General Question Some questions about Space Shuttle

[laukejas]

I have some questions about Space Shuttle operations in Orbiter 2010.

I have familiarized myself with basic space flight rules, played around with DG and other futuristic spacecraft, but I've decided to go for a challenge, and learn more about Space Shuttle.

I've managed to do a successful ascent and docking with ISS many times, that thing is clear to me. But after that, I'm stuck on reentry. I just can't make it. I've done numerous reentries with DGIV, XR2 Ravenstar and XR5 Vanguard, (using BaseSync and AeroBrake MFDs). Procedure is always the same: make PeA and ApA about 150-200km, burn retro on the other side of the planet, then face velocity vector, raise nose to 40 degrees angle of attack, and make fine adjustments. This works with most spacecraft, but not with Space Shuttle. Two problems:
1) Impossible to keep 40 degrees AOA, even with RCS and ailerons together - at around 50km nose drops down. I've tried Attitude MFD, but since it uses only RCS, it's useless. The same with AeroBrake MFD autopilot.
2) Space Shuttle bounces back from atmosphere many times, and I can't reenter at all. Only if I keep AOA at about 80 degrees, Space Shuttle finally stalls. Why does DGIV, X2 and X5 stall, while Space Shuttle just bounces back and forth?

I've tried Shuttle Fleet V4.5, but I still can't reenter properly.

What am I missing? As far as I red everywhere, instructions are the same: synchronize with the base, burn retro half orbit before base, and keep 40 degrees AOA. But this doesn't work at all. Any help would be appreciated. As well as some explanation how to keep nose up - ailerons and RCS together can't do that.

One more question: is there some Space Shuttle addon that is UCGO compatible? And the one that has damage model, so that reentry would be less forgiving?

 

[Mantis]

STS is pretty difficult (compared to the Deltaglider) to successfully carry out a manual re-entry and landing. Up to version 4.7 running on Orbiter 2010 (NOT P1), you can use AutoFCS to carry out your deorbit and landing automatically. That will give you a good look at the process. Unfortunately, AutoFCS does not work with Orbiter 2010 P1. A new version is in testing and development but there is no release date and we just have to be patient. You best bet to do it manually is to watch a few automated returns and then try it yourself utilizing the GPC MFD which gives you the guidance tools that you need. In addition to holding an attitude of 40 degress, the shuttle makes a series of "S turns" to bleed off energy. These turns are steep banks left and right that are done wile maintaining the 40 degree attitude.

 

[laukejas]

Sorry, how can I watch these automated returns? Where? AutoFCS doesn't work, so is there a substitute? I've tried those S turns too, but I can't keep 40 degrees AOA while doing that. Nose just drops down. What can I do about it?

 

[Mantis]

Sorry, how can I watch these automated returns? Where? AutoFCS doesn't work, so is there a substitute? I've tried those S turns too, but I can't keep 40 degrees AOA while doing that. Nose just drops down. What can I do about it?

If you're using shuttle fleet 4.5, you must be in Orbiter 2006 - 4.5 doesn't work with Orbiter 2010. If you are on Orbiter 2006 and Shuttle Fleet 4.5, then AutoFCS does indeed work. AutioFCS also works with the pre-P1 release or Orbiter 2010 and Shuttle fleet 4.7.

 

[laukejas]

Well, I'm using Shuttle Fleet 4.5R2 with 2010 P1. It works... Except AutoFCS.

 

[Mantis]

Well, I'm using Shuttle Fleet 4.5R2 with 2010 P1. It works... Except AutoFCS.

Right....4.3 was the last one for Orbiter 2006. My mistake. In that case you can't use AutoFCS until the new verson (which I understand is being tested) comes out. Only thing you can really do is use the GPC MFD re-entry data screens and try to fly it manually. As I said, the shuttle uses a series of S-turns to bleed off energy on the way down.

 

[zerofay32]

One problem you may be having that is keeping you from maintaining the AOA is you might be coming in too step and at too high Vertical Speed (VS).

Some things to consider:

• 
  Find an old version of the Fleet and watch AFCS in 2006 to see exatly how it is done.

• Start using Shuttle Fleet shuttles, I belieave that the areodynamics of the defult Atlantis aren't correct (or rather, the Fleet is more accurate). And you can utilize the entry screens of the GPC MFD which are the same for the real shuttle.

• Make sure that when you perform your D/O burn that your PeA is around 58km.

• Acording to AFCS and watching the GPC screens, during entry up until TAEM
  your VS should never be above (below) ~-200. And for much of the first bank, you should try to keep VS around 0 around 75 to 80 km in Alt. And set the trim so that it will help to keep the nose up (remember to reset it at TAEM).

Here is a link to a shuttle entry Tutorial but I haven't looked at it to see how acurate it is. http://www.eharm.net/shop/freeware/orbiter/tutorials/orbiter_instrument/deorbit.html

Best thing to do is to try to find a video that you can take notes from. It posible to do a manual shuttle entry, just takes some study.

 

[laukejas]

Thank you very much. I'll try that. And hopefully, someone will release working FCS with 2010 P1...