Eve landing and return in 1.0

[Tiaga]

So I got a contract in my career mode to plant a flag on eve. So I decided to fire up the sandbox game and start designing and testing a eve lander. Haven't seen anyone else post a return mission from eve so I thought I would post my mission to "help" others. Although I'm sure there are better way to do things.

My final rocket cost was $9.6 million and the mission contract offered $652K. I'm not sure if its possible to make money on this contract? And if it is I would think you would have to land on the highest eve mountain which means a ton of reloading for all the failures. I wanted to make a craft that could at least launch from 1000m so where I landed wasn't a big deal as long as I landed in one piece. Also once I had the eve landing and interplanetary stages designed I pretty much started strapping on engines and fuel tanks to get off of kerbin. Which could have been done better and saved some money.

When 1.0 was coming out I was worried that this mission would be too easy compared to .90. Boy was I wrong! Arguably it is easier to launch off of eve but the extra delta v required to land and get into eve orbit makes it overall more difficult (see lessons learned below).

Lessons learned:

-Drag is Huge! And it doesn't work like you would expect. For instance, I built a rocket that would get into eve orbit...Then I added ladders for my kerbal and it would no longer get into orbit. Things like struts as talked about in other threads also cause more drag than expected (IMO).

-Aero braking to get into orbit like in .90 doesn't seem to be viable unless you have a very small craft. Which means packing on alot more delta v to get into orbit at eve.

-Its difficult to land without your ladders exploding due to heat. Which means deorbiting with a lot of delta V to get your speed down. I used a lot of air brakes to help with this. They seem to be pretty helpful.

-Drogue parachutes are helpful here. They don't rip your aircraft into pieces when trying to land and keep your craft pointing the right direction when trying to land.

-In .90 i used to shoot for 1.4 TWR to get off of EVE. With the limited testing I did being around 2.0 is much better. I was seeing mach effects and re-entry effects until about 32,000m during my launch.

Below is the pictures from the mission. I forgot to put a second kerbal in the 2nd capsule and I used hyperedit to get the 2nd kerbal to my spacecraft (Doh!). So now is the time to call me a cheating *. Also I used kerbal engineer and KW rocketry (maybe some B9) addons.

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http://imgur.com/a/0rora

Edited May 24, 2015 by Tiaga

[Frank_G]

Pretty impressive craft. Congratulations, Sir.

[KarateF22]

I gotta ask, how many tons was that on the launchpad and on Eve's surface?

[Tiaga]

I gotta ask, how many tons was that on the launchpad and on Eve's surface?

Weight at kerbin is 17,732 tons.

At Eve landing weight is approximately 444 tons (is less than that since alot of fuel is gone to deorbit and land).

Weight immediately after lift off is 164 tons.

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[selfish_meme]

Next time put a lander can on the bottom so you can transfer internally, no ladders. You leave it on Eve to save weight.

[Foxster]

...and KW rocketry (maybe some B9) addons.

Ah, you lost me at that point .

I went about it slightly differently. Instead of dropping all that fuel to the surface I landed my ship nearly empty and took along a detachable mining setup. Made the craft smaller, atmosphere entry easier and I got away with just 4 air brakes and a bunch of 'chutes.

[Tiaga]

Next time put a lander can on the bottom so you can transfer internally, no ladders. You leave it on Eve to save weight.

How do you do this? I didn't know you could.

Ah, you lost me at that point

I did use all the stock engines if that helps. Your craft looks cool. How low an altitude can you take off with it?

[Red Iron Crown]

That...is a lot of nukes. I wonder if a single Rhino instead would have made the transfer stage lighter or heavier?

[cicatrix]

How do you do this? I didn't know you could.

I did use all the stock engines if that helps. Your craft looks cool. How low an altitude can you take off with it?

Suppose you have 2 cans (1 occupied on the top and 1 empty on the bottom). Click the hatch of the top one and in a popup window click transfer. Both cans will become highlighted. Click the bottom one. Congrats, now the pilot sits in the bottom one.

Even before this option was introduced you could always go EVA wile on the orbit and then move your pilot to the other cabin.

[selfish_meme]

I tried making a copy of Foxsters but was curious about the first stage core. I figure it must be a mainsail but it looks as short as a poodle. The poodle has more delta-v but the TWR is too low to lift it by itself. Anyway I tried it had a maximum of 9000ms delta-v, so a near sea level launch should be possible.

[Unfawkable]

This looks massive. It's quite a feat, but somehow I think it could have been done more elegantly if you constructed it orbitally instead of lifting that whole monster into Orbit. Nevertheless great job, I still didn't find the courage to try an Eve landing in any version let alone this one.

Edited May 26, 2015 by technicalfool
Laaanguage!

[Hotaru]

Impressive! Especially doing it in one shot. I've never even seriously contemplated a manned Eve surface expedition, I'm still working my way up to Duna. Not bothered by the non-stock parts personally, I almost never play a fully stock game and KW and B9 are two of the best mods out there in my opinion, both fill in a lot of major stock gaps.

[Foxster]

I tried making a copy of Foxsters but was curious about the first stage core. I figure it must be a mainsail but it looks as short as a poodle. The poodle has more delta-v but the TWR is too low to lift it by itself. Anyway I tried it had a maximum of 9000ms delta-v, so a near sea level launch should be possible.

Yup, its just clipped up a bit to give some ground clearance. It can lift from sea level no problem but you have to get well up out of the soup before turning.

[Tiaga]

This looks massive. It's quite a feat, but somehow I think it could have been done more elegantly if you constructed it orbitally instead of lifting that whole monster into Orbit. Nevertheless great job, I still didn't find the courage to try an Eve landing in any version let alone this one.

I never really liked doing the orbital construction. Frame rates seem to be 10 times worse when flying next to large ships and it is a bit more work. The ship is pretty ugly except for the launcher and the pics with all of those air brakes out while landing look pretty good.

[Unfawkable]

I never really liked doing the orbital construction. Frame rates seem to be 10 times worse when flying next to large ships and it is a bit more work. The ship is pretty ugly except for the launcher and the pics with all of those air brakes out while landing look pretty good.

Meh, function over form :-)

[SkyRender]

Good grief... I'm guessing you didn't want to refuel in orbit, with a behemoth like that! Still, well done.

[selfish_meme]

My version of Foxsters Eve Return Vehicle, 104t, 8500ms Delta-v, it might need some work, it has an initial twr of 1.7 my tests so far indicate 1.6 is the minimum for takeoff, I am still testing it.

[KerikBalm]

Why do you only use drogue chutes? SHouldn't you use some main chutes so you use less fuel to land?

Also? No nosecones for drag reduction?

I don't see why you can't aerobrake at Eve arrival... you should only need to bleed off a little speed to caputure, then multiple passes can lower your craft down.

Was your landing stage completely out of fuel? it seems to me you left a lot of rockets and tanks just sitting on the surface.

It also seems to me that your ascent craft could be lighter... did you really need a 1.25m reaction wheel under your pod?

What was that decoupler for?

[selfish_meme]

One thing I thought of, shouldn't the thrust be lower on Eve, if the thrust of a mainsail is say 320 at one Kerbin atmosphere it would be much less at 4 atmospheres. Does the games reduce thrust as atmosphere goes above 1 or is it a one way scale?

[Foxster]

My version of Foxsters Eve Return Vehicle, 104t, 8500ms Delta-v, it might need some work, it has an initial twr of 1.7 my tests so far indicate 1.6 is the minimum for takeoff, I am still testing it.

http://i.imgur.com/kZAsJJ6.png

Have you tried this yet? I'd be interested to see how just two engines in the first stage cope. When I was playing with it, I found that I needed a high TWR punch at launch or the craft ran out of steam quickly. I don't know the rationale behind that, it just worked, whereas an apparently more efficient, in TWR terms, craft would not make orbit.

Edited May 27, 2015 by Foxster

[selfish_meme]

No, i will hyper edit it later, a 1.6 twr craft just hovered though

[selfish_meme]

Actually had a staging error, initial twr was 2.57, and you do need a twr over 2 to get going.

[Tiaga]

Why do you only use drogue chutes? SHouldn't you use some main chutes so you use less fuel to land?

Also? No nosecones for drag reduction?

I don't see why you can't aerobrake at Eve arrival... you should only need to bleed off a little speed to caputure, then multiple passes can lower your craft down.

Was your landing stage completely out of fuel? it seems to me you left a lot of rockets and tanks just sitting on the surface.

It also seems to me that your ascent craft could be lighter... did you really need a 1.25m reaction wheel under your pod?

What was that decoupler for?

I only used chutes at all because my ship would land head first. And I only used around 500 delta V to land so its not really worth the hassle of trying to get normal parachutes from ripping your ship apart.

I had nosecones for the actually launcher. Nosecones don't help for landing.

I've tried aerobraking other craft and stuff starts exploding pretty quickly (ladders especially). I don't see how it could be done unless you are using a small ship.

Ya, I probably didn't need the reaction wheel. Originally I wasn't going to use fins but was too difficult to not use them. The last decoupler was to ditch the tank and engine for the return trip.

[KerikBalm]

500 dv is quite a bit... I'd think with the droguq already deployed, that some standard chutes could save you another few hundred m/s.

Then you can use that for the ascent.

Again, why didn't your "base"/"launch platform" use its remaining fuel to get a biit of a start for the ascent craft?

The nose cones may not help landing... but you had to lift them up from kerbin, where they would be useful (and you can't fit that thing in an aeroshell)

[selfish_meme]

Nosecones are a must on Eve. Mach effects start at just above 100ms a second, even an exposed mk1 command pod has enough drag to flip a rocket.

- - - Updated - - -

Have you tried this yet? I'd be interested to see how just two engines in the first stage cope. When I was playing with it, I found that I needed a high TWR punch at launch or the craft ran out of steam quickly. I don't know the rationale behind that, it just worked, whereas an apparently more efficient, in TWR terms, craft would not make orbit.

I found out nosecones are a must, it seems to have sufficient twr to get up to mach speeds. Have not had a completely successful launch yet. Still tweaking, but I think it will get close.