Orbiter Space Flight Simulator 2016 Edition | Hacker News Reader

Orbiter Space Flight Simulator 2016 Edition

orbit.medphys.ucl.ac.uk

51 pointsbased216 comments

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.

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

I actually just bought Kerbal Space Program, because it's available on Linux, and also supports a vibrant modding community -- include a massive cluster of mods (Realism Overhaul) that turns the Kerbal solar system into a realistic simulation of ours. Add in the Principia mod, which fixes minor glitches in the KSP physics engine, and you're good to go.

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 (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 (it should have everything you need to write your own KSP clone - look around in the different branches)

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-...) and some very funky regularizing integration for the three body problem (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... and do real three-body trajectories.

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.

I've developed a lot of open-source space simulation code and got a few projects in the pipeline. Maybe worth having a chat? My email is in my profile. Anyone interested, feel free to ping me.

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)

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... or https://play.google.com/store/apps/details?id=com.nbodyphysi...)

Thanks for all the good links.

Get in touch if you want to chat about projects.

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.

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.

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

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

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

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.

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.

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

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