Eve Lander and return ship frustration

[mystik]

I have wasted days trying to make something for 4 kerbals to land and return from the surface of Eve. I give up. Anybody have any crafts that work?

[KerikBalm]

The largest eve ascent vehicles I've made are for 3, but a 4th wouldn't be too hard.

Pics of your one that has come closest to success?

[bigcalm]

The key with Eve ascent rockets is to make them really aerodynamic.  Make them as slippery as a fish, add fairings as required, even closed intakes can help (for some reason closed intakes are aerodynamically very low drag).   Oh, and have around 7000ms delta v (this should give you a margin).  Of course, there's a trade off.  Making it really aerodynamic means really tall and narrow.  This is generally bad news for actually landing the damn thing in the first place as it'll tend to topple over.  So you either have to compromise on aerodynamics or build out some Acme corporation landing rig.  Landing and ascending from Eve really is hors categorie of kerbal space program.

Edited December 29, 2017 by bigcalm

[OhioBob]

Please describe the problem you're having.  We understand you can get it to work, but what about it is not working?  Pictures are also worth a thousand words.

[purpleivan]

I put a 4 man return vehicle on Eve back in the v0.24 days named the Eve Party Boat.

It was aerodynamic as a blunted brick, but that wasn't as big an issue then as it is now. The mission to get it there was on the ridiculous side as it had to be launched almost empty of fuel and then filled in Kerbin orbit by a fleet of tankers.

If I was to do it again (I must have another go at it), the vehicle would be a lot more aerodynamic and make use of ISRU to fuel it for the ascent to Eve orbit.

 

Edited December 29, 2017 by purpleivan

[Ten Key]

Moved thread to the Gameplay Questions section of the forum.

[mystik]

My problem is that I am also delivering a rover. I can get to kerbin orbit, then refuel and get to Eve. It lands, it separates into two parts before landing. I even refuel. Then going back is a nighmare. But I just have to land somewhere with at least 3000m altitude. Then it works. My design is far from aerodynamic because of the constraints of carrying the rover, which leaves a big coupler at the top of my rocket. I cannot add pictures because imgur has failed today.

 

 

[IncongruousGoat]

25 minutes ago, mystik said:

My problem is that I am also delivering a rover. I can get to kerbin orbit, then refuel and get to Eve. It lands, it separates into two parts before landing. I even refuel. Then going back is a nighmare. But I just have to land somewhere with at least 3000m altitude. Then it works. My design is far from aerodynamic because of the constraints of carrying the rover, which leaves a big coupler at the top of my rocket. I cannot add pictures because imgur has failed today.

Why not land the rover separately and then drive it over to wherever the lander touches down?

[Aegolius13]

54 minutes ago, mystik said:

My problem is that I am also delivering a rover. I can get to kerbin orbit, then refuel and get to Eve. It lands, it separates into two parts before landing. I even refuel. Then going back is a nighmare. But I just have to land somewhere with at least 3000m altitude. Then it works. My design is far from aerodynamic because of the constraints of carrying the rover, which leaves a big coupler at the top of my rocket. I cannot add pictures because imgur has failed today.

Aerodynamics are extremely important with Eve's thick atmo, so I would redesign to avoid this issue if at all possible.  You could send the rover in an entirely separate lander, or put in in some kind of cradle at the base of your lander, and have the ascent vehicle decouple from that when it lifts off.  

Can you provide a screenshot of your current craft?  That would greatly help us identify specific steps that might help.  General tips: use only the highest efficiency ASL engines for the lower stages (Mammoth, Vector, Dart), keep your aerodynamic profile extremely clean, and lose all possible dry weight.  To help with the last two, I like to decouple everything I don't absolutely need (like the landing legs in the pic below, parachutes, science equipment, etc).  

I have never tried a full Eve mission with more than one Kerbal,  but have it on my "some-day" list.  On a previous similar thread, I threw this thing together as an example of something that should be able to get a Mk. 3 crew cabin from Eve surface back to orbit.  But then there's the matter of how to get this thing to Eve and safely land.  It's pretty top-heavy so it might require a very level landing site, plus some more legs, etc. 

[Plusck]

My biggest problems with Eve have been getting down without burning up, and getting crew back on board after going out for science.
That's because you need thin and pointy and hardly anything other than fuel and engines on the way up, but you need plenty of drag and control on the way down, a wide and sturdy base to land on, ladders to get science back onboard (and joined ladders that are navigable on Kerbin are not necessarily possible to climb on Eve), and so on...

So the best way is probably to spam decouplers which will all fire the instant you try lifting off, shedding all that "re-entry+landing" gear.
My last time down I had a large fuel tank as a heavy base with legs on, holding most of the fuel that I needed to put into the upper stages. The idea was to land, pump fuel up, then separate and take off. Mostly worked from sea level apart from the "getting surface science back" bit.

[magnemoe]

1 hour ago, IncongruousGoat said:

Why not land the rover separately and then drive it over to wherever the lander touches down?

My tricks was to put rover between heat shield and accent stage, after you are down to subsonic speed, close or drop the air brakes and the ship will flip, now release heat shield, you might want tilted separators on it so it don't crash on top of you, 
open some parachutes on the ship to turn it the correct way, at 3-4k open all parachutes and drop the rover, you want to land the rover first so you want to fall free an kilometer or so before using the rovers parachutes. 
Switch back to ship, you would want to have the main parachutes opening in intervals to lessen the stress of them opening in the thick atmosphere. 

Ship was an 1+6 asparagus with aerospikes, kerbal on seat under fairing. This made it an pretty stubby rocket so I needed lots of fins for stability. 

[purpleivan]

3 hours ago, Plusck said:

My biggest problems with Eve have been getting down without burning up, and getting crew back on board after going out for science.
That's because you need thin and pointy and hardly anything other than fuel and engines on the way up, but you need plenty of drag and control on the way down, a wide and sturdy base to land on, ladders to get science back onboard (and joined ladders that are navigable on Kerbin are not necessarily possible to climb on Eve), and so on...

So the best way is probably to spam decouplers which will all fire the instant you try lifting off, shedding all that "re-entry+landing" gear.
My last time down I had a large fuel tank as a heavy base with legs on, holding most of the fuel that I needed to put into the upper stages. The idea was to land, pump fuel up, then separate and take off. Mostly worked from sea level apart from the "getting surface science back" bit.

Something I did on a more recent Eve return mission was to place a MK1 lander can at the base of the vehicle, in a disposable ISRU section, that the crew could be transferred to for EVA.

Like this (base section lander can in among the ISRU gubbins at the base of the vehicle, that the crew could walk in/out of.

 

Here's a more aerodynamic vehicle that could take a single kerbal to orbit.

[Plusck]

8 hours ago, purpleivan said:

Something I did on a more recent Eve return mission was to place a MK1 lander can at the base of the vehicle, in a disposable ISRU section, that the crew could be transferred to for EVA.

Absolutely! That's what I did too, only it was a lander can just above that wide fuel tank I was talking about.

The trouble was that I didn't have any "collect science" probe core or science container on the ship. So I duly went outside, got science, returned to the ship and then kicked myself for having no way of transferring the science reports to the lift-off section of the ship.

[Cpt Kerbalkrunch]

@mystik, I've thus far done 3 successful land and return missions from Eve, and I feel like I've become intimately familiar with the Purple Widow Maker. I've done a pair of 2-man returns and, the last one, a 3-man return. Eve is a unique animal, and IMO, the pinnacle of the stock game. I've learned some hard lessons, but had a great time. A successful Eve mission is the only thing that still gives me that first Mun-landing feeling of accomplishment. Some of the lessons I've learned are as follows:

First off, I pay no attention to cost or even mass. Some guys may be able to make a cost-effective Eve ascent vehicle, but I am not among them. I just use whatever I need, cuz I already know it's gonna be a loss. Second is to design the mission backwards. This is something that I think we all sort-of do with every mission (design the lander first, then the transfer vehicle, then the launch vehicle), but it's especially important on Eve. I think my first mission was a bit like yours. I would launch a behemoth, refuel it at Minmus, then see if it worked. This was incredibly frustrating and time-consuming, but it finally worked. It was an ugly ship, with Mainsails and Darts, but I was ecstatic at my success. Later, though, I felt like I got off easy because I used ISRU. I landed empty, drilled, refueled, then dumped the equipment and launched. This was before I discovered the forum, so I don't have any screenshots. I just never bothered with them back then. For my next mission, I wanted to do a 2-man return without drilling, so I went to work again. This time, I didn't wanna waste so much time (and I had finally discovered the forum and learned the use of the Alt-F12 menu), so I used my current method. I now build my ascent vehicle, Alt-F12 it to Eve orbit, turn on ignore max temperature, then get it on the ground. Launch and see if it can make orbit. This can take awhile, as you'll certainly need to make changes, but it works really well. Once I can reliably make orbit, I begin working on a way to get it to the surface. This can be as tough as designing the ascent vehicle itself. You'll notice by this time that, in order to make orbit, your ascent vehicle has become larger than you'd like. This means getting it to the surface in one piece is going to be difficult. You'll have to keep adding your shields until you can stop yourself from burning up. Once you can reach the surface, you've got it. The rest (designing a launch and transfer vehicle) is a breeze by comparison. You can make your launch vehicle a bit smaller if you don't mind taking the time to refuel at Minmus, but I've grown tired of that. I just figure it's gonna cost me 2,000,000 bucks and send it. I don't have as much game time as I'd like anymore, so I try not to waste it.

You want a 4-man return, which I've yet to do, but my last mission was a 3-man return with the Mk1-2 (which is obviously the heaviest command module in the game), so I know it can be done. You can make it work with the rover as well, you'll just have to do that much more testing to make it work. I can usually build a ship and have a pretty good idea of what it can do. However, nothing ever seems to work the way I think it will on Eve. Just because you think something should work, doesn't mean it will. You really have to put in the work and test everything. At least I do, anyway.

These are my 2 most recent Eve missions if you want to have a look.

 

2-man mission:

 

 

One of the most important lessons I've learned is the use of shields placed high up for drag. This prevents large ships from flipping and burning up during the descent. Getting it to work right was a huge "aha" moment for me. Of course, getting rid of the inflatables prevents its own challenge. With this ship, I actually attached them to SRB's. It wasn't very elegant, but it worked.

 

 

Forgive the crazy truss here. I wanted to use the Mammoth this time, but I always have trouble with ladders when the fuselage changes sizes. My Kerbals kept getting stuck on the way up or the way down. I finally scrapped the ladders and went with the Lander Can at the bottom for easy access. Of course, I couldn't get a single lined up right, so I had to use 4x symmetry. This obviously added a lot of unnecessary weight, but it worked.

 

 

Back in orbit.

 

 

My most recent success, is also my proudest. I really wanted to land and return with the Mk1-2 this time. It definitely wasn't easy, but all the more satisfying because of it. Luckily, I have a high-end laptop, cuz this monstrosity tallies in at almost 2,000 parts. There's a large upper section not in view.

 

 

I again employed the upper shields for stability.

 

 

I realize the importance of aerodynamics (especially on Eve), but I don't pay as much heed to it as your supposed to. This thing has about as much in common with a brick as a rocket. However, it is immensely powerful. This time I went with the almighty Vector. They are difficult to dissuade.

 

 

Here it is back in orbit. I really need to get back to this mission, because I'm only just short of what I need to get back to Kerbin. I think if I can make my launch a bit more effecient, I'll be able to return home on a direct ascent.

 

 

Anyway, you asked if anyone had designs that worked, so I figured I'd show you these real quick. They're obviously behemoths, but they worked, and they were built using simple trial and error. This means that, no matter what your mission profile is, you can make it work. It takes a lot of time and effort, but I really think the payoff is worth it. Hope all goes well.

 

 

[Human Person]

 

[foamyesque]

Bah, all these tail-sitting landers. Build a plane. It solves a number of interrelated issues: It gives you a means to brake on entry to manage your heat profile, it gives you control over your landing point (very useful for ISRU approaches), it gives you a low CoG and wide footprint, which are ideal for landers, landing gear is sturdy, delivering rovers becomes a breeze with cargo ramps, you can explore the planet via ISRU refills, and you can lift off with a TWR < 1. The liftoff is less efficient on a pure deltaV than a straight ascent, but it's worth it. I like a three-stage setup: A core two-stage element to execute a reasonably standard vertical-ascent->gravity turn profile, and a third stage that contains all the aerodynamic elements, landing gear, etc.

 

[Foxster]

 

Here's an Eve four-man sea-level to 110km orbit craft for you to take a look at. Might give you some ideas...

Craft file: https://www.dropbox.com/s/0mv0ujycdaxdtbz/Eve 4 man B.craft?dl=0

Needs dumpable heatshield, chutes and airbrakes bolted on but that's just detail. 

If you want to take a rover too then personally I'd drop that separately from a mothership carrying it and the crew lander. 

 

 

Edited January 1, 2018 by Foxster