Flight Question high energy re entry

[hugix]

I'm haivng some difficulties with re entry from the Moon to the Earth in the XR-2.

I come in with a PEa of around 60-65 kilometer. Do a small re entry check (9), all systems green with a AOA of around 60 degrees.

All but one of my tries ended in one of two scenarios;
-A APa that is way to high and extends the mission by days
-I turn the XR-5 into a 1000 little pieces flying very very fast.


If I use more AOA the ship tends to wobble a lot, making it hard to control. when i lower my AOA I brake to little and the ship burns up at PEa.

Are there any tricks or good guides/videos that can help me understand re entry better?

 

[MaverickSawyer]

Yeah. With a direct lunar reentry, you need to perform an inverted reentry, aka heads down. Basically, your bank angle is greater than 90*.
Use the lift being generated downward to keep you inside the atmosphere as you bleed off speed. Once you're going less than 7 km/s, you can roll back upright and reenter normally.

Hope this helps.

 

[boogabooga]

Search for inverted re-entry.

There should be a tutorial somewhere.

edit: :ninja:

 

[hugix]

I've tried inverted a few times but kept blowing up. Will try that some more than.

 

[statickid]

It's not so difficult as you would think. However, if you do not wish to do this inverted reentry, the other less efficient method is to use your engines to slow down before you reach the earth :shifty: But that's waaaay less fun!!

 

[Cras]

Ever since the AoA hold autopilot in the XR-2 was upgraded to allow functionality at inverted bank angles, it is actually really easy to perform direct re-entry from the moon. Just be ahead of the vertical speed, you start to see you sink react sooner rather than later or else you will find yourself in a very bad place. Mix in some Aerobrake MFD to gauge where you will end up in relation to your target bace and you will be mastering inverted re-entry in no time.

 

[hugix]

Tnx everybody! I am starting to get the hang of these re entry profiles. About half of my tries are completed with success. In my first try today I had a almost perfect landing at CSSC. ( to bad the vert speed was a bit high and destroyed the landing gear).

 

[Tommy]

There is an older tutorial (annotated playback) showing this:

[ame="http://www.orbithangar.com/searchid.php?ID=3660"]Home Direct[/ame]

This flight is also included in The IMFD Full Manual:

[ame="http://www.orbithangar.com/searchid.php?ID=4142"]IMFD Full Manual/Playbacks[/ame]

This was done in Orbiter 2006, so it's a bit dated. FOr one, The XR's autopilot now supports inverted flight so you don't need to maintain the AoA manually using COG offset and trim - which makes this MUCH easier. The only other change is that you will want a lower PeA in the current version - about 5 - 8 km lower than in the tutorial.

It is quite possible to perform this type of re-entry when returning from Mars as well - probably Venus also but I haven't tried that yet.

 

[boogabooga]

This might be useful as well:

http://www.orbiter-forum.com/showthread.php?t=34197

 

[hugix]

tnx all! I got the hang of it now and such a type of re entry ois now one of my favorite missions to fly!