If I ever make it back from Eve

[Reinhart Mk.1]

I'm literally never going back again, this is probably the hardest challenge in any game i've ever played. No real point here just venting, went through about 20 ship designs, last one made it to 14k then ran out of fuel. Didn't even get past the first layer of the atmosphere

[The Aziz]

You need 8k d-v. Now you don't even need mods to know if you have enough.

[Reinhart Mk.1]

I looked it up before i launched and i had that amount

[The Aziz]

Hmmm. But maybe it was 8k in vacuum, on the surface it could be much less, depending on used engine?
My last (and only) Eve rocket blew up on reentry so I never had the chance to test if it actually is able to return...

Edited February 16, 2019 by The Aziz

[RealKerbal3x]

5 minutes ago, Reinhart Mk.1 said:

I looked it up before i launched and i had that amount

It’s probably your ascent trajectory. Launching from Eve is not like launching from Kerbin. You need to go pretty much straight up until at least 20km in order to get out of the dense lower atmosphere.

[Reinhart Mk.1]

4 minutes ago, The Aziz said:

Hmmm. But maybe it was 8k in vacuum, on the surface it could be much less, depending on used engine?
My last (and only) Eve rocket blew up on reentry so I never had the chance to test if it actually is able to return...

oh i used kerbal engineer and set it to eve, i launched so many times so i think one of my engines exploded at some point but this new stage has like 15k delta v so fingers crossed

3 minutes ago, RealKerbal3x said:

It’s probably your ascent trajectory. Launching from Eve is not like launching from Kerbin. You need to go pretty much straight up until at least 20km in order to get out of the dense lower atmosphere.

yuuuup did this too, i was honestly just planning to go straight up and once i'm out of the entire atmosphere just circularize from there

[RealKerbal3x]

2 minutes ago, Reinhart Mk.1 said:

yuuuup did this too, i was honestly just planning to go straight up and once i'm out of the entire atmosphere just circularize from there

That’s going to take a lot more than 8k delta-v. You’ll need to be pitched over to the horizon before you leave the atmosphere.

[Espatie]

You can save a lot of dV by landing in the right place on Eve.

[Reinhart Mk.1]

16 minutes ago, RealKerbal3x said:

That’s going to take a lot more than 8k delta-v. You’ll need to be pitched over to the horizon before you leave the atmosphere.

well not the WHOLE way up but the majority, now im currently back in VAB trying to figure out WHAT STRUTS I HAVE TO PUT IN THE RIGHT SPOT SO THIS THING IS STABLE. Honestly it's just my pride at this point, i could easily skip this but i just can't. why did they even make it possible to land on this planet hahahaha

[RealKerbal3x]

55 minutes ago, Reinhart Mk.1 said:

well not the WHOLE way up but the majority, now im currently back in VAB trying to figure out WHAT STRUTS I HAVE TO PUT IN THE RIGHT SPOT SO THIS THING IS STABLE. Honestly it's just my pride at this point, i could easily skip this but i just can't. why did they even make it possible to land on this planet hahahaha

I would recommend using autostruts set to grandparent part instead. They help with structural rigidity without contributing to drag or mass. You need ‘advanced tweakables’ turned on in settings to get them.

[Gargamel]

With some testing, and patience, it's not that hard.  I mean, it's difficult, but do able. 

One option to consider is to have the lander land empty, and refuel via ISRU.   Save some mass that way

In this pic, the 6 man return vehicle landed on it's own, empty, and the rover with the crew landed somewhere else, drove to the lander, refueled it, and then they went home.  But it would be pretty trivial to change the design a bit to have the ISRU under the lander, and have it drop off during launch. 

 

[Reinhart Mk.1]

Well I'm 90% confident this build will AT LEAST get me into orbit of Eve after landing, I appreciate all the advice but i dont wanna (how do i put this) kinda bite off of someone else's design, it's more rewarding that way to me haha

anyways here's my death trap

 

[Gargamel]

1 minute ago, Reinhart Mk.1 said:

bite off of someone else's design, it's more rewarding that way to me haha

Oh I hear that.  I prefer designing my own.   But sometimes I have to look at what others have done in order to get the correct inspiration for my designs.   

I tend to prefer reusable interplanetary motherships over one and done single use vessels, so when I was building this, the only thing I cared about was getting back to orbit, with enough dv to dock. 

[Reinhart Mk.1]

3 minutes ago, Gargamel said:

Oh I hear that.  I prefer designing my own.   But sometimes I have to look at what others have done in order to get the correct inspiration for my designs.   

I tend to prefer reusable interplanetary motherships over one and done single use vessels, so when I was building this, the only thing I cared about was getting back to orbit, with enough dv to dock. 

same here! i get a general idea of what to build but i stop kinda searching after i find a good starting point, i was gonna use some kinda of mothership for it but right now im just trying to see if this design is even worth launching, so far it seems okay, we'll see though haha

[Foxster]

You don't need 8k dV to make orbit from sea level of Eve. The least I've done it with is around 5.8k dV.

The reason a lot of craft need more is because drag losses are so high in Eve's souposphere.

You need to reduce drag as the priority. That means: dropping absolutely anything not essential for reaching orbit, really minimising the payload and removing anything at all that adds any drag. As well as having the slimmest design with the smallest number of stacks.  

I also recommend using the Gravity Turn Continued mod when testing a craft so that you can tweak and repeat a launch with the same profile each time so that you know its a changes to the craft that is changing how much dV you are falling short of and when there are improvements due to a design change. Once you have optimised your craft this way "in the simulator" you can fly it for real as a mission. 

 

Edited February 17, 2019 by Foxster

[Foxster]

9 hours ago, Reinhart Mk.1 said:

same here! i get a general idea of what to build but i stop kinda searching after i find a good starting point, i was gonna use some kinda of mothership for it but right now im just trying to see if this design is even worth launching, so far it seems okay, we'll see though haha

You picture link doesn't work btw.

[Foxster]

11 hours ago, RealKerbal3x said:

It’s probably your ascent trajectory. Launching from Eve is not like launching from Kerbin. You need to go pretty much straight up until at least 20km in order to get out of the dense lower atmosphere.

That's only useful if your craft is draggy. If you make a little craft with very low drag then it becomes efficient again to start the turn much lower. The key though being to have a zero AoA to minimise drag. 

[KerikBalm]

It also depends on your engines, some get really bad Isp at 5 atm, and the difference between sea level and vacuum is worse than on Kerbin.

from my experience, you want vectors, as they have a really high thrust to cross section ratio, so your rocket can be really tall and thin

[Reinhart Mk.1]

Welllll my "beautiful" design landed on eve, but on takeoff it would literally do nothing but flip and fly straight into the ground I'll post a video to show what i mean

[Reinhart Mk.1]

Wow I didn't even render this video, just uploaded straight to youtube and the quality isn't that bad but yeah here's my failed design

https://www.youtube.com/watch?v=RmfpKYe1J_M&feature=youtu.be

[Superfluous J]

37 minutes ago, Reinhart Mk.1 said:

Wow I didn't even render this video, just uploaded straight to youtube and the quality isn't that bad but yeah here's my failed design

https://www.youtube.com/watch?v=RmfpKYe1J_M&feature=youtu.be

DRAG DRAG DRAG that thing is draggy. Most importantly, it's draggy on the top so wants to fly backward.

Parachutes? Decouple them. Top of the pod? Cap it. Fuel ducts? Lose 'em and use cross-feed. Wings? Too high. I'd drop them myself and use the Vectors for steering and stability. And leave the gimbal at 100. You WANT lots of gimbal.

But literally any upward facing surface without a nose cone will kill you. Downward facing (engineless) ones will hurt too.

Edited February 17, 2019 by 5thHorseman

[Laie]

@Reinhart Mk.1 One engine isn't running. Clearly visible in the staging list. At 1:42 I see that it's one of the asparagus engines -- hence the flip.

You'll get a lot of flak for carrying legs and parachutes and whatnot. My main concern when looking at that vessel is that it's a lot of engine for very little fuel. Like, 1/2 of your vessel mass is engines -- and powerful Vectors to boot. You're certainly not short on TWR.

For comparison, here's my one-person thingy. Please note that the lifter proper is just the 9 parts in the middle, all the rest was for getting to Eve in the first place.

 

Edited February 17, 2019 by Laie

[herbal space program]

 

45 minutes ago, Reinhart Mk.1 said:

Wow I didn't even render this video, just uploaded straight to youtube and the quality isn't that bad but yeah here's my failed design

https://www.youtube.com/watch?v=RmfpKYe1J_M&feature=youtu.be

Well I think I can offer a a few observations here. The reason you are flipping out on takeoff is that you are missing an engine on the back side of your craft! You can clearly see it in the indicator on the staging sidebar as well. If you set the thrust limiter on the opposite engine to zero, you should be able to take off more or less vertically. That's because you also have really excessive TWR with all those Vectors on such a small lander. Also, your total dV indicator on the sidebar reads only 2.7 km, which is not enough if it's true, and if it's not it means something in your staging sequence is out of whack.  I'm inclined to believe it's more or less true, because you are apparently taking off like a shot with a missing engine and the others set to half power. An efficiently designed Eve lifter will take off in a stately fashion at full throttle, gaining speed at only around  2-3 m/s/s right at the start.

7 minutes ago, 5thHorseman said:

But literally any upward facing surface without a nose cone will kill you. 

I was going to make that comment as well, but on closer inspection I saw that he had circular intakes on top of his stacks, which actually mitigate drag pretty effectively.

Edited February 17, 2019 by herbal space program

[Starhawk]

10 hours ago, Foxster said:

You don't need 8k dV to make orbit from sea level of Eve. The least I've done it with is around 5.8k dV. 

That's interesting.  I hadn't realized the lower boundary was quite that low.

Is that straight vacuum dV?
 

21 hours ago, Reinhart Mk.1 said:

I'm literally never going back again, this is probably the hardest challenge in any game i've ever played

Eve landing and return is the 'final boss' of the stock game.

I understand the sentiment, though.  I wrote a little parody of a song some time ago about the difficulties of Eve.

Happy landings!

Edited February 17, 2019 by Starhawk

[herbal space program]

1 hour ago, Starhawk said:

That's interesting.  I hadn't realized the lower boundary was quite that low.

Is that straight vacuum dV?

Happy landings!

There is no way a sea level Eve ascent is possible with only 5.8km of vacuum dV.  Even as actual atmosphere-adjusted dV that claim seems pretty iffy to me. That's because if Eve had no atmosphere, you would need to expend at least around 4 or so km/s of vacuum dV just to get going fast enough to stay in orbit. And that's only if you take off horizontally in vacuum, accelerating to that speed instantaneously, i.e. that is a hard theoretical limit and not any kind of practical one. And even setting that aside, there is no way you are pushing anything that size through all that soup for just an extra 1.8km/s over that  limit. If however what we are talking about what the dV indicator says when you are sitting on the ground, then that sounds about right.

 

For an example, here's a sea-level Eve lifter I made that can survive a ballistic re-entry fully fueled and then take off to orbit again, which was one of the hardest design exercises I've ever taken on:

https://imgur.com/a/7jFsTG2

 

You can see that the dV indicator reads 5.3 km/s while it's descending through the upper atmo, but reads only 1.4km/s when it's near the ground (OK, that particular time it actually went in the Drink, but that's beside the point!). Its actual vacuum dV when staged as intended is something like 12km/s, and configured as shown it makes Eve orbit from sea level  with around 2km/s dV to spare in low TWR orbital maneuvering ability.

 

....So I've now gone on to test the minimum suicide burn dV myself by hacking the Eve atmo with HyperEdit. At the lowest normally safe orbit of 91km, I was going 3215 m/s. To drop my PE to 1600m, I had to lose exactly 100m/s of velocity. When I hit terrain at 3km, about 90 seconds before PE, I was going 3554 m/s.  At the rate I was accelerating, I estimate that if I had made it down to 1000m I would have been going around 3580 m/s. Adding it up, I find that to attain the lowest-energy safe orbit possible from the surface of Eve, an absolute minimum of 3680m/s is required.  

Edited February 17, 2019 by herbal space program
added new content based on testing