Landing on Eve in 1.0.4

[Kermen]

I consider myself to be pretty capable at Kerbal Space Program. Having played since about 0.18, I can meet just about any challenge I put myself to. So when my latest career game presented a "land a station on Eve" contract, I thought "sure, I'll give it a go!" After all, my last mission was landing probes on Duna and Ike, and that was almost trivial.

But Eve is just too big and too hot in 1.0.4. I can't figure out how to get to the surface. The atmosphere chews through my ablator in minutes, even on the shallowest aerobraking trajectory. I never get a chance to open my chutes.

I've looked but I can't find any guides or examples of an Eve landing since the heating changes in 1.0.3, so I've come to ask:

Does anyone know how to get down to Eve's surface safely? All I can think of is to bring thousands of dv and soft land on thrusters.

Edited July 20, 2015 by Kermen
answered

[Foxster]

Air brakes.

[Kermen]

Slowing down isn't the problem. Not exploding is the problem. I didn't try airbrakes but I can't imagine that something designed for maximum drag would fare better than a heatshield.

[Foxster]

Slowing down isn't the problem. Not exploding is the problem. I didn't try airbrakes but I can't imagine that something designed for maximum drag would fare better than a heatshield.

Well this survives re-entry fine with just air brakes...

Edited July 20, 2015 by Foxster

[Kermen]

What's your surfaceV at entry?

[Foxster]

Can't remember but it was a fairly shallow re-entry from about 100km.

[selfish_meme]

Your going to have to reduce your velocity, I think orbital is around 3k/s if you are coming in faster than that you will probably have issues. 100Km orbit to re-entry is definately survivable even without heat shields, just air brakes.

[Foxster]

Got a picture of your craft? Or better still post your craft file and maybe we can find a fix.

BTW...is this manned or unmanned?

Edited July 20, 2015 by Foxster

[Kermen]

Unmanned. I'll be trying again with airbrakes and less horizontal velocity, and you can trust you'll hear from me if I keep failing.

[Foxster]

Dunno if this might help. All the heat-sensitive bits are occluded and the only bits that show any heating during re-entry are the air brakes. The engine is just for de-orbit as the single 'chute and air brakes will take it down to a 4m/s landing.

[Sharpy]

From low Eve orbit to 85km PE, probes with unshielded solar panels, everything exposed, no heatshield whatsoverer - not even considerably heated. Simply skirt the atmosphere until it captures you and provide enough non-aerodynamic surface not to dive bullet-like.

[Warzouz]

Dunno if this might help. All the heat-sensitive bits are occluded and the only bits that show any heating during re-entry are the air brakes. The engine is just for de-orbit as the single 'chute and air brakes will take it down to a 4m/s landing.

http://i.imgur.com/VBf3NMp.png

So basically you used the big probe core as a shield to the rest of the ship ? 2 airbrakes provided the slowdown.

I've a Eve window in 30 days, I'll start designing a space station stuffed with 6 or 8 probes and a small ship for Gilly. I'll look into you design.

[Laie]

Airbrakes appear to be the easy way out: mount them so that they're occluded from reentry effects. This way they can create drag and slow you down, without overheating.

If you want to be a little more serious about it, it's recommended to enter tail-first. Any visible surface pointed into the wind should be either an engine or a heat shield. Any important radial bits should be hidden in the shadow of something.

Plan C, wings and a plane-like entry. Requires a lot of wing and you need to be ever so gently.

[Mastikator]

Well this survives re-entry fine with just air brakes...

http://i.imgur.com/DAzpYkZ.jpg

How did you prevent it from instantly exploding when it touched the upper atmosphere? When I put my probe at 95km x 89km orbit it took about 15 seconds to overheat and explode, how effective are airbrakes at the edge of the atmosphere?

[Sharpy]

There's something wrong with your game if you exploded at such an orbit. 1km into the atmosphere? *boggles*. I performed a successful Eve airbraking with 86km periapsis from the very edge of the SOI, no airbrakes, no heatshields, nothing even moderately heat-resistant.

Edited July 20, 2015 by Sharpy

[Foxster]

How did you prevent it from instantly exploding when it touched the upper atmosphere? When I put my probe at 95km x 89km orbit it took about 15 seconds to overheat and explode, how effective are airbrakes at the edge of the atmosphere?

That sounds like some heat-related bug. Got a picture?

[Sharpy]

better a .craft file

Somebody (me?) might try finding what's overheating. I have a suspicion that some large, draggy, relatively heat-conductive and heat-resistant part gathers a lot of heat from air drag, and rapidly forwards it to some cubic octagonal strut or some other puny thing that has no heat capacity (and wouldn't overheat by itself due to tiny size = almost no drag, but gets overheated through conduction.). That's just a wild guess though. Without the craft, that's all it is.

[Edax]

I got a primitive Mun probe lander designed to return Mun data to land on Eve (cause I got a contract to escape the Kerbin early on), I set the target to skim through the atmosphere at 86000m, and I made sure to roll the spacecraft when going through the atmosphere so it evenly heated, but it took like 30 damn aerobraking laps before the thing slowed down enough to land.

[Warzouz]

30 laps is a long aerobrake...

How hot was you probe after one pass ? Maybe you could have tried to go deeper in atmo ?

[Edax]

(Maybe it was 20 laps? I lost count after the first hour) If it went deeper, it would explode. The overheat temperature would rapidly trigger, and the heat would rise very rapidly. I found it best to actually not use the heat shield in aerobreaking, instead pointing the body prograde, and just rapidly rotating keeping all the parts at 80-90% heat. One of the reasons I had to aerobreak so much was that I hard to burn all of the chemical rocketfuel and half the monopropellent just to manage an orbit, but I had to go for a shallow entry into the atmosphere because Eve's atmosphere is like a brick wall at high speed. The worry I had near the end was that when my orbit was no longer eccentric, the probe wouldn't cool down fast enough between dipping into the atmosphere, so I had to maintain a shallow 86-85000m aerobreaking height. It's when I finally began landing did I use the heatshield.

Edited July 20, 2015 by Edax

[Kermen]

I did it again with brakes. Like the right man in the wrong place, it made all the difference in the world. Those things are magical. Despite the name, I never would have thought to use them for aerobraking maneuvers or re-entry. I figured they were just for aircraft. Thanks for the tip.

edit: reading some other posts about how Eve is a fiery deathtrap, I think maybe there is a glitch in the heating, maybe from having the game open too long, or loading a quicksave? I don't know what the cause might be, but I was literally exploding at 80km before, but relaunched the game, tried again with brakes, and coasted coolly to the surface.

Edited July 20, 2015 by Kermen

[selfish_meme]

The atmospheric boundary is a bit messed up for all planets bar Kerbin, the zone between instant death, aerobraking, and no effect is quite small. I expect it will be fixed in the next update. Most people just come in too sharp and too fast expecting it to be like Kerbin.

[Warzouz]

BTW, I'm working on a space station, and I want to aerobrake at Eve.

The 2 first Hyperedit tests did better than I thought. I simulated a near escape 4600m/s at PE. The station don't have any heatshield or aero braking device (it's just a test)

- Without the fairing, the gigantor blasted rapidly

- With fairings, the docking ring blast after a long heating.

I targeted 85km, then 82km. I think I can manage the overheating. My main trouble is that the vessel barely slow at all. I think it would need dozens of aero braking.

I'll try with a big array of airbrakes .

Edit : Station is 100T

After 5 pass at 75km, I only reduced the speed by 500m/s at pe. The ablator is totaly gone by the 4th pass. Heatshield goes up to 99% but don't blow.

I only lost 2 of 12 air-brakes. It seems the airbrakes on griders blew immediatly, but those on the hitchhikers did well.

I could try adding much more airbrakes. I could combine a detachable upper pod with air brake and slowdown fuel reserve.

Edited July 22, 2015 by Warzouz

[Anglave]

This has come up a few times recently. I highly recommend the three pages of this thread. Three more pages here.

The short answer is, the relationship between drag and heating is currently broken. This is particularly noticeable during the new "turbulent flow" heating, which is engaged if your craft is moving faster than a certain velocity at a given altitude. This doesn't seem to have been balanced with interplanetary aerobraking in mind. Most such maneuvers will flip the "turbulent heating" switch, and pretty much instantly cook anything that's not effectively just a giant heat shield.

The disconnect also means airbrakes are magical.

Edited July 22, 2015 by Anglave