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    Flight Question What is changing Phobos' orbit?

    The bigger fluctuations 295 m/s is an artefact of numercial approximation of the orbit. I'm mot sure about 63 m/s, but NASA uses this ephemerides (like MAR097) in real missions, so it's definitely closer to the real orbit. But it's hard to say how accurate it is in this case. Yes, apparently...
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    Flight Question What is changing Phobos' orbit?

    I've compared the default Phobos ephemeris module with SPICE module in Orbiter. Yes, the default Phobos module has bigger amplitude and speed of apoapsis fluctuations. With SPICE and mar097.bsp kernel it's 1.03 s (~63 m/s), not 1.14 s.
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    Flight Question What is changing Phobos' orbit?

    x - GMAT’s Modified Julian Date (it's one day - 2021-12-01) y - AOP (argument of periapsis in degrees) But I still can't get 295 m/s. Looks like AOP of Phobos is wobbling with speed 0-70 m/s.
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    Flight Question What is changing Phobos' orbit?

    Apoapsis and periapsis of Phobos are not stable and wobbling around some point. There is a graph from GMAT (orbit of Phobos here is based on MAR097 ephemeris file):
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    Flight Question What is changing Phobos' orbit?

    How did you calculate the value 1.14?
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    New Release D3D9Client Development

    Interesting. Using D3D9Client with DXVK ( https://github.com/doitsujin/dxvk ) I get ~20% more fps on Windows 10 than without DXVK. There are some glitches though.
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    Orbiter is now open source

    I can't find source code of some Celbody modules. Ariel, Deimos, Phobos, etc. Are they not open source?
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    News R.I.P. Sir Clive Sinclair

    :( My first home computer was a clone of ZX Spectrum 48K.
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    Project Gmat integration

    Maybe.
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    Project Gmat integration

    It will be difficult to use TransX with GMAT. TransX uses conic sections but this approach doesn't work well with GMAT. Few years ago I added GMAT support to Keithth G's trajectory optimization python script here https://www.orbiter-forum.com/threads/pykep-to-transx-conversion.33685/ and...
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    New Orbiter SVN commit (r.71, Oct 14 2017)

    Are you sure that everything is as usual? Honestly, I don't know what to think.
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    News "Metallic Hydrogen Is Going to Change Everything"

    Yep, no pressure then ;)
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    General Question Lunar Gateway orbit

    I can only do this using GMAT and transfer position/velocity to Orbiter. Yes, but you can tune GMAT propagator parameters close enough to the Orbiter propagator. So it gives good results for Orbiter too. Try this, for example: BEGIN_ENVIRONMENT System Sol Date MJD 60886.5011574074...
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    Question orbits of orbital transfer stations

    Incoming and outgoing trajectories generally are the same. In most cases your have to use tons of extra fuel to get into/from an interplanetary trajectory from/into an equatorial (or any arbitrary) LEO. I doubt that an ideal LEO for the transfer station exists. Your can aproach/departure a...
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    Question orbits of orbital transfer stations

    I don't think so. Try to imagine an inverse problem - targeting a station at zero inclination on your way back from Mars, for examlple.
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    New Orbiter SVN commit (r.71, Oct 14 2017)

    Has Orbiter development been suspended?
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    OHM MPC Database Asteroid Viewer and Exporter v2.0

    boogabooga You can use https://ssd.jpl.nasa.gov/horizons.cgi to get accurate position/velocity of many objects. For example 163348 (2002 NN4): Current Settings Ephemeris Type [change] : VECTORS Target Body [change] : 163348 (2002 NN4) Coordinate Origin [change] : Geocentric [500] Time...
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    Updates Artemis Program Updates & Discussions

    Artemis? Really? https://en.wikipedia.org/wiki/Artemis_(novel)
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    Project Gmat integration

    In Orbiter? There is an example from ScnEditor plugin: oapiGetRelativePos (hV, hRef, &pos); oapiGetRelativeVel (hV, hRef, &vel); // map ecliptic -> equatorial frame if (frm) { MATRIX3 rot; if (frm == 1) oapiGetPlanetObliquityMatrix (hRef, &rot); else oapiGetRotationMatrix...
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    Project Gmat integration

    Really? Sounds like there is a bug in GMAT. It doesn't matter, though. I suspect radiation pressure and atmospheric models in Orbiter and GMAT are very different to include these details into import/export.
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