
Orbiter Space Flight Simulator 2016 Edition - based2
http://orbit.medphys.ucl.ac.uk/
======
eddieh
This looks really awesome. Too bad it isn't open source. Would love to see it
running on macOS & Linux. It would probably be a blast to port.

~~~
qwertyuiop924
We Mac and Linux users play KSP instead. And then we drown our sadness by
watching Scott Manley exploit glitches.

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exDM69
Very nice to see an update to Orbiter after a long time.

I'd really like to see it open sourced, but I guess that isn't happening.
Setting it up properly is a bit of a mess right now, you need a 3rd party
graphics engine called D3D9Client for that (or stick to using the old D3D7
engine). A lot of useful functionality is also 3rd party plugins you have to
install from a variety of sites. You _can_ play it right out of the box, but
it's much better with 3rd party additions. If it was open source, perhaps it
would be a bit easier to manage.

... now to toot my own horn for a bit:

I've also been working on space simulation and orbital mechanics projects for
fun (and some university classes earlier).

If there's anyone here who likes Orbiter and/or Kerbal Space Program and is
interested in related programming projects, get in touch (in HN comments or
IRC/freenode for my HN username).

Here's a quick screenshot of what I'm working on right now:
[http://ctrlv.in/884711](http://ctrlv.in/884711) (just started doing some 3d
visualization earlier this week)

And here's a two body orbital mechanics library I have been working on for a
few years:
[https://github.com/rikusalminen/twobody](https://github.com/rikusalminen/twobody)
(it should have everything you need to write your own KSP clone - look around
in the different branches)

~~~
musgravepeter
I'm a big fan of orbiting problems. There are some cool references on your
gitlab - I'll need to dig through them sometime.

Now some of my "tooting":

I did a quick JS Kepler evolver
([http://nbodyphysics.com/blog/2016/05/29/planetary-orbits-
in-...](http://nbodyphysics.com/blog/2016/05/29/planetary-orbits-in-
javascript/)) and some very funky regularizing integration for the three body
problem
([http://nbodyphysics.com/blog/threebodyv2/](http://nbodyphysics.com/blog/threebodyv2/)).

Lots more side projects queued up - latest is a Unity Asset, Gravity Engine.

Under "hugely ambitious" is trying to grok
[http://www.cds.caltech.edu/~marsden/volume/missiondesign/KoL...](http://www.cds.caltech.edu/~marsden/volume/missiondesign/KoLoMaRo_DMissionBook_2011-04-25.pdf)
and do real three-body trajectories.

~~~
exDM69
Good stuff and interesting projects. I spent a while going through your blog
posts and other stuff.

Do you mind if I drop you an email to exchange some ideas?

Your Kepler's equation solver looks like a pretty standard textbook Newton
iteration. I'm sure you're aware of its shortcomings, look at libtwobody for a
more advanced solver (Laguerre-Conway) and the bibliography for the papers
describing it. There's also a universal variable solver which doesn't have
issues for near-parabolic orbits and handles elliptic/parabolic/hyperbolic
orbits with no special cases.

I've also got an interest in 3-body and n-body stuff but so far I've
concentrated on the two body mechanics and dabbled a bit with simulating
rocket launches.

Your Unity Asset looks pretty interesting. Has it been popular? I've also
considered making (code) assets for Unity, so please do share any experiences
you've got.

~~~
musgravepeter
The Kepler equation solver is the standard Newton iteration, which is ok until
e gets larger. The actual N-body simulator in gravity engine allows for better
orbits and the integrator is configurable (Hermite, Leapfrog) and easy to
extend. Colwells book has LOTS on this subject too
([https://www.willbell.com/MATH/mc12.htm](https://www.willbell.com/MATH/mc12.htm))

There are about 20 GE users so far, so it seems somewhat "niche". Offering an
asset forces me to think a lot more about usability and documentation. I have
recently added support for any solar system object and real world units - with
tunable scaling. Not things I would have done if I was not making it an Asset.
It's gratifying to get some uptake and the people who use it seem to like it.

If you like Three Body stuff, checkout my iOS/Android three body app. LOTS of
solutions to explore. ([https://itunes.apple.com/us/app/threebody-
lite/id951920756?m...](https://itunes.apple.com/us/app/threebody-
lite/id951920756?mt=8/) or
[https://play.google.com/store/apps/details?id=com.nbodyphysi...](https://play.google.com/store/apps/details?id=com.nbodyphysics.threebodylite&hl=en))

~~~
exDM69
Thanks for all the good links.

Get in touch if you want to chat about projects.

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chakalakasp
I've wasted many hours on orbiter - understand that it is very much like
Kerbal, only much less intuitive and forgiving, and with no training wheels.
Like Kerbal, playing this legitimately helps you to understand orbital
mechanics. It's fun in the same way that a flight simulator is fun, only now
you're going to space instead of the sky.

~~~
TeMPOraL
Depends on your definition of forgiveness - it's true the flying part is
harder in Orbiter, but last time I checked it didn't reward even most trivial
mistakes with turning you into a fireball, like KSP does.

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anotheryou
Also recommended: [http://en.spaceengine.org/](http://en.spaceengine.org/) (no
real flying, but plenty of pretty planets)

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ptrincr
I spent so much time on this. Learning how to use the various MFD's, trying to
plot a course from Earth -> Moon -> Mars, with a slingshot around the Earth
after refueling.... difficult but addictive.

Then there was the UCGO mod. Just take a look at this breathtaking video to
see what that gave you:
[https://www.youtube.com/watch?v=MQBiX8STHUk](https://www.youtube.com/watch?v=MQBiX8STHUk)

If you liked Kerbal, this is the next step up.

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mdorazio
Kerbal Space Program has forever ruined all other space simulators for me.
Orbiter is great, but there's just so much more to do in KSP and you can make
it as fun or as challenging as you want.

~~~
exDM69
Do you use some mods for KSP? It's a great game but the physics simulation
(out of the box) is rather rudimentary compared to Orbiter.

I know there's a n-body physics mod called Principia but I have not tried it,
so I don't know how much it changes the gameplay.

~~~
qwertyuiop924
FAR and KIDS are semi-standard for KSP realism. I don't know if they play
nicely with Principia, though.

