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Landing on Eve and Returning Back to Kerbin


ecyenskeyn
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Hello people,

I started playing career mode  a while ago and after completing some easy peasy (Mun, Minmus etc.) missions, I have gotten stumbled by a mission that requires me to land on Eve surface and come back to Kerbin.

The thing is I feel OK with general controls and methods of interplanetary travel (I was even able to do a flyby near Eve and return back to Kerbin earlier), but after many attempts to build an adequate ship for this particular mission I failed mostly because having insufficient delta-V. I feel I have to note the most powerful tech I currently have access to;

1- RE-M3 "Mainsail" Liquid Fuel Engine

2- S1 SRB-KD25k "Kickback" Solid Fuel Booster

3- Rockomax X200-32 Fuel Tank

 

After building a 1400000 $ monstrous contraption (cannot upload image for some reason "https://imgur.com/a/Hka5y4d") and yet failing again because of insufficient delta-V, I started to consider if I was doing something wrong and looking for online material. Only videos I could find about this mission involved more powerful tech than I currently have, so I need your help.

What I need is a video tutorial or some thorough example that shows how it should be done with my current tech or similar (FOR CAREER MODE). All help is appreciated.

Thank you in advance.

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You need the vectors, mammoth, aerospike, or propellers with electric motors to do this without an unreasonable amount of pain.

 

Most engines simply lack the ISP to be at all reasonable in terms of fuel or thrust at that atmospheric density, and there is a great deal of gravity to fight.  You can try wings, but you need an engine with the highest sea level isp possible.  You can also try the top of a mountain.

This was my last sea level eve ascent (for three kerbals and a science package), although it is a few patches old at this point:

?imw=5000&imh=5000&ima=fit&impolicy=Lett

 

I suppose nothing but mainsails could be an interesting challenge.

Edited by cerberusti
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Thank you for responding,

Did you do all the roundtrip (Kerbin-->Eve-->Kerbin) with this ship or only the trip back from Eve (this ship looks rather small); I mean if only the trip back, you should have needed a bigger ship to take this one to Eve right? I need the schema of the entire ship that takes off from Kerbin T=0. Could you also post it as well?

Thanks again

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Hum... I would say 'hold your horses' until you have unlocked the aerospike engine, for a classic 'non-propelled' asparagus ascent. And build your rocket in the most aerodynamic way that you can, as Eve's atmo is... well, soup :D 

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That was from sea level to orbit (I think I actually launched it from the ocean).

The ship itself is a little bit old, but the numbers it gives in the mechjeb panel for TWR and DV at both sea level and vaccum should be near what you want for stages.  You need a lot of DV, and you need a ton if you lack the engines to punch through that super dense atmosphere quickly.  You also need to pay attention to aerodynamics, as it matters quite a bit.

 

I do not have a screenshot of the landing cage, but that was less... good.  I had a large heat shield in front, and two more in the back providing drag so it faced the correct direction.

Edited by cerberusti
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Landing on and returning from eve is considered one of the hardest things in the game to do (other than landing on Jool and returning, and a moho round trip  :P). You have to send a craft with enough dv to orbit kerbin  and then some to eve, enter it through the atmosphere (very difficult without 10m heat shields ) land it, send it back up and have it rendezvous with an orbiter, (u could attempt to refuel on gilly but that’s advanced) and have the orbiter return home. I’ve never done it either (I just started a different save where I’m ditching JNSQ career grind and just going to try to land on all the planets and such), but my suggestions would be to do a duna landing and maybe even a laythe/ Tylo landing to A) unlock the full tech tree and B) get practice with interplanetary trips before you go into hardcore mode. Also check kerbalX for crafts that are eve return capable just to see some examples.

Best of luck!

Edited by Daedalus3000
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Well thank you all guys. It appears I have to grind some sidemissions+other repetitive stuff to unlock more tech. I still don't understand the way missions are ordered tho; I think the mission progression should have been designed to allow players to progress smoothly. I mean other options like catching asteroids are much easier. And as for Eve on top of all that you're saying I also have to perform many multi stage+dockings? Gimme a break there is no way I can accomplish this. Goodbye career mode I guess maybe sandbox is better. Anyway sorry for all that poodleing and thanks again.

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I haven't gotten a mission to land on Eve yet (last time I got one it was like 200K for mining and taking off with 600 ore, and I was like 'eff that' and declined) but I would probably make use of mining. Have a mining module that you can use to fill up your rocket and dispose it when returning, and have a return module on Eve orbit to dock with  and return to kerbin

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The contract system is 'flawed' or 'works' in that if you land on a body, it will give you contracts "to" and "from" that body (ie tourist trips, where to be successful they need to safely return to Kerbin). And also it will come up with "extract ore from...." contracts where its a huge amount of ore to get into orbit or somewhere else.

Another indirectly related one is where a space station is specified, but with a huge amount of liquid fuel or ore on it, and/or a piece of equipment which will never be used (resource scanners not in polar orbit, etc).

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I have been playing KSP for about 8 years but have never managed to return from Eve surface. It can't be done. The people who say otherwise are big stinky fibbers. 

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2 hours ago, Vanamonde said:

I have been playing KSP for about 8 years but have never managed to return from Eve surface. It can't be done. The people who say otherwise are big stinky fibbers. 

Observe:

 

Edited by Admiral Fluffy
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41 minutes ago, Vanamonde said:

I have been playing KSP for about 8 years but have never managed to return from Eve surface. It can't be done. The people who say otherwise are big stinky fibbers. 

Oh yeah? (:

 

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46 minutes ago, Vanamonde said:

I have been playing KSP for about 8 years but have never managed to return from Eve surface. It can't be done. The people who say otherwise are big stinky fibbers. 

At least now I don't feel as bad as before :D

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3 hours ago, Vanamonde said:

I have been playing KSP for about 8 years but have never managed to return from Eve surface. It can't be done. The people who say otherwise are big stinky fibbers. 

False. I celebrated a return from the surface of Eve by going cow tipping later that night.

 

No, wait...it turns out that I've been playing on and off for 7 years and Eve is the only actual surface I've never returned from.

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  • 2 weeks later...

A pilot, an engineer, and a scientist land on Eve.
 

mp7oqOg.jpg


That's it. I don't have a punchline for you at this point. But then, the return ascent has not yet been attempted...

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On 6/29/2021 at 1:40 AM, ecyenskeyn said:

Well thank you all guys. It appears I have to grind some sidemissions+other repetitive stuff to unlock more tech. I still don't understand the way missions are ordered tho; I think the mission progression should have been designed to allow players to progress smoothly. I mean other options like catching asteroids are much easier. And as for Eve on top of all that you're saying I also have to perform many multi stage+dockings? Gimme a break there is no way I can accomplish this. Goodbye career mode I guess maybe sandbox is better. Anyway sorry for all that poodleing and thanks again.

You can use propellers to build a "helicopterocket" that could lift out of eve's atmosphere on propeller power alone. It skips most problems, and it's much lighter than purely rocket systems. And there are some rotors fairly low on the tech tree.

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On 6/29/2021 at 11:22 AM, Vanamonde said:

I have been playing KSP for about 8 years but have never managed to return from Eve surface. It can't be done. The people who say otherwise are big stinky fibbers. 

Wow. Got on and off about a year after I started playing. Landing craft was about 145 tonnes mass though, I had mods installed that made shipping it to Eve easier (extra nuclear engines from KSP Interstellar Extended; love that mod pack) - though it itself was all stock parts, and do admit to using hyperedit a few times in the testing stages. Basically the same general design principles that cerberusti posted, but considerably squatter. Wanted to get >8000 m/s packed in that thing though to make sure I could land at any spot desired and return. My aim was to basically explore Kerbol system going inward to the inner planets first then the outer planets next ... sure hit a snag at Eve tho lol :(

(One important point is not trying to boost the entire thing off the ground. You'll want to assemble your craft in Kerbin orbit using several launches from dockable pieces - at the very least, the lander and the cruise stage should be launched separately. Lifting 145 t up to Kerbin orbit is tough enough on its own.)

 

5 hours ago, n.b.z. said:

A pilot, an engineer, and a scientist land on Eve.
 

mp7oqOg.jpg


That's it. I don't have a punchline for you at this point. But then, the return ascent has not yet been attempted...

Beautiful! I love Eve, it's my favorite stock planet by far in terms of how it looks.

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Just suggestions. You can always assemble larger craft in orbit (pre-dock bug) to give you enough dV, or you can make a seperate ship (tank/probe) to launch into Eve orbit and use that to refuel the main ship for its landing, ascent, and return home.

 

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On 6/28/2021 at 12:30 PM, ecyenskeyn said:

~ (cannot upload image for some reason "https://imgur.com/a/Hka5y4d") ~

Since no one else has mentioned it, yet;

 

you have to enclose your link with the brackets [ ] with img in between and include the .jpg (.png) after the link - closing with the /img in brackets.

[*img*]photolink.jpg[*/img*] minus the '*'s.

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On 6/28/2021 at 10:29 PM, ecyenskeyn said:

Did you do all the roundtrip (Kerbin-->Eve-->Kerbin) with this ship or only the trip back from Eve (this ship looks rather small); I mean if only the trip back, you should have needed a bigger ship to take this one to Eve right? I need the schema of the entire ship that takes off from Kerbin T=0.

Generally speaking, you don't design 1 ship to go to from Kerbin, to Eve, back to Kerbin. It is much easier to break the mission down into different phases. Also, you should not design a ship to go from the surface of Eve back to kerbin. You should design a craft to go from the surface of Eve to orbit of Eve. That cuts about 1,440 m/s from your design requirement, which means what you lift to orbit is much smaller, which means your Eve Ascent vehicle is much smaller, which means what you need to launch your Eve ascent vehicle into orbit of Kerbin is much smaller.

You get to eve orbit, and have another ship waiting to rendez-vous with it and either take your kerbals back to kerbin, or refuel the last stage of the eve ascent vehicle so that it can get back to kerbin.

You will want to land at a high altitude, because sea level ascents from Eve are the hardest ascents. The map here may help (use the color relief eve map to find high altitude equatorial places): https://ksp.deringenieur.net/

Now, Eve has a thick atmosphere, you lose a lot of dV to reduced Isp, and to drag. You want lower stages with good Isp in thick atmospheres. The mainsail is useable, but the mammoth, vector, and aerospike do much better. 

Eve has a strong gravity, so you lose a lot to gravity, you want a high TWR, the aerospike isn't great here (its OK as a core stage of an asparagus rocket. The better engines are the vector and mammoth.

A seldom considered stat is thrust to cros section area. To avoid lots of drag, you want a tall and skinny rocket, but those rockets tend to have poor TWR. The vector is the king here. If doing a standard rocket only veritcal launch, staging ascent, Vectors are great. My "standard" ascent rockets used a pair of vectors, some drop tanks, and an aerospike core stage. It seems like with your tech, the best bet is a Mainsail asparagus launcher with something smaller for the final stage that makes it to orbit.

On 6/29/2021 at 8:22 PM, Vanamonde said:

I have been playing KSP for about 8 years but have never managed to return from Eve surface. It can't be done. The people who say otherwise are big stinky fibbers. 

har har

On 6/29/2021 at 8:56 PM, Admiral Fluffy said:

Observe:

 

That looks rather exploity to me, and I wonder how he provides electrical power. The part count to supply power via RTGs would be enourmous. I wonder if he doesn't use the infinite EC cheat. There are certainly some shenanigans with part clipping and fairings.

I have made reusable Eve cargo shuttles, but I do 2 stage reusables:

Spoiler

The 2 stage craft ascends on prop power:

Ljsw0Om.png

Managing power for the ascent is a big task, power consumption is prodigious. Lots of batteries are used. At a certain point, more fuel cells extend flight time more than adding more batteries. It also has some RTGs, for recharging batteries when all fuel is consumed, because the idea is that it will fly back to where it launched from under electric power. It will launch from a mining post to refuel.

Obviously, if the mining post is not at sea level, it will not consume so much power on ascent, and may get to fly higher.

Yj2d0in.png

244 EC/second disappearing despite the fuel cells going (EC consumption goes up at higher altitudes).

When EC runs out, its time to shut off the rotors, fully feather the prop-fan blades, and light the rockets (which helfully generate some EC for the 1st stage to use when it comes back down: uI6hAz6.png

I climb at 60 degrees, because for reusable 2 stage designs ot work, I need a high Apoapsis to give some hang-time, but I also would like some forward velocity to make the 2nd stage perform better:

rm7z9dz.png

In this test, they connect via 2 standard 1.25 m docking ports, in practice, they will be replaced with shielded docking ports, and connected after launch (really wish they would change that). Anyway, after 1st stage burnout,they must disconnect:

UfWUoX9.png

tqAplhG.png

6pGR7IW.png

htYtCus.png

zFdfa29.png

qm0CJfF.png

MWth9ep.png

One must switch back before the 1st stage falls too much.

1st stage reentry is... exciting, and took a while to get right, with many failed attempts

RB5qBlB.png

Ox5ASA0.png

Akh5lQa.png

Below is an earlier 1st stage that has landed, that is not the original launch site:

a0jIPU8.png

Even unloaded, and at slow speed, EC consumption is a problem:

PpmsoFY.png

but it does generate some EC,

2p7sDOK.png

Landing speed is super low though:

qnQEv6U.png

pHO6kFL.png

To fly back, I would time warp to recharge the batteries, and then try to go back on battery plus RTG output. The empty flying weight would mean that it could cover a lot more distance than the ascent on batteries.

Alternately, I could have 2 mining outposts, decrease part count a bit, but rely more on fuel cells. Take off at the western mining outpost, land at the eastern one, refuel, fly back to the western one.

The orbiter would reenter, glide back to the surface, and the 1st stage would fly under prop power and connect on the ground.

Here was a non-cargo carrying version:

qVPYlul.png

The props on the front were problematic. So was having the cockpit so close to the front on reentry of the orbiter.

I have tried SSTO designs using props, but I found 2 stages gave much better payload fractions:

msX9ddX.png

i7OtmmK.png

(oops, that seems to be my custom Eve config for my 3x rescale system)

Spoiler

6ncrv81.png

 

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Sometimes a simple solution is the best one. I used this:

https://kerbalx.com/Mephisto/Simple-Eve-Ascent-Vehicle

With a few modifications (heat shield, retro-rockets to deorbit, some wings to stop it flipping on re-entry and parachutes for landing), it’s easily capable of landing on Eve and returning- with a suitable landing site, the higher the better.

PWPZITf.png

RJWBQRO.png

sXQ8zyr.png

NfO88mw.png

And I did it twice on two different Grand Tour missions (hence the docking ports between the first and second stages, I had to connect it up in Eve orbit before going down) with the added weight of Kerbalism’s life support and supplies; without that it’ll be a lot more efficient. Requires Making History though (or you could use the Restock+ copies of the 1.875m tanks instead) but no robotic shenanigans to micromanage, just good old-fashioned brute force rocketry.

Fun fact- without the radiation hazards of Kerbalism, you can use that upper stage to land just about everywhere else in the Kerbol system- Tylo is possible with a descent stage and Laythe might be too, but planes are a better choice there; add some parachutes and Duna is feasible too and all the other planets/moons/whatever “Dres” is can be managed with fuel to spare.

Edited by jimmymcgoochie
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On 7/19/2021 at 4:04 AM, KerikBalm said:

That looks rather exploity to me, and I wonder how he provides electrical power. The part count to supply power via RTGs would be enourmous. I wonder if he doesn't use the infinite EC cheat. There are certainly some shenanigans with part clipping and fairings.

With a sufficiently optimized ascent, you don't use rtgs.  Prop ascent phase should only take 12-15 minutes.  If you run the math, rtgs only beat batteries for ascents taking at least 35.5 minutes.  So if you use batteries you are looking at  2-3x less mass and about 7x lower part count vs rtgs.

As for payload fraction, even with relatively small designs (2 vector, 4 nerv) payload fractions of about 5% are achievable, so with the much larger scale, and the greater skill (Brad is better than me at optimizing sstos) I can totally believe that Brad was able to reach 6%

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