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XCOR Lynx Flight Simulation for Project PoSSUM

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XCOR Lynx Flight Simulation for Project PoSSUM

Postby jreimuller » Mon Jan 20, 2014 11:40 pm

Our research project is preparing a July 2015 campaign to use a suborbital spacecraft (e.g. the XCOR Lynx) to study noctilucent clouds in Alaska. The Project is called Project PoSSUM ( and we have received some NASA support for this research.

As part of the training of the scientist-astronauts involved, we would like to develop a basic simulator that we could use for crew resource management (CRM) training between the pilot and scientist astronauts onboard vehicles such as the XCOR Lynx. We would like to use these simulations in both reduced gravity, high-G, and in multi-axis flight environments, of which we can provide suitable facilities to accommodate. The simulations would both support PoSSUM efforts and also the American Astronautics Institute's ( training efforts.

As we are currently developing the baseline system and beta-testing the initial astronaut class this year, we are delaying taking on investing partners until next year, so we are looking for collaborators that might be interested in the project that could donate efforts, though several possibilities for compensation exist (trade for astronaut training services, establishment of long-term partnerships or affiliations, delayed equity, etc.)

If interested, please contact me at the email below.

Thank you.

Dr. Jason Reimuller
P.I. Project PoSSUM
jason (at) integratedspaceflight (dot) com.
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Re: XCOR Lynx Flight Simulation for Project PoSSUM

Postby KL-666 » Tue Jan 21, 2014 2:02 am

I think someone with some authority in this project should react to this. It looks like a great opportunity to share knowledge. Maybe one of the "green" guys in this forum has enough authority?

Kind regards, Vincent
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Re: XCOR Lynx Flight Simulation for Project PoSSUM

Postby curt » Tue Jan 21, 2014 4:34 am

Hi Dr. Reimuller,

It sounds like you are involved in a fascinating project! I've sent you a direct email, but if any one else here cares to reply as well, by all means feel free.

Best regards,

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Location: Minneapolis, MN

Re: XCOR Lynx Flight Simulation for Project PoSSUM

Postby Hooray » Tue Jan 21, 2014 9:42 am

I'd suggest to also add this to the FlightGear newsletter, and post it on the devel list, too - and ideally also post it on the website.
Please don't send support requests by PM, instead post your questions on the forum so that all users can contribute and benefit
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Re: XCOR Lynx Flight Simulation for Project PoSSUM

Postby Thorsten » Thu Jan 30, 2014 9:24 am

I've just pushed support for generating noctilucent clouds using Advanced Weather / ALS to GIT. Since I suspect that the pictures of the clouds available are taken with long exposure time, I have assumed that they would be fairly faint with bare eye. Making them brighter is easy, I think I can pretty much accomodate any additional info on how they look when in the shader code.

The clouds appear at ~270.000 ft altitude, and they're only visible while the air column below is in shade but the cloud itself is in light, i.e. shortly after nightfall or before daybreak.

Here's a pic of the patch for different altitudes (the second from mid-altitude of 50 km shows nicely how the shadow of the planet darkens the air column below.


To use the clouds (requires current GIT):

* set the property /environment/create-noctilucent-clouds to true (either commandline or property browser will do)
* start any weather scenario of Advanced Weather
-> a single patch of clouds will be generated above you, as above, they're not visible under most lighting conditions, also they may be hidden by haze layers in the low atmosphere

Also, the cloud patch is *very* large and far away, so we need to make sure that it's seen

* using the property browser, set /sim/rendering/camera-group/zfar to 250000 (or more) - this will not affect terrain visibility
* using the Advanced Weather options menu, set max. visibility to 250 km
-> this will open up visibility of the terrain just as well and may be crippling for low memory machines, it sets zfar automatically now

The cloud layer looks deceptively close, but it really isn't - nothing but an X-15 or the Vostok-1 will actually get you there. Or the ufo of course...

At some altitudes, looking away from the sun, I'm getting freak graphical artefacts from the skydome shader, looking like rounding errors or so. Can anyone else confirm these?
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Re: XCOR Lynx Flight Simulation for Project PoSSUM

Postby jreimuller » Mon Feb 03, 2014 11:42 pm

These images look very good, and it looks like the clouds contain many of the micro-features that we would be most interested in studying: bands, billows, areas of instability. The ideal time to launch would probably be from 1-3 hours before or after local midnight (where the sun is north, but not exactly due-north) and we can verify the cloud presence from the ground and then get predominantly forward scattering off of the clouds once in flight.

I'm in discussion with a group that has developed the Viper full motion simulator that uses Flight Gear, and this can make a very good complement to the simulation.

And many thanks to everyone that is taking part with this! Its wonderful to see so much enthusiasm and exceptional talent as part of this!

-Jason Reimuller
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