks back.

I've found that structural shock from parachute deployment is fairly straightforward to deal with on Eve.  For one thing, with 1.0, parachute deployment became much less sudden, so that alone solves a lot of problems. 

Also, Eve landers can now be a lot lighter than they used to be; the smallest I ever managed in the old, pre-1.0 souposphere days was a couple of hundred tons, and now folks manage with landers that are just a small fraction of that size.  So, less mass to slow down = less shock.

Finally:  even if there is some concern about structural shock, that's easily dealt with by simply spreading out the pain, i.e. not staging all parachutes at once.  The initial deployment can just be one or two parachutes, which will slow you down so much that subsequent parachutes have much less "jolt".

[Gojira1000]

Or just drop a Delta Heavy onto Eve. 

https://www.youtube.com/watch?v=a1528MDIGBU&index=11&list=PLtaUHjRks0DZaZnqc32FGyYCZ6efW4_Pv

In retrospect, this was a terrible idea. On the plus side, it was so sloppy I'm sure you can manage to tune it and take a rover instead of all the junk I dragged along.

And you can go a lot lighter on the return - that thing managed orbit from the beach on its first run.

[Dentarg]

On 09.01.2016 at 4:47 PM, Wanderfound said:

Eve ships don't have to be huge.

I've got a quest to bring 2000 ore from Eve... 20t payload is not the same as a lonely kerbonaut with a few sensors. Now I have 1kt lander (reaches Kerbin orbit without decoupling but still not sure if dV is enough), 3.5kt tanker (will need two trips) and also have to invent a transfer stage. This is hell.

Spoiler

Spoiler

 

 

 

Edited February 1, 2016 by Dentarg

[fourfa]

that is the worst contract of all time

[linuxgurugamer]

Moar boosters needed

Actually, nothing says you have to do it in one go.  So why not set up a fuel manufacturing facility on Eve, and put a station in orbit, and then you can boost smaller amounts of ore up to the station.

You may want to get the ExtraPlanetry launchpads for this

[Snark]

5 hours ago, Dentarg said:

I've got a quest to bring 2000 ore from Eve...

Out of curiosity, what exactly does the contract say?  You may not have to do what you think you do. 

The "move ore from A to B" contracts don't actually require moving ore from A to B, in my experience.  Once ore is mined, ore is ore.  The game has no memory (and no ability to remember) where the ore originally come from.  So even if the contract is supposedly "move ore from Eve to Gilly", for example, typically the actual requirements are:

• mine 2000 units of fresh ore from Eve
• have 2000 units of ore on your ship
• be in GIlly's SoI

...which an astute observer will realize that you don't actually have to lift the ore from Eve.  Land a one-way ship on Eve that's never coming home.  Mine 2000 units of ore and leave it on Eve.  Launch a different ship which goes to Gilly and mines 2000 ore there... or launch a ship from Kerbin that already has 2000 units of ore in it when you launch, and fly it to Gilly.  Either way:  contract completes.

Of course, if you like this contract just for the sheer challenge of it, by all means go ahead.    Just sayin' that you probably don't have to if you don't want to.

Edited February 1, 2016 by Snark

[LunaTrick]

On 1/9/2016 at 5:23 AM, Snark said:

"You'll need a heatshield for reentry. Eve reentry is very punishing; spaceplane style entry is hard."

I didn't need any extra parts for the heat and I landed a massive rover to find the highest peak.

Just keep your speed down to 800-950m/s and live through the upper one third of the atmosphere and you'll do just fine. Almost feels like I've cheated the game.

[Snark]

38 minutes ago, LunaTrick said:

Just keep your speed down to 800-950m/s and live through the upper one third of the atmosphere and you'll do just fine. Almost feels like I've cheated the game.

...and how did you get your speed down to 800-950 m/s?  How fast were you going when you hit atmosphere?

[LunaTrick]

I use the same method I use at Tylo to land. Altitudes are a bit different, but otherwise exactly the same.

I figure out where I want to land. Eve's vacuum starts at 90k so I put my PE at 90-95k over the area of the landing site. Then set a maneuver node at the PE and use retrograde until you have a bell curve and the leading blue line is adjusted in time to be on the landing site.

 

The speed is what kills. You have two components of your speed. What we are doing here is almost completely negating our horizontal velocity leaving only the vertical velocity to deal with.

 

My engines run at 20 - 30% throughout most of the upper third of the atmosphere. They never burn up and neither does anything else. Once the red flames disappear just turn off your engines. You won't need them again until about 100m (assuming your brought parachutes with you).

[Plusck]

On 31/01/2016 at 6:25 PM, Dentarg said:

I've got a quest to bring 2000 ore from Eve... 20t payload is not the same as a lonely kerbonaut with a few sensors. Now I have 1kt lander (reaches Kerbin orbit without decoupling but still not sure if dV is enough), 3.5kt tanker (will need two trips) and also have to invent a transfer stage. This is hell.

I had one of those. 2350 ore it was.

I tried, valiantly, to do what the contract said. Then I abandoned the idea. The contract said to mine 2350 ore on Eve, have 2350 ore on my ship, and bring it to Gilly. So I brought an empty couple of ore tanks from Kerbin, picked up ore from an asteroid I had brought into orbit around Eve, and took that to Gilly instead.  I think I could probably have just mined it on Gilly, but I thought I'd at least pretend it was fresh Eve ore

 

And for the mining ore, you don't have to mine it all at once either. The miner I finally sent down there only had a small ore tank. It was a bit boring waiting for it to finish mining without an engineer, and jettisoning the ore every so often, but I wanted a slimline lander to get through the atmosphere without massive heatshields.

[fourfa]

The new 10m heatshield in 1.1 should at least make landing a proper ISRU rig simpler...

[Broco]

Boy, Eve was really one of the toughest challenges I did, needed 3 tries to make it. My final workingdesign was basically an asperagus staged lander with a return craft I left in orbit. I also put detachable drills and ISRU-Units on it to harvest some fuel:

In the end it was still WAY too close for comfort, I should have dropped those chutes.

But generally I have to agree, Vector + Aerospikes are your best bet. But remember, in Eve atmosphere an Aerospike can not lift as much as of Kerbin. Plan accordingly.

[OhioBob]

14 hours ago, Broco said:

But generally I have to agree, Vector + Aerospikes are your best bet. But remember, in Eve atmosphere an Aerospike can not lift as much as of Kerbin. Plan accordingly.

If you don't mind using modded engines, the following helps:

Eve Optimized Engines