Return mission to Eve

[Cirocco]

So I’ve been wanting to do an Eve mission ever since my first successful interplanetary trip to Duna, but I set myself a few limitations for doing so:

1)It can be really hard to pinpoint a precise landing spot on a planet with an atmosphere (especially one so thick as eve’s) so we need to take worst case into account: lander needs to be able to make it to a stable orbit from sea level

2)We need science! Why else go to a planet if not to do experiments? (Yes, okay, it’s KSP, we go because we can and because it’s pretty. But still!) The lander needs to be able to bring back a lot of science data if nothing else. Bringing back the experiment itself would be nice, but the data is the most important.

3)Possibly the most important of all: the lander needs to look sleek and at least halfway believable. It follows from this constraint that she needs to be as light as possible. The heavier the craft, the harder it is to push it all the way into orbit and out to Eve and the less believable it gets. Also, a hardened pod is absolutely required. No saving weight with external command seats. No one in their right mind would consider going to orbit sitting on the outside of a rocket, especially not on a hostile world.

4)Optional: try to do it without the parts (or more precisely, engines) released in ARM. Not strictly necessary, but some of the new parts seem just a tiny bit too powerful. Using ARM to push it into orbit and (possibly) for the interplanetary stage is fine, but preferably not for the lander.

Having set these limitations for myself I discovered over the course of the following months what a cold and ruthless **** Eve can be. As if added gravity wasn’t bad enough, that atmosphere is a KILLER:confused:.

KSP being what it is, limitation number 3 was by far the toughest one. I can throw together an Eve lander without many problems, but they look like absolute behemoth monstrosities that should never even have made it to Kerbin orbit.

But after literally months of building, designing and calculating (I actually learned a ton about the laws and equations governing rocket engineering), dozens of tests - both on Kerbin and a few on Eve itself – about four complete design overhauls and having to come up with an entirely new staging concept, I finally managed it: a lander that can go down to Eve’s surface (sea level) and get a single kerbal back to a 100000m orbit, and which looks like a ship that someone with half a functioning brain would actually consider boarding.

The Orpheus Mk IV.

She comes in at 160 tons and a smidge without all the peripherals (landing gear, science pods, parachutes, etc) and uses a modified 4-way symmetry asparagus design, with some added functionality to counteract that early loss of thrust that almost all asparagus designs suffer from and which is so incredibly important on Eve.

I can’t post pictures right now since I’m at work (and I also need to figure out how to post pictures/albums since I’m a total forum n00b) but I’ll try to show you guys how she looks and performs later. I still need to design and build a way to get the Orpheus into orbit and an interplanetary stage to get her to Eve, but I plan to fly the actual mission this week, so expect pictures by then!

Happy flying, may your engines never overheat, your Isp always be high and your TWR always be greater than 1.

Cirocco

Afterthought: MY GOD it took so much time, so much curses and frustrations, even leaving KSP for a while thinking it wasn’t possible to design a sleek-looking Eve lander that gets to orbit from sea level, but she got there in the end. Never give up, never surrender!

Oh yes, if anyone could tell me where to find the .craft file (or whatever it is called) I’ll post that up too.

Edited April 22, 2014 by Cirocco
typo clean-up

[CalculusWarrior]

Congratulations! I have yet to attempt an Eve mission myself, and I've been playing for over a year! Like you say, the planet is cold and unforgiving.

A great way to share pictures is to upload them to somewhere like imgur.com, and the KSP forums allow you to add imgur albums right into posts. Simply make the tags

[imgur]xxxxx[/imgur]

The x's are the last little code in the album URL.

Also, .craft files are located under your savegame, so go to Kerbal Space Program\saves\<your save="" game="">Ships\VAB and it should be there, among all your other crafts in that save.</your>

Edited April 22, 2014 by CalculusWarrior

[Cirocco]

Ah, sweet, thanks a lot CalculusWarrior! I'll see about the pictures and .craft file when I get back to my gaming rig

[NecroBones]

Awesome! I look forward to seeing your design. I just completed my second Eve landing+return over the last few days (I wanted to do it again after being mildly cheaty in my first attempt). My lander was definitely an ugly asparagus behemoth, and the lifter from Kerbin was likewise quite huge, since I did it in one launch without assembling in orbit.

I'm sure there are more elegant ways to do it, but it seems like most people opt for pancake landers and the like.

[Red Dwarf]

I've been working on my own Eve return vehicle, and I came up with a great way to save weight. I'm sending a rover out to Eve first, which has all the science I could possible want. All my little Kerbonauts have to do is land nearby, and the rover will come to them. Grab the science and go! I'm curious to see what you did, though. Gimme pictures!

[Cirocco]

... it seems like most people opt for pancake landers and the like.

yeah, when I did my initial research on how other people tackled eve return missions, one of my first thoughts was "No pancake design!"

I actually scrapped one working lander design because I thought it was too wide at the base and too thin in the stage above that. It was in fact that very restriction that led me to my current staging setup which is a modified asparagus design, just slightly less efficient but retaining high thrust for a much longer amount of time.

I'm also thinking of posting a thread with "stuff I learned when trying to take off from Eve" because one of the big ones I learned is that retaining high thrust is more important than efficiency in eve's lower atmosphere. Because the massive drag really slows you down hard, being near terminal velocity saves you so much more fuel in comparison with (regular) asparagus staging.

I've been working on my own Eve return vehicle, and I came up with a great way to save weight. I'm sending a rover out to Eve first, which has all the science I could possible want. All my little Kerbonauts have to do is land nearby, and the rover will come to them. Grab the science and go! I'm curious to see what you did, though. Gimme pictures!

I essentially did the same, only my science pods are attached to the lander. I take the measurements as the lander is descending and once it hits the ground, science pods are ejected, kerbal grabs all the science and puts it in the command pod.

Again, I'll see if I can post pics soon. Might not be tonight, but I'll definitely try to do it this week.

Edited April 22, 2014 by Cirocco

[Cirocco]

Alright here are some pictures! (assuming I did everything correctly to upload them)

Javascript is disabled. View full album

I screwed up the first ascent because I was too busy taking screenshots and I cannot multitask for crap. The last couple screens of the map view show you that it is in fact possible if you make a proper ascent. I do a straight up burn until 25000 meters, where I start a slight gravity turn. At 50000 meters I go almost full horizontal until I reach just over 100km apoaps and then just cirucalrize on (and I do mean completely ON) the apoaps.

this is just a proof of concept, actual mission report will follow later and will be posted in the relevant forum section.

I'll see about posting the .craft file soon too.

Hope you guys enjoy!

Cirocco

Edited April 22, 2014 by Cirocco
Messed up teh images. works now!

[cantab]

Nice work. I think it's going to be some time before I attempt an Eve lander.

[NecroBones]

Hey, that looks like a pretty good design!

I tried to build a little taller too (no pancake), but mine is still in many ways just a typical asparagus design. I made the innermost asparagus stage the tallest of the radial tanks, for the best burn time, and the outermost 5 stages are short-tanks (alternating LV-909 and aerospikes) for just a high TWR at takeoff.

[Red Iron Crown]

A few structural and aerodynamic parts made this ascent stage fairly sleek.

[Cirocco]

looks pretty sweet red iron crown. I wonder though, can you make it to orbit from sea level with that? What kind of gravity turn do you use (by which I mean, at what altitudes do you turn and how much)?

[Red Iron Crown]

Not quite from sea level, I think it's a couple hundred m/s short (haven't tested it on Eve). I plan to add more fuel for deorbiting/landing as part of the landing equipment, might do it if there's enough left over.

I'm a MechJeb user, so my ascent profile is a straight climb to 30km, then let it handle the gravity turn gradually until 95 km. If I was doing it manually, I'd pitch east by 10-15 degrees, then chase the prograde marker for the rest of the ascent.

[iDan122]

I posted my first Eve mission in mission reports and no one cared a bit. But here there are tons of comments? Isn't this a mission report? If so, this should be moved.

[-RanZ-]

I posted my first Eve mission in mission reports and no one cared a bit. But here there are tons of comments? Isn't this a mission report? If so, this should be moved.

most people read general discussion... I would just post everything here and wait for a mod to move it to a subforum to die

[Cirocco]

The title is unfortunately chosen I admit, but I don't think this is an actual mission report. I basically was just so proud/excited because I finally succeeded in building a relatively lightweight lander that could make Eve orbit from sea level that I just went straight to the forums to throw it on here. And to see what fellow rocketeers thought of the design and/or if they had suggestions/improvements.

I haven't actually flown the mission yet, but I understand that this could be considered as a mission report. So by all means, this can be moved if the moderators feel it should be.

[luizopiloto]

I tested my lander today... this one will bring 2 kerbals back to orbit... they will go there on a capsule, with a rover... and use it to come back to orbit...

http://www.twitch.tv/luizopiloto/c/4121899