Space Shuttle Ultra 1.25 Revision B development

[SiameseCat]

Agreed. I think the main problems are with entry and landing; launch and on-orbit are simulated fairly well.

The only major problem with entry is that you can't fly the entry by hand; the control surfaces aren't strong enough. I'm not sure if this is a problem with the aerodynamics or the control surfaces.

At one point we were discussing changing the scenario file format; do we want to do this before or after the new release?

 

[DaveS]

The only major problem with entry is that you can't fly the entry by hand; the control surfaces aren't strong enough. I'm not sure if this is a problem with the aerodynamics or the control surfaces.

Actually the major problem with entry is that it's impossible to maintain a 40° AoA while also conducting the rolls.

It's kinda like trying to do the roll program entirely by hand.

 

[SiameseCat]

That's what I meant; my experience has been that it's impossible to maintain a 40° AoA at all once the RCS thrusters are disabled. The maximum I could get was about 36°. I'm not sure why this is occurring; it might be because the aerodynamics are wrong, the control surfaces aren't strong enough, and it might have something to do with the shuttle's weight distribution (i.e. where the lift force is relative to the CoG).

 

[DaveS]

That's what I meant; my experience has been that it's impossible to maintain a 40° AoA at all once the RCS thrusters are disabled. The maximum I could get was about 36°. I'm not sure why this is occurring; it might be because the aerodynamics are wrong, the control surfaces aren't strong enough, and it might have something to do with the shuttle's weight distribution (i.e. where the lift force is relative to the CoG).

Well, the CG should be pretty far aft for entry and landing which is the primary reason why the heaviest payloads are mounted as far aft as possible, to help shift the CG aft in the event of a RTLS or TAL.

It's also the reason for the FRCS dump after the de-orbit burn.

 

[Donamy]

Roll and re-entry aren't flown manually, so why the need to simulate them ? Just concentrate on the things that are done manually. IMO

 

[SiameseCat]

They can be flown manually, although it's normally done by autopilot. Also, the only working autopilot is AFCS ,which requires changes to the installation, and is a bit tricky to use with SSU. Another thing is that the problems we're having indicate that something else is wrong with the aerodynamics simulation, which I'd like to fix.

 

[DaveS]

They can be flown manually, although it's normally done by autopilot

Yes. Manual is done by taking the PITCH, ROLL/YAW channel PBIs to CSS. Standard is AUTO.

 

[DaveS]

Bug: AP doesn't support resuming a quick-save during stage 2 ascent. Leads to the vehicle getting invalid orbital data and gets shot out of the solar system at insane velocities.

---------- Post added 08-09-10 at 12:27 AM ---------- Previous post was 08-08-10 at 10:28 PM ----------

Checked in a cleaned up and enhanced version of the SSME exhaust texture which looks much better than the old one.

 

[SiameseCat]

AP bug should be fixed now.

 

[DaveS]

AP bug should be fixed now.

Confirmed. Also something I noticed was that the SSME exhaust was several m off from their correct location in the Z axis when resuming the scenario.

Other things that seems to have gone missing in the 2010 version:

• MPS GOX Purge streams
• SSME flame-trench steam/smoke
• The "twang"

 

[SiameseCat]

SSME exhaust should be fixed now; I'll look at the other problems.

 

[SiameseCat]

The twang and SSME smoke should also work now.

 

[DaveS]

The twang and SSME smoke should also work now.

Confirmed. Also fixed in the process is a long-standing bug that caused the SSME smoke to be delayed by 1 second from SSME start.

---------- Post added at 07:33 PM ---------- Previous post was at 08:30 AM ----------

Now that Orbiter will natively support localized light sources; i think we can remove our nightlight hack workaround and implement it natively through the use of actual local light sources at the pad.

Then we also can implement the payload bay floodlights.

 

[Urwumpe]

Great news

We can then also do the engine effects better.

 

[DaveS]

Great news

We can then also do the engine effects better.

Yup. Something we need to simulate when it comes to the floodlights is the unavailability of the docking and FWD BHD lights on Discovery and Endeavour. According to the SCOM those lights have been removed on those vehicles due problems with the water loop cold plates for those lights.

The A7U switches are still there on those orbiters but they don't do anything.

 

[DaveS]

Checked in a mesh of the Xenon lights used at KSC today. It's something I had a for a while now.

 

[Urwumpe]

Sadly, I don't see custom light-maps for VCs yet. Those would really help for doing the night lighting and flood lights.

Now to a question that is really waiting for being asked after seeing the Xenon lights: You don't seem to be hiding a mesh of the ET barge somewhere? Or a SD-40 train engine with the SRB cars?

 

[SiameseCat]

Yup. Something we need to simulate when it comes to the floodlights is the unavailability of the docking and FWD BHD lights on Discovery and Endeavour. According to the SCOM those lights have been removed on those vehicles due problems with the water loop cold plates for those lights.

The A7U switches are still there on those orbiters but they don't do anything.

Sounds like another mission file entry.

 

[Urwumpe]

Sounds like another mission file entry.

There can never be enough. :lol:

I already look at writing a small Java application for producing the mission files, Java would have the advantage that it is simpler to attract beginners for maintaining the tool, compared to MFC or wxWidgets. Only some specialist command line tools would then be better in C++, when speed & memory does matter again.

 

[DaveS]

Sadly, I don't see custom light-maps for VCs yet. Those would really help for doing the night lighting and flood lights.

Now to a question that is really waiting for being asked after seeing the Xenon lights: You don't seem to be hiding a mesh of the ET barge somewhere? Or a SD-40 train engine with the SRB cars?

I used to have a complete Pegasus mesh but it was lost about a year ago when one of my two internal HDDs failed.

Shouldn't be too much of a problem recreating it.