[SOLVED] Returning from EVE (6 months trying...)

[extremez3r0]

Sorry if this is not the right board for this post. I'm new here and by all that I see is the best place to post it...

Guys, I'm at a step of give up this mission...

My 3 astronauts are in EVE for 49 years! I'm trying to rescue they since about August. I've wasted more than 110 hours in this ....ing mission, but I just CAN'T!!!

I've read all tutorials "Returning from EVE", "Eve Atmosphere", ..., .... but I just CAN'T!!!!

I don't want cheat, I don't want use mods... All I want is my astronauts in home alive =(

This is my ship:

I just want get this .... in an stable orbit around Eve with my 3 astronauts... just it!

I'm landed almost on equator (0º 31' 2" N, 166º 38' 26" E) at 3448m

Here is my quicksave: http://www.filedropper.com/quicksave

I have another save before land this rescue ship here, but It will need a LOOOOOOOOOOOT of work to bring astrounauts to this ship after land.

If someone will try, be carefull. Fist booster stage has a bit less fuel in one side than other side. Release fist booster stage 1 second before use all fuel to avoid ship lost control.

Sorry for bad english. I'm practicing.

Please help me guys... thanks a lot!

Edited December 25, 2014 by extremez3r0

[bigyihsuan]

I've actually never returned from Eve, but there are a few things that you can modify with that lander, like getting rid of the landing gear after you launch.

You need as much TWR as you can when returning from Eve.

Another tip is to have the lander be separate from a transfer stage so that you can actually return.

[NecroBones]

Just from the screenshot, it looks like the lander is in the right sort of size-class. But there are some things to consider--

* What engines did you put on it? Usually the toroidal aerospikes are a great choice here, since they don't lose much efficiency in thick atmosphere, and have pretty good thrust.

* Sometimes building wider is better than taller here (particularly if you're not using NEAR/FAR, but rather the stock aerodynamics). It looks like your stacks are pretty tall, so the TWR probably isn't fantastic, but that's OK in the earlier part of the flight since the atmosphere is so thick.

* If you use an ejectable engine/tank for the de-orbit burn, and parachutes for the landing, you can land with all of your tanks full.

* It looks like you have an asparagus setup (as far as I can see). That's very good here.

* If you build both the parachutes and landing legs onto girders and other parts that are on radial decouplers, you can use all of that for landing, and discard it at lift-off. So the added weight of all of those parts are essentially "free".

* When launching, the flight profile here should be a little different than on Kerbin (with stock aero, anyway). You'll want to go straight up for much longer, and not start the gravity turn until 30-35k altitude. Even then, pitch over gradually.

* Landing at 3400+ altitude is pretty decent. It gets a lot harder below 2km. At sea level it's -really- hard.

[gmpd2000]

Also, consider Eve's higher gravity, so your TWR MUST be higher than 1.7 on Kerbin, Add a little more for the souposphere.

[Jouni]

I tried the quicksave, but the ship didn't work with the changes to fuel lines and struts in 0.90. Assuming that the asparagus staging works correctly in earlier versions, the only obvious flaw in the ship is the lack of control authority. I couldn't point it straight up for the initial ascent, so I ended up wasting a lot of delta-v.

[extremez3r0]

Thank you guys,

I've already done almost all you said.

My land legs and parachutes are ejectables (i'm already ejected parachutes at this quicksave).

I'm using toroidal aerospyke and an asparagus setup.

But I'm thinking this ship is too heavy. And my TWR is lower than necessary, since it never gets close to final velocity at EVE. Ever still about a half of final velocity.

I'm think that with this ship at this quicksave (3448m) is impossibly to get into stable orbit. Probably I will need land more high (4k) or use another ship. =(

Any other tip? Thanks.

[Frank_G]

You could drop a rover and move your kerbals to higher ground. Then land the return vehicle there and try again. Eve is a real hog, when it comes to return missions. From the picture, your return vehicle looks pretty much ok.

I found it very helpful to launch straight up, beginning the gravity turn very late at arround 40 km. My capsule was powerful enough to do a circularization on its own, so all i needed to care about, was getting it out of the atmosphere. You can take a look at the link to my Eve return mission in my signature. The lander / ascend vehicle is completely stock and no aerodynamic mods were used.

[Xavven]

Could you send a .craft file that contains your lander? That way we can checks its TWR and delta-v.

[Oafman]

No technical advice to offer, beyond what has been given, but just two things to add:

1) This is the hardest thing to do in KSP. Don't get disheartened that it's taking a long time to perfect.

2) You are close. Your ascent vehicle has a lot of the right kind of attributes for a successful take off and escape. You're nearly there, so don't quit now. Think how good it will feel when you achieve it. And think of the poor kerbals...

Good luck, and keep us informed

[Frank_G]

Could you send a .craft file that contains your lander? That way we can checks its TWR and delta-v.

Delta V = 10.5 k / TWR on Eves surface 1.2 - uses 8 asparagus aerospikes and 1 skipper as last stage of the asparagus setup. I have a new version of the craft for .90. The old one no longer exists.

[Joonatan1998]

Hard to see from the picture, but having a small final stage using 48-7S could work.

[EdFred]

There's a couple Eve craft in my signature, and you can d/l the craft file. The only mod is MechJeb (though, I may have removed the MJ module before uploading.

They might give you some pointers. Oh, and they are both able to reach 100km x 100km from sea level.

[von Ziegendorf]

I see you build a rocket like in the "Returning from Eve" tutorial which I wrote a couple of versions ago. Now you should use the 48-7S engine for the upper stage instead of LV-909. And I would remove all those FL-T100 tanks. It was written that aerospike can lift only one and a half of the long tank. If you experienced serious stability problems maybe it would be better to swap aerospike boosters for the LV-T30 ones. If you'd still have problems try launching only one Kerbal at the time - they are not massless when in EVA.

[Xavven]

Delta V = 10.5 k / TWR on Eves surface 1.2 - uses 8 asparagus aerospikes and 1 skipper as last stage of the asparagus setup. I have a new version of the craft for .90. The old one no longer exists.

That TWR might be too low. I'll try out that save when I get home. I remember that on my first Eve return lander I underestimated atmospheric drag. IIRC I was more comfortable with 22-25 m/s^2 of acceleration at the beginning of each stage, which is closer to 1.3-1.5 Eve TWR.

[X-SR71]

My 3 astronauts are in EVE for 49 years!

Ah why bother? They won't even recognize their own children anymore!

[lirg03]

Don't give up! You are doing well and your lifter is on the right track. A bit attention to the details should squeeze more dV out of it.

Here is one of my Eve lifters. http://imgur.com/a/EdfgU

[NoPanShabuShabu]

Your ship is easily capable of making it off Eve if you fix a couple of things and fly it right.

The top tanks on the first two boosters that you eject have different amounts of fuel in them, which causes the ship to go out of control just before it's time to drop them. This will wind up making it do the same thing when you drop each next asparagus stage. Transfer fuel from you're bottom center tank into these to top them off before liftoff.

Fix the staging at your last two decouplers so that they go off at the proper order instead of at the same time.

Separate out the six seperatrons on the final stage into 3 stages, with 2 opposite sides going off at the same time. This will allow you to control you're final orbit, otherwise you could just wind up going into a very high orbit that reenters the atmosphere.

Flying:

Z to start the engines

Stage off your landing gear

Work to keep the ship pointing straight up

Keep going straight up until all the outside stages are done

Start tipping to East

Follow the surface prograde marker until you are 45 degrees from vertical

Stage when necessary

Keep pointing 45 degrees until your apoapsis is about 95k

Point about 10 to 20 degrees from vertical, or higher to keep your apoapsis out in front

When you have about 100k apoapsis, and have cleared the atmosphere, coast to apoapsis and burn until you have a safe orbit

Use your last six seperatrons in pairs at or near the apoapsis if necessary to get a safe orbit. And if that still isn't enough, EVA your Kerbals and jet pack to a safe orbit.

I was able to get it to orbit without using the last stage's seperatrons, still had 2.83 fuel in the tank. Even if you still haven't reached a safe orbit with the rocket engine, the seperatrons used in pairs have way more than enough punch to get you to safety.

[NoPanShabuShabu]

Also, seeing all the other stuff on the surface reminds me so much of my first Eve mission. You actually are on the verge of completing this thing! The return ship will definitely make it.

[lajoswinkler]

Maybe you'll find this to be helpful. I did it using few mods, but in the end, it's a stock behaviour and I did it for the aesthetics.

[annikk.exe]

I undertook and completed a task very similar to this back during Alpha 0.24.

The mission requirements were as follows:

1. Manned return journey to Eve

2. No stages/junk to be left in orbit anywhere

3. No refuelling

4. No docking/undocking

5. Kerbal must be able to get out and walk around on the surface of Eve.

6. Kerbal must return home alive in the same ship.

7. Stock parts only

From my experience, the hardest part of all is getting the landing stage right. I spent weeks (in real life) testing it on Kerbin to make as sure as possible that it would perform as expected upon arrival at Eve.

The asparagus was so intense during takeoff from Eve that I was advancing a stage every 1.5 seconds.

A few notes on things I learned during the experience.

You can't afford anything extra. No science, no legs, no parachutes... all of that stuff is too heavy, and will need to be detached before you begin Eve liftoff.

Also, 48-7S is the only viable engine imho. Toroidal Aerospike is too heavy. TWR is king here.

With so much fuel and complexity, the landing is very dangerous, so I used a huge number of parachutes.

The design is like this:

Fuel Tank > Cube > Decoupler > XL Parachute > Cube > Drogue Parachute > Sepatrons

The drogue chutes deploy first, then the XL chutes... this is to slow the craft down more gently during descent, to prevent damage.

Once landed, the decouplers and sepatrons fire and the parachutes are detached and thrown safely away from the craft.

The landing legs are also on decouplers, fired during liftoff from Eve at the same time as the engines. The weight of the legs is more than zero, so they have to go.

The whole thing was about 70 stages in total. Enough for a single Kerbal in a Mark 1 pod to go to Eve, then go home. I didn't take any science modules or anything else whatsoever - the only "payload" was the pod with 1 kerbal inside. I made it home with a very small amount of fuel to spare in my final fuel tank. Getting 3 Kerbals home would not have been possible with my design, it would require a much bigger rocket or breaking the docking or refuelling rules. Or three seperate journeys.

Hope that this gives you some ideas to optimize your rocket. Good luck. :>

Edited December 23, 2014 by annikk.exe

[cicatrix]

Guys, suddenly I have a question to ask - do Kerbals have mass? Is there a difference whether 1 or 3 Kerbals are onboard?

[annikk.exe]

I believe Kerbals have a mass of 0.05 tons, however I'm not sure if they still have that mass when onboard a vessel.

The main difference is that you would need to take a heavier pod than the mk1 pod. In fact, you'd be at least double the payload weight.

[NecroBones]

In case it's useful to see more examples of missions that worked, here was my more successful visit:

Javascript is disabled. View full album

[lajoswinkler]

A Kerbal, with its EVA suit, has 0.09 t. That means 90 kg. That can be easily checked in the map view.

Onboard a vessel, their mass is 0. Strapped to those EVA chairs, they remain at 90 kg.

[Vaporo]

Tons of good Eve attempts in this thread:

http://forum.kerbalspaceprogram.com/threads/95642-The-Eve-Rocks-Challenge