Eve Aerocapture Altitude

[samwiseiam25]

I'm launching an Eve system exploration mission in about 2 in-game days and I have an armada of ships I'm ready to send including an Eve rover, Eve probes, a Gilly lander, and science lab and fuel bunker space station modules for future exploration and mining missions. My question is, since I haven't gone to Eve since the last update, what is a good aerocapture periapsis for ships coming into Eve from Kerbin. I can't dip too low into the atmosphere because I (a. don't want to de-orbit some of my modules, and (b. don't have heat shields on many of my crafts, so I can't brake super hard and low in the atmosphere. I'm just looking for an altitude that will at least get me into an elliptical orbit around Eve without burning my craft up in the atmosphere.

Here are some images of the crafts so you can get an idea of what's going on.

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Thanks!

Edited November 1, 2015 by samwiseiam25

[Tatonf]

Without heatshield you can forget aerocapture. Even with them it's very difficult.

[NathanKell]

It's possible up to 6km/sec entry velocity with a shielded Mk1-2 pod if you get your entry corridor correct. That means any fully-shielded craft of similar ballistic coefficient should perform similarly.

[RA3236]

I aerocaptured on Eve as well, but I burned up with a fully shielded ship at the highest possible altitude. I don't recommend doing this.

[Foxster]

Not really going to happen because of the buggy way atmospheres other Kerbin's are implemented at the moment.

Your choices are to wait a week or so for 1.0.5 when it should be fixed or take along more dV and brake with engines.

[Sanic]

Eve's atmosphere is terribly harsh even at low reentry speeds (2000 m/s). As Foxster (kind of) said, aerocapture is not a viable method for orbit as of 1.0.4.

[juanml82]

You can't aerocapture those ships and, honestly, the game should be designed to prevent you from doing so - otherwise the heat mechanics would turn into a waste of CPU.

You don't have heatshields, you have plenty of exposed stuff and you're using 2.5m parts instead of the spaceplane parts, which resist heat better.

[NathanKell]

Just what speeds are we talking about here? (Navball in Surface mode at 90km alt--what's the speed?) Also the periapsis.

[FancyMouse]

Eve aerocapture is possible, is fun to do, but you need to design for it and a random ship is not going to make it.

My testing showed the entry speed is about 5.2~5.5 km/h - note I was not using optimal Hohmann transfer. I usually pick one transfer that spends ~200m/s more fuel but arrives earlier. Using optimal Hohmann I think it can get down to ~5km/s, but still I don't think the heat situation can improve too much.

[samwiseiam25]

Darn, that's disappointing. I may use infinite fuel to circularize at the destination to replicate the effect of aero capture then.

- - - Updated - - -

I'm in orbit around Kerbin at the moment, I haven't left yet for Eve. I'm doing just a straight Hohman transfer and I was basing my presuppositions about aero capture on a similar mission to Duna which established its orbit by passing through the atmosphere multiple times after a Hohman transfer to the system.

[FancyMouse]

Well, Duna experience can help you except for heat. Duna entry speed is just about 1.2~1.3km/s from what I remember. It produces way less heat than Eve.

The tricky thing about aerocapture from aerobrake is, you only have one chance. If you don't capture, you get thrown away by your own speed and no second chance. And from what I remember testing a random ship entering Eve, the overheating altitude is way higher than the capturing altitude (something like 82km vs. 72km for identical ship).

[Two]

You can go for a Periapsis of 87km at best without an unshielded craft. This is not enough to get you into and orbit and you cannot land in any way without appropriate equipment.