Jool vs Laythe aerocapture in 1.0

[Wjolcz]

I want to send stuff to Laythe, but I'm not sure what's better with new aero and reentry heat.

Is it better to go straight for Laythe aerocapture, which looks fast and extreme, or longer Joolian and then after that go to Laythe? What is less likely to kill me?

I guess there's always the third option of retro gravity assist + burn without the need of even touching both atmos. Just like Galileo did on a fly-by of Io?

Edited May 4, 2015 by Veeltch

[Jouni]

Laythe aerocapture is safer than returning from the Mun, if you approach Laythe from behind. With a good encounter, the speed should never exceed 3000 m/s.

The following should work:

1. Get an encounter with Jool.
   
2. Match the orbital inclination of Jool and set your periapsis to about 21200 km (on the right side of Jool).
   
3. Adjust your arrival time by tweaking prograde/retrograde and radial/anti-radial, until you get an encounter with Laythe.
   

[Wjolcz]

Thanks. I actually know how to do all the manouvering, but was not sure about the speeds and heating effects of 1.0.

[panzer1b]

Jool is ALWAYS a very safe bet, even with craft that have 0 airbrakes as it has a nice large radius, and if you do it just right (not too deep, not too shallow), you are almost always going to at least get a stable orbit (then you can continue aerobraking or instead go with a grav assist or something to alter orbit.

While direct shots to laythe are possible, you need to time it exactly so that laythe is moving away from your incoming vector on approach. I have managed this once, but it is technically doable (but i believe a jool aerobrake is less fuel useage as you only need minor burns to stop aerobraking at the right height and to intercept laythe with the proper PE, ive managed to get away with under 100dV for total course changes after entering laythe's system. A direct laythe capture would be most efficient, but unless you time it exactly when relative velocity is lowest, you arent going to survive the reentry (or will just be unable to get stable orbit).

Also, trying to get a aerobrake when laythe is on the other side of jool (going towards you) is suicide as ive already tried this, 6km/s is fun but not exactly safe (and i ended up killing val on that one, had to revert a save).

[Jouni]

While direct shots to laythe are possible, you need to time it exactly so that laythe is moving away from your incoming vector on approach. I have managed this once, but it is technically doable (but i believe a jool aerobrake is less fuel useage as you only need minor burns to stop aerobraking at the right height and to intercept laythe with the proper PE, ive managed to get away with under 100dV for total course changes after entering laythe's system. A direct laythe capture would be most efficient, but unless you time it exactly when relative velocity is lowest, you arent going to survive the reentry (or will just be unable to get stable orbit).

I guess that you're playing stock. With MechJeb or any other mod that allows you to adjust the prograde/radial/normal components of a maneuver node numerically, precise encounters become trivial. If your ship has RCS, you can often even set the aerobraking altitude before entering Jool's SoI.