Eve return-trip in 0.22 *** UPDATED #3 ***

[superm18]

Hi all,

It just dawned on me, Eve is sooo much harder now...

For every update i start a new game, and i'm currently going about planting flags on all the planets and moon's. Just missing Jool and it's moon's, and Eve and Gilly.

When i design my lander's i go for all the science in one mission, like this:

Duna Lander: Like this i have five of everything + 1 extra goo-thing for balance. That is for: High Orbit, Near Orbit, Upper Atmosphere, Flying and Surface.

No-Atmosphere-Lander: Like this i have tree of everything + 1 extra goo-thing for balance. That is for: High Orbit, Near Orbit and Surface.

Now i wanna do this for Eve as well, but here's the problem:

Eve Lander - pre. 0.22

12000~ Delta-v (yes i copied another user's craft). Now adding all the science things, adds about 5000 mass units. That 5000 needs to go from the surface to orbit making it a hell of a lot harder. Everybody who tried a return-trip from Eve know that.

"Why don't you just launch from the mountain?" Yes i know, but i really wanna bring a sample, from the sea. So landing very close to the sea is a must and that forces the lander to have 12000+ Delta-v.

The lander will also have to have two command pod's, to bring both the sea and surface sample back + six of every science thing

"You could just make two lander's and launch them in the same transfer-window and have each of them land/launch", Yes, a lot smarter, but i wanna do it in one go.

The lander I've built so far is MASSIVE! and so far only gotten to around 9000-9500 Delta-v...but omg....

While i'm writing this, i think it may have turned into a challenge, rather than just a "i have this problem..."-tread...hmmm...

**** UPDATE #1 ****

Okey, so i've been hard at work with this lander and this is what i got so far: (don't mind the probecore at the very top and neither the 4 nose-cone-sensor-things, just need 2. also not gonna need 5 barometer)

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I knew i had to try something else, but it didn't work out. This was done fast and i'm sure there is a better way, but as you can see below, it spins and blows up:

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Next update: Here comes the part where i try to get this massive lander safely on the ground on Kerbin. If it works on Kerbin, it will work on Eve. It's gonna take ALOT of parachutes and landing gear.

After that i will be making a craft, to take this to Eve and back...oh boy...not to mention getting the whole thing to LKO. I figure i have to get the lander and the transfer-craft up together, so that it will be strutted together.

**** UPDATE #2 ****

AARRRRRGGGG!!! my craft file got corrupted, so i have to rebuild the entire thing!

It had reached 2164 parts and 1389 t....

Anyway, i managed to get enough parachutes on to make a safe decent speed of 7.2 m/s on kerbin and the gravety on Eve is 2,31 times Kerbin's, it should get the lander down to around 3,11 m/s.

The next problem was touching down safely with enough landing-legs to support the weight. I did some testing and 6 LT-2 Landing Strut's, can safely hold 24 t. So that makes it a total of 347 landing-legs * Eve's added gravity = 802 LT-2 Landing Strut's. OMG! That will certainly bring down the Delta-v...

Then i realized that the Small Gear Bay would be much better they don't give way to the wight as much and has an impact tolerance of 50!

Anyways i have to rebuild the lander and i'm not up for it right now, so until i get back on my feet this project is on hold...

**** UPDATE #3 ****

After some cursing #*¤ i got back in.

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Now i need to add the parachute's and then start building the craft that's gonna take the whole thing to Eve, plus a small lander for Gilly.

Edited October 31, 2013 by superm18

[fatfluffycat]

Do you really need science? The tech tree is only 10,500 science(about) to unlock.......

[superm18]

yes i know i got it maxed out already but i'm a do-it-all type of guy

[Spence1012]

Holy crap.

I pulled off an Eve return but I launched from the highest mountain on Eve at like 7km+ above sea level in .21 that needed about 75% of the delta v. This is ridiculous.

You gain a lot of delta v by losing mass in the final stage. Start there, if possible, or remove stuff if if you don't ABSOLUTELY need it.

Also, attaching your parachutes and landing legs to decouplers (with struts everywhere to hold them down!) will allow you to ditch them on take off, saving some delta v.

You might even want to rethink the lander and have a Kerbal on an external seat attached to a probe body with an inline reaction wheel part underneath that. All of that is still less mass than a 1 man lander can by around half a ton. It should let you get a lot more out of the final stage. You could also shoot for a smaller lander using the little 30 kN rockets. I think it's the Rockomax 48-7s. You can attach multiple of those on each fuel tank via those little cubic structural pieces, if you need the extra thrust. They're pretty efficient and only weigh .1 ton each, compared to something like 1.5 tons for an Aerospike. So, you can save a ton or thereabouts if you can find a way to strap 6 of those little rockets onto the same fuel tank. I did a similar thing but with 3 of them for a small Minmus transfer stage on a little 1 man lander.

However, I can't see the top of your rocket so I don't know the whole design. Post another picture of the very top please!

I would say get the Hooligan labs balloon mod, but your sig says you play stock and hate mods... Sorry to say you might go insane with this one! I don't recall anyone that's returned from sea level in the short time I've been lurking here/interested in this game.

But, if I were you, I'd get the Kerbal engineer plugin. It allows you to view stats like delta v and TWR in the VAB, and nothing else really. I don't think that counts as a mod. To me, it's just helping me make use of information more easily. It will let you see whether your craft will even take off on Eve for certain, as well as how a certain part swap or removal will affect delta v. You'd be surprised at how much a little mass reduction changes things! However, that's your call as to whether that would count as a mod/deviation from stock. Doing this totally stock is a better achievement, no doubt.

Anyways, I'd love to see if you can make it!

Edited October 26, 2013 by Spence1012

[superm18]

This was the lander in 0.21:

[Spence1012]

Ok, that's basically the same idea I had with the design.

As I mentioned, it would be nice to put all of the parachutes and landing legs on decouplers so you can ditch them on launch. Those parachutes add up quickly. I wouldn't be surprised if you had several tons in chutes on that craft. Although the delta v savings won't be huge since they're on an outer stage, it will help your TWR, allowing you to bring a a little bit more fuel and get out of the atmosphere a bit quicker (just don't overdo it and waste fuel by pushing too hard against the atmosphere!) Also, I think you could lose the SAS modules or at least go down to 2 of them by placing them individually. Although they're very convenient, it's extra weight! I think the 6 of them will add up to about 1 ton combined. Just use the capsule's torque for that design plus the possible 2 units if you want the extra torque.

However, to get back from sea level with a reasonably sized rocket, I think you just have to do what I mentioned and use a probe core as the center of the craft, a seat for the Kerbal to sit in, and an SAS module to provide torque because the probe core has very low torque. You save about .5 tons with that. You could even use a Clamp O Tron Jr instead of the regular one to save that little extra bit of mass that would actually make some sort of difference in the final stage. You will at least gain something with .03 tons in savings, since the final stage only weighs a couple tons. As tiny as these revisions sound, it's things like these that you have to do to keep the size reasonable.

Other than that, I'm without much more to offer as advice. I think we need someone else with a new approach to this. Successful Eve sea level return crafts are not commonly found/built.

EDIT: Just noticed your edit. I hope you can make this happen once you're up to it! This is a tedious design process.

Edited October 30, 2013 by Spence1012

[Col_Jessep]

If put the parachutes on decouplers you probably want to secure them with struts. Trust me, learned that the hard way...

[Spence1012]

If put the parachutes on decouplers you probably want to secure them with struts. Trust me, learned that the hard way...

That is indeed true. I thought I mentioned that but I probably forgot

That could end really bad without struts.

Also, I fiddled around with designs, and I got one with 11k m/s of delta V and it only weighs about 35 tons (give or take, very approximate conversion in my head.. lol)

It doesn't have any fancy science stuff (that stuff should be added on outer stages to minimize delta v loss) you need but it's a start! It's a Kerbal on a seat, a probe core, some batteries, an SAS module for torque, some solar panels, and the rocket. It's not strutted down and doesn't have any landing legs or chutes but the actual rocket leaving the surface should be something like this with a bunch of decouplers to get rid of landing legs + chutes.

Each of the outer tanks has 4 of the little 48-7s engines attached to cubic struts. They're really light and are awesome I think. They weigh much less than an aerospike. However, for the center large tank, there's only 3 of those engines.

Also, ladders and stuff need to be added, but they shouldn't add much weight.

EDIT: I played around with adding some aerospike boosters on the outside for lols, and look what I managed This should be plenty to return from Eve at sea level.

The different looking fuel tanks are the Novapunch 6m long 1.25m tanks. They have the same fuel to weight ratio as stock tanks, I believe. This tank's equivalent could be accomplished with a couple of stock tanks easily.

Also, those TWR ratios are for Kerbin. All of the TWR ratios are above 1.24 for the main lifting stages that have to deal with the thickest atmosphere. However, this design with MOAR BOOSTERS will need a behemoth (well, compared to what you need for the first one) rocket to get it there fully fueled. The lander is 85 tons, not counting landing legs, chutes, and science equipment, which mostly won't be present after lifting off, but will still need to be brought there (duh)

Hope this gives you some ideas

Edited October 30, 2013 by Spence1012

[superm18]

By Spence1012: put all of the parachutes and landing legs on decouplers so you can ditch them on launch. Those parachutes add up quickly. I wouldn't be surprised if you had several tons in chutes on that craft

The gains, as you say, will be small and the fact that the craft has well over 2000 part's make it less desirable to and all those extra decoupler's and strut's.

I have redesigned the lander. Small dockingport and removed the ASAS.

I'm not gonna use the "seat-strategy" because i wanna use the crew report option and have all 5 EVA report's.

A side note to the parachute's, i've found that putting all the chute's on the outer ring make the craft cave in when they deploy, even with the droug-chute's, getting the speed down to around 45 m/s.

Also, those small 48-7s engine's just ain't gonna cut it. It's 1200-1400 t they have to lift. simply not enough thrust.

[Spence1012]

Ok! Sounds like a very Kerbal way of doing things!

And yes, I know that the gains from the decouplers would be small because they're on the outer stages, but it's something and is better than adding more fuel/engines if you're a bit short. Yes, in this case it wouldn't work due to the absurd part count. Also, I didn't know you were gonna a rocket design like this. This design is ridiculously large but there's no reason it can't work! I love insane designs but I won't be able to go truly over the top myself until this game can use multiple CPU cores.

Also, those little engines would indeed have to be used in stupidly large amounts to lift that, shooting your part count through the roof, assuming you can cram that many on.

The fact that you wanted that whole science-y thing on the top just didn't click with me. I believe I wasn't posting designs relevant to you. Sorry about that if that's the case.

[superm18]

Nothing to be sorry about it's always good to see another approach to a mission.

The way you build with those engine's is perfect! decent thrust and good Delta-v