Tips for a manned mission to Eve

[Fierce Wolf]

Hello guys, I'm planning a manned mission to Eve and i'm not sure how to proceed. So far I landed simple probes with shieldings and a not-that-bad rover, but all of those where one way trips. Any tips?

My flight plan:

1) Big ass rocket to kerbin orbit

2) Space taxi from and to Eve

3) Some sort of decend-capable contraption that doesnt end up in a fireball

4) A science rover

5) A big question, how do I go up from Eve in a ship that is not an uncarriable gargantuan monster?

6) A reentry ship to kerbin.

7) Champagne and a party at the KSC with friends over

 

[Zhetaan]

Without a more detailed mission plan, I'm limited in what I can tell you, but the standard Eve return advice is this:  don't launch to Eve orbit with anything more than you absolutely need to reach Eve orbit, and minimise your drag beyond all rational effort.

I would choose to land the rover separately simply to avoid complicating the return vehicle, but you can do it all at once provided that you jettison any cradles or other attachment assemblages.

It is quite popular to land on Eve's tallest mountain and return from there because the drag savings are significant, but sea-level launches are also popular as an especially difficult challenge.

To land, I suggest that you bring your vessel to circular Eve orbit just above the atmosphere and descend from there.  You probably already know that Eve's atmosphere is not kind to entering vehicles, but because you want yours to take off again, it will be especially tricky to get through the heat.

Eve return is monumentally difficult, so don't be afraid to design, test, redesign, and retest repeatedly until you have a workable idea.  You may want to make use of sandbox mode for that; since you imply an interest in returning your Kerbal, I assume that you'd rather not need to send a rescue mission after making a mistake.

Also be certain to look at the Mission Reports, Tutorials, and Challenges sub-fora.  Grand Tour missions are a good source of information in addition to the more straightforward Eve return missions.

Good luck!

[Signo]

You can build a lander/ascender that can make to low Eve orbit from sea level that weights something around 40/60t. That is of course for a single lucky kerbal. I usually drop the manned rovers from a kind of orbiting mothership and they are of course made just for landings. I made bigger contraptions to bring more kerbals but I never designed a ladder long enough to bring the famed "Eve rocks" on top of that, so I usually "cheat" with a pod placed at the bottom of the lander and I transfer the crew down there to disembark.

I am at the moment trying to design a manned rover with folding robotic arms that could work as a copter/paddleboat too but it is just an idea I am toying with since a couple of days. Really far from field deployment.

 

Lately I have seen many "planes" trying to exploit the thick atmo, looks like a good strategy but I never tried one myself.

IMO the best engines are mammoths, vectors and aerospikes. I do not have enough experience about the "new" engines". To me the Vector is still "the new one".

 

Try to minimize dead weight: if your engines can all be used for take off just do it. I usually just have the pod and the second stage engine as dead weight.

Leave any leg/chute/extra pod on the surface.

The "mothership" you should bring can conveniently host your "return ship" and its core can be designed as the core of a space station you can leave maybe in Gilly's orbit if you want to bring anything to set up some mining operation too.

 

Good luck.

 

EDIT: This stuff is old and it is not built following all the "rules" I follow now but it should still do the trick and it was pretty easy to handle. I used just a 3.75 heatshield while reentering.

I used to bring a "rover-in-a-box" there too.

The mining equipment you see was supposed to be "single use", to refill the ascender/lander that I emptied to save on weight.

Edited September 20, 2019 by Signo
Pic

[VoidSquid]

I truly wish I'd be better at building stuff, unfortunately all the stuff I create is pretty bland and uninspired  

When I stared to think about an Eve landing (I did read a lot in the forum), my first idea was to check out KerbalX for a craft to download and see how it works, what it needs for an Eve landing. Didn't find anything suitable, unfortunately.

Knowing the base numbers, I did built my own ugly contraption:

That thingy brings a mod 2-Kerbal pod into Eve orbit which then can descend:

Things to note: I rotated the top 10m heat shield 180 degrees for proper aerodynamics.

 

Landed:

Things to note:

Lots of parachutes to save fuel for the final meters before touch down. At the end of the girder segments there are solar panels. Ladders from pod to ground (EVA RCS on Eve is useless due to high gravity).

 

Ascending: immediately after firing the engines, get rid of any possible dead weight:

Things to note: Asparagus staging. Combination of high thrust vector engines and almost-constant-ISP Aerospikes. Tilted nosecones to allow proper separation (I tried separatrons, totally useless).

And all that effort to get this tiny thing back into Eve orbit:

Crew of two Kerbals will then be picked up by a taxi vessel and brought back to Kerbin.

Ugly? Definitely!

Does it work? Yes  

That 2-Kerbal mod pod is this one: https://forum.kerbalspaceprogram.com/index.php?/topic/155013-121-131-145-151-161-17-k2-command-pod-two-kerbal-stock-alike-pod/

I started using it way before MH came out, and still love to have it

 

So yes, that's it about my ugly uninspired Eve lander, don't know if it will help you, but it does the job  

 

Edited September 23, 2019 by VoidSquid

[Grogs]

Start with the lander design. Design a ship that can de-orbit, land safely, and reach orbit again. I would try to design a 1-kerbal lander initially. I tried a 3-kerbal design several times and found it to be monumentally more difficult in comparison. What the others say about minimizing drag and mass on ascent is absolutely true. Even something small like a ladder can cost you 100 m/s and make your ship fail to reach orbit. Put chutes, landing legs, ladders, and anything else that sticks out on decouplers and have them detach when you light the first stage of the ascent vehicle. Use the ALT-F12 menu to test your design and see how spectacularly it fails. Go back to the VAB and try again until you have something that works reliably.

Once you have a good lander design, you've conquered probably 90% of the major hurdles on the mission and the rest is much easier. The next piece is to figure out what you want to get the crew back to Kerbin orbit with. It may be the upper stage of the Eve ascent vehicle that refuels in orbit or something else that you bring along. Add enough fuel to get you back to Kerbin orbit.

With the mass of the lander and the return vehicle, then it's pretty simple to figure out how big of a transfer stage you need to move everything from Kerbin to Eve.

And once you have that, figure out how to get it all to orbit. Depending on how big or fragile the whole package is, you might want to break it into multiple pieces and assemble it in orbit. That makes the launches easier, but then means you have to design each piece so that it can maneuver and dock.

[Fierce Wolf]

UPDATE: So i tried an Eve mission

 

Everything went alright until it stopped being alright, namely in the atmosphere entry. I reloaded about 12 times but it was useless, at 45000 m or so the ship tips around, heats up at some 2800 m/s and explodes. My design is a long ship with lots of RCS on the capsule, and an inflatable shield at the bottom near the center of mass.

                     <=======)

<R=====<=======))

                     <=======)

R: RCS

)): inflatable shield

 

My guess was that putting RCS on the lightest point would suffice to keep pointing the shild on front, but did not.

My next try: a super 5- inflatable shield, doble de RCS.

If it doesn't work: replace RCS with a "crown of rockets" in the capsule to pack a punch in my steering needs.

If that doesn't work:

Spoiler

make an inflatable space monster that will devour us all

 

[VoidSquid]

Imo, RCS is pretty useless during atmospheric reentry/flight, the aerodynamic forces are way greater than any RCS thrust.

If you check the second picture from my previous post here, you see that I'm using two 10m heat shields, the lower one protects from the heat, the upper one provides aerodynamic stability. 

[Signo]

You need something draggy to deploy at the back to keep your attitude while reentering.

[Fierce Wolf]

I will put an inflatable draggy thingy on top as you guys suggested and post results!

[Fierce Wolf]

IT WORKED!!!

 

The infatable shield on the top worked wonders!! Thanks!!

[VoidSquid]

Congrats, happy to hear!  

[Fierce Wolf]

I DID IT (with mods, mind you)

 

I finally returned with my dudes to Kerbin and everyone survived!

It was not uneventful. What happened and what I learned (for future generations)

1) Bring 50% more parachutes than you expect. I was going down at 7.5 m/s in the midlands of Eve, surface was 1100 m above water level, and the legs kept exploding. I had to burn just to avoid oblivion and even then 1 of the legs died. So...

2) Bring DOUBLE landing legs. They can be stressed quickily with the uneven terrain, and it's not like you can chose where you land on Eve. Eve choses for you.

3) Your rover needs BIG WHEELS, BIG BATTERIES AND BIG ENERGY GENERATION. My minimalist rover went OK down the steppe, but when going back to the ship I couldn't go past 4 m/s. And if I used time warp the physics liked to do unspeakable things to the wheels, leaving them broken.

4) Things will go BOOM every minute or so. Flags explode, discarted chutes explode, that tissue you dropped on the floor explode. Check everything is still in their places before saving.

5) The ascent is HARD. I retried like 10 times before doing it right. Sometimes empty tanks impacted the ship, others it flipped losing altitude very fast, others friction incinerated the tip of the capsule. Try to go straigth up until 60km or so, then gravity turn. If your engines push too hard you will overheat, keep an eye on TWR, don't go over 3.5.

6) My space taxi had very limited fuel for the return, so an engineer had to EVA (using the KIS mod) and detach superflous mass (batteries, chutes, spent monopropellant tanks, etc). Bring 20% more Dv than you expect. It was even supposed to keep the return capsule inside a cargo with a fancy robotic arm. It worked, but I had to accomodate the capsule AND an still loaded tank, I was not going to waste 500 dv of it! (it had oxidizer, and my taxi had NERVs)

7) After a lot of planning, I burned to home using minimal Dv and aerobraked. I McGivver'd 2 remaining parachutes to the capsule so it could splash safely. It worked!

 

Thanks for the tips, I hope my experience helps

Edited September 25, 2019 by Fierce Wolf

[AHHans]

43 minutes ago, Fierce Wolf said:

Things will go BOOM every minute or so. Flags explode, discarded chutes explode, that tissue you dropped on the floor explodes.

LOL Yes. That's Eve for you.

[Freds]

A long time ago (i i'm not playing ksp actually), i managed to land and return to Eve orbit a hybrid-spaceplane. 

Karbonite engines and fuel converters to keep the plane flying and refuel as it go through eve atmosphere. After landing, science collection, etc, i returned to orbit. The return was painful: Karbonite engines to go as fast and as high as possible, MK2 Expansion Sledgehammer to go much higher and faster (almost escaping atmosphere) and finally some small engine to archive a stable orbit. It was a hybrid spaceplane because it was a spaceplane in Eve, but parts was dropped as it became useless. In the end, only the cockpit, a small docking port, a pair of Twitch engines and a fuel tank reached orbit. 

Then a tug-ship towed it to the mothership, and then returned to Kerbin. Once in kerbin, a cargo spaceplane returned the spaceplane (or, what left of it...) and the kerbals back to kerbin.

That mission was a big personal  archivement, almost a week of planning and concept testing, especially in "how to enter Eve atmosphere".
 

Edited September 25, 2019 by Freds

[Signo]

@Fierce Wolf: thank you for the chronicle, it was really fun - almost like being there.

[KerbMav]

On 9/20/2019 at 7:22 PM, VoidSquid said:

I truly wish I'd be better at building stuff, unfortunately all the stuff I create is pretty bland and uninspired  

Things to note: I rotated the top 10m heat shield 180 degrees for proper aerodynamic

Lier.

Rotating the top heat shield does not just make more sense, it even looks way better!

[Redacted]

I been working on an SSTO just for Eve...

https://kerbalx.com/Redacted/Redshift-Long-endurance-SSTO

Its a bit unorthodox but works wonders thus far. Please keep in mind that the hardest thing (IMO) is taking off as most of the lift generated is from the MK2 lifting body. Thus as such, increase your ground speed slowly (stability / air-intake are very important) and use the terrain as a ramp. Once airborne throttle up and ride just at the crafts thermal tolerance as you climb using only the ACS thrusters. (Craft will hit 1600 ms very quickly) Being that they only use electricity, you can reach 1800-2200 ms (on Kerbin) easily. Once above the thicker atmosphere, kick on both the ram-jets and stay level with the horizon for as long as your climb-rate and thermal limits allow. On a good assent profile, I’ve bested 4000 ms exiting Kerbin’s atmosphere. Which can easily launch the craft clean of Kerbin’s SoI.

Big limitation of this craft is the low TWR once in orbit so its critical that you launch directly from Kerbin close to your desired ejection angle as possible. Thus direction changes can be very time consuming if you launch in the wrong direction.

Once near Eve, start your deceleration early to come in as slow as physically possible. Before dropping in briefly to Aero-Brake and start circularization. Each time around aero braking again and again to bleed off speed till finally you can circularize using just the ion engine. Ideally, you’ll want to have your orbit just under 100km before attempting reentry.

On reentry set your crafts angle to 40 degrees so that the lifting body is doing everything possible to keep you from gaining speed as you descend. The critical part comes when your are closer to the crafts thermal limits and you need to angle forward more and more. Until, your air intakes are able to supply the ACS thrusters so that you can apply reverse thrust and drop your speed below 2000 ms before blowing up. Once you’ve gotten this far, you’ll find that the lifting body provides tons of lift in Eves thicker atmosphere allowing you to maneuver and land with a lot of finesse. Dont forget that your ACS thrusters are your best friend in an atmosphere and can help you keep orientation and allow you to actively brake when touching down.

Once on Eve, do the science thing / refuel etc... keep in mind that you may need more liquid fuel for the ram-jets, then what was needed departing Kerbin. Beyond this, manage your heat by managing your speed till you climb to a point where your ACS thrusters start to lose their effectiveness. Thus at that point turn off the ACS and engage both ram-jets till you reach exit velocity.

Edited October 19, 2019 by Redacted