Challenge: use aerobraking or aerocapture to enter orbit from an escape trajecto

[Rocketeer]

Can you do this:

1. Launch on an escape trajectory

2. Turn back and burn into a second escape trajectory grazing Kearth's atmosphere

3. Use atmospheric drag to slow down the craft down to orbital velocity

4. Do a burn at apogee to stabilize the orbit

or...

3. Use Kearth's atmosphere repeatedly aerobraking in order to reach orbital velocity from an initial escape trajectory (using minimal rocket thrust)

or...

Go into a high and eccentric elliptical orbit that grazes Kearth's atmosphere and aerobrake without engine thrust in order to circularize the trajectory around the planet (with just one thrust at the end perhaps).

[Tom4H4wK]

I can tell you that this unfortunately does not work. Tried it on an 6000 m/s escape trajectory and no matter how flat your trajectory is, the second you enter the atmosphere at around 35 km, you brake down to about 1800 m/s. Hard. From there on it is just plummeting down to the surface, unless you apply some thrust.

[Girlinhat]

If you use the atmosphere to slow yourself, then your lowest point in orbit will skim the atmosphere, and thus slow you down with every orbital pass. It should be possible to skim the atmosphere to lose speed, and then thrust slightly to stabilize orbit, but you can't do it purely with skimming.

[foamyesque]

If you use the atmosphere to slow yourself, then your lowest point in orbit will skim the atmosphere, and thus slow you down with every orbital pass. It should be possible to skim the atmosphere to lose speed, and then thrust slightly to stabilize orbit, but you can't do it purely with skimming.

I'm not sure it's possible at all; at 34.5, you essentially hit a wall. Maybe-- maybe!-- if your perigee was at 34.499 for only a second or two, but...

[Salda007]

If you use the atmosphere to slow yourself, then your lowest point in orbit will skim the atmosphere, and thus slow you down with every orbital pass. It should be possible to skim the atmosphere to lose speed, and then thrust slightly to stabilize orbit, but you can't do it purely with skimming.

The problem is that Kearth's atmosphere doesn't quite work like Earth's. Kearth's has a much sharper transition, right at 34,500m up. You don't so much 'skim' the upper atmosphere as 'slam into it headlong.'

[Girlinhat]

Even more-so, this makes it impossible to purely aerobrake. As I said, it's possible to skim/slam briefly and then correct using small thrusts, but not possible alone.

[DoctorEvo]

I think it might be doable with tweaked .cfg files. Setting all the drag values to some miniscule number may make it just slippery enough to pull it off.

But yeah, the 34.5km transition is much too sharp to pull this off in a realistic fashion.