Spaceplane re-entry guidance

[ElWanderer]

To include:

1. de-orbit burn (at the right time to place the periapsis beyond the target given that we expect to drop short) - simple from an Equatorial orbit, but much harder from an inclined orbit
2. glide at an appropriate angle of attack to bring the predicted landing point close to the target (if overshooting, pitch well up to encourage lots of drag, basically)
3. pass over to manual/automatic landing guidance

I have a test script that does this for Equatorial orbits, albeit with much room for improvement.

Note - this is a separate issue as (a) automated landing is going to be very complicated and (b) this part tends to involve loss-of-signal, so there is no ability for manual control all the way down unless you have a pilot on-board.

[ElWanderer]

Testing in progress:

I think there is a tendency to overshoot currently, which tends to mean making S-curves or even full rotations after taking manual control. Partly, this is because we aim relatively close to the runway. Partly, it's because we request a fairly low angle-of-attack when marginally overshooting, whether we are half the world away or right up close. Partly, it may be down to how well a given craft can maintain a high angle-of-attack at high velocity in the lower atmosphere.

[ElWanderer]

Some kind of stall detection would also be useful. Holding a moderate angle-of-attack for a spaceplane similar to the second screenshot above led to a flat spin. Usually I would take over before that happens, but I wanted to see how low and slow the script could get the plane.