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Re: Space Shuttle

Postby japreja » Fri Sep 18, 2015 10:48 am

Don't know if it helps but this is a good shuttle page to bookmark http://www.nasa.gov/centers/johnson/news/flightdatafiles/ and maybe archive. Don't know how long NASA will keep this information available if they continue upgrading their sites.
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Re: Space Shuttle

Postby Johan G » Fri Sep 18, 2015 11:06 am

Wow! Great resource. :o 8)
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Re: Space Shuttle

Postby japreja » Mon Sep 21, 2015 8:18 am

@Thorsten
Here is an additional satellite, SPARTAN-201. This satellite has no moving parts that I have found but does have at least 12 thrusters. I've included the preview .png image in RGBA format and a Readme with some more info in the zip along with the blend and .ac files for testing. I have not had a chance to reinstall FlightGear yet to check the model for the proper size. The protruding pin in the center top of the SPARTAN is the attach point, as seen in the image below.

The model is courtesy NASA 3D Resources and is slightly modified from the original .lwo to reduce vertices.

Preview of the model:
Image
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Re: Space Shuttle

Postby Thorsten » Mon Sep 21, 2015 12:23 pm

Very nice :-)

It may be a while till I integrate this, but I guess I'll store it with artwork for the time being (do we have other info such as mass of the satellite?) - I'm currently thoroughly mired in guidance and pointing code. But I have just succeeded in letting the Shuttle perform automatic OMS burns for a PEG 7 target entered into the guidance system - which somehow is very cool.

It still refuses to use OMS TVC during the burn for attitude holding for some reason... but I'll get to the bottom of this yet.
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Re: Space Shuttle

Postby Thorsten » Mon Sep 21, 2015 5:23 pm

And... it works - with all the steps to set the burn just as in the manual:

Major Mode 104 display with a PEG 7 target of 50 ft/s 33 s retrograde burn locked in, maneuvered to attitude and waiting for the EXEC key to start engines:

Image

Attitude control handed over to OMS TVC during the burn - note how the thrust vector passes through the CoG of the Shuttle:

Image

And burn ends after 33 s according to plan :-)
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Re: Space Shuttle

Postby japreja » Mon Sep 21, 2015 8:33 pm

The mass of SPARTAN-201 for its first mission was 1360.0 kg as noted on http://nssdc.gsfc.nasa.gov/nmc/spacecraftDisplay.do?id=1993-023B. I am not sure if it was upgraded or modified on later flights, the documentation mostly discusses the data it gathered. I am still trying to find the payload data on the pallet that held it during launch, it will most likely need to come from mission video which I can do in Blender.

I love how the Space Shuttle is turning out, I am going to my local office supply store to find out the cost of printing out the Crew Ops Manual and the DPS manuals so I can work with them easier. I'll try the same for the JSBSim manual if it is allowed so I can start diving into the code a bit easier. I don't expect it to be more than $40-$50 for all three.
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Re: Space Shuttle

Postby Thorsten » Fri Sep 25, 2015 7:23 am

Some work on failure detection and CWS messaging.

The way this operates in the Shuttle is as follows:

If there is a problem detected which isn't an emergency (which has its own independent alarm system), then a flashing line appears at the bottom of every DPS screen. In this case I get a R OMS QTY indicating that my OMS fuel is dropping below 5% for some reason. Acknowledging the message stops the flashing, and doing it again brings up the next from the stack (if there are more).

Image

Inspection of the fault summary page reveals the last 15 fault messages with their timestamps and shows a few RCS-related problems as well:

Image

The GNC systems summary page shows that RCS manifolds 3 and 5 have issues (have experienced a 'fail off' condition) and the manifold isolation valves have been closed to prevent any leakage.

Image

It's a neat system, though tedious to code...
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Re: Space Shuttle

Postby Hooray » Fri Sep 25, 2015 7:30 am

It's a neat system, though tedious to code...


for failure management/modeling, it would make sense to look at galvedro's Nasal framework (that is, if you haven't already): http://wiki.flightgear.org/A_Failure_Ma ... FlightGear
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Re: Space Shuttle

Postby Thorsten » Fri Sep 25, 2015 7:35 am

This is just failure detection and announcement, the actual failure modeling is all encoded in the JSBSim systems simulation - I have some fairly complicated cascades of failure modes to deal with, and hence all the systems are written with component failures in mind from the onset.
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Re: Space Shuttle

Postby Hooray » Fri Sep 25, 2015 7:39 am

makes sense, certainly easier than piggy-backing everything later on
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Re: Space Shuttle

Postby japreja » Fri Sep 25, 2015 5:35 pm

On the final approach I seem to be crashing about 5 to 10 feet above ground in the 3.7 nightly. I saw, a few weeks ago, that someone stated that scenery needs to be regenerated for each version of FG, is this why I am crashing a few feet above ground? This is in the development version of Space Shuttle at KTTS, I'll try another aircraft and post in scenery if the same happens with it.
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Re: Space Shuttle

Postby Richard » Fri Sep 25, 2015 7:10 pm

Thorsten wrote in Fri Sep 25, 2015 7:23 am:Some work on failure detection and CWS messaging.


The displays are really coming along now. It might be tedious - but the results are worthwhile. It's these sort of details that make the difference between a good model and a great model.
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Re: Space Shuttle

Postby Thorsten » Sat Sep 26, 2015 5:39 am

On the final approach I seem to be crashing about 5 to 10 feet above ground in the 3.7 nightly.


Crash as in 'software ceases to function' or as in 'Shuttle is destroyed'?

I've had one weird experience at KTTS where there seemed to be some wrong ground-interaction right at the beginning of the airfield green (i.e. the terrain may have a genuine fault there) but I came in very low and all other approaches at KTTS with the touchdown point well into the runway worked actually fine.

Usually you should not have to bother with scenery issues as a user, so your setup is fine as such.
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Re: Space Shuttle

Postby japreja » Sat Sep 26, 2015 6:39 am

Crash as in destroyed, it was at the tip of the runway 33, within a foot or two of the beginning of the tarmac just over the green area before touchdown. I'll have to be careful and stay above that point.
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Re: Space Shuttle

Postby Bomber » Sat Sep 26, 2015 12:05 pm

Good to see failure/damage modelling being done... I look forward to treating it with the same level of respect that you've shown mine.
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