Suggested aerobreaking altitudes for Kerbin, Eve, and Duna

[jamgoth]

I'm trying to get an asteroid around Kerbin at circular equatorial orbit at 139-145km. I'm also going to put a satellite around eve and duna at that same altitude. What should my aerobreaking altitude be to achieve this goal?

[Streetwind]

That depends on the velocity with which you arrive.

On Kerbin, try 50km to play it safe, or 45km for a more aggressive approach. It's probably better to accept having to do a second pass, if it keeps you from going to low and not coming back up again.

[mhoram]

You could try alterbarons aerobraking calculator.

[Geschosskopf]

I'm trying to get an asteroid around Kerbin at circular equatorial orbit at 139-145km. I'm also going to put a satellite around eve and duna at that same altitude. What should my aerobreaking altitude be to achieve this goal?

IMPORTANT NOTE: Aerocapture is trial-and-error due to zero in-game instrumentation on its effects. So before you do it, be sure to F5. Then give it a try and if you don't like the results, F9, tweak the Pe up or down as needed, and try it again.

Anyway, aerocapture Pe altitude depends on 3 things:

• Velocity at Pe, as Streetwind said
  
• Whether or not you have FAR
  
• Whether or not you have Deadly Reentry
  

The real goal here is to at least capture into a closed orbit without having to burn any fuel, even if that orbit is a huge ellipse that takes you out nearly to the edge of the SOI. Once captured, you can just make multiple passes, tweaking your Pe up or down as desired, until you finally get an Ap about where you want, then circularize there. The number of passes you can do is limited only by the time you want to spend doing it and any life support or electrical constraints you might have.

Assuming you don't have the above mods installed, at Kerbin I'd be FAIRLY aggressive when coming in at what is essentially interplanetary speed with an asteroid. 35-38km is what I'd start with. Again, this is trial and error so if that doesn't do what you want, reload and try something else.

For Duna, usually somewhere between 11-13km works just fine. The main variables there are the speed on arrival and whether the ship is going to orbit Duna or go out to Ike.

For Eve, it also depends on whether you're staying there or going to Gilly. But I find somewhere between 65-70km usually does the trick.

[Jananton]

Am I the only one who thinks you're bound to expose your kerbonauts to intolerable G forces when one reduces speed like this?

Greets,

Jan

[LameLefty]

Am I the only one who thinks you're bound to expose your kerbonauts to intolerable G forces when one reduces speed like this?

Greets,

Jan

You won't. If you aerobrake carefully, you can do so with peak g forces rarely exceeding 6 - 7 for a couple minutes. While incredibly uncomfortable and physically taxing, it shouldn't be fatal.

[Geschosskopf]

Am I the only one who thinks you're bound to expose your kerbonauts to intolerable G forces when one reduces speed like this?

Probably. The rest of us just don't care. And being as Kerbals routinely do headers off the VAB roof and walk away unharmed, I doubt they care, either .