Orbiter 2005

While not geared toward observational Astronomy, the freeware spaceflight simulator 'orbiter' has enough scientific realism and visual impressiveness to catch the attention of any astronomy geek. Written for Microsoft's DirectX (and therefore Windows only), the representations of the sun, planets and and moons of the solar system are truly stunning; from the fast-loading, high resolution planetary maps (optional 40mb download) down to subtle, visual effects like specular reflection from liquid & ice, cloud layers (with shadows and high-detail 'micro-texturing') and sophisticated rendering of atmospheric haze.

Behind the eye-candy however is a ruthlessly accurate orbital mechanics and spaceflight simluation, to which the graphical lovelyness is just a back-drop. Realistic and historically accurate 'space-shot' missions such as shuttle launches can be 'played' in real-time (including the Hubble deployment and ISS service missions), but the initial thrill of piloting a virtual shuttle out of the atmosphere and enjoying the view is soon replaced by the sheer frustration of actually getting it into ANY orbit, let alone the right one! This is in not a science fiction game. The margins of error are realistically tiny and the program gives a good sense of contrast about all other things that "aren't exactly rocket science". This program pretty much is. Orbital planes must be aligned, transfer orbits calculated, and burns performed accurately by manual control (with the help of some basic calculation tools of course, no need to know the algebra yourself). The learning curve is steep but this is part of what makes the program so worthwhile. The dry concepts and mathmatics of circularising an orbit, momentum exchange and so-forth get fleshed out with no concessions to point-and-click laziness.

That being said, there's a lot of fun to be had as well with fictional spacecraft such as the included 'delta glider mk4': a more science-fictional spaceplane with goodies like a virtual cockpit, animations and a somewhat implausible thrust-to-weight ratio. With the glider (and other optional addons) realistic atmospheric flight is possible, as is earth orbit and interplanetary travel (get used to the time-accelleration function however). The other planets have their accurate gravity wells and atmospheres and can be landed on or taken off from as well. Most of the solar system is there to be explored (including non-spherical bodies like phobos), once you figure out how to do that!

One further feature bears mention. As with Celestia, the program is basically an engine that generates a simulated universe based on scripts, texture files and 3D models that can be edited and added to by the user. This means that a plethora of custom-made spacecraft, moons, asteroids, surface structures etc can and have been made available by an active online community. While many of the addons are simply the favourite sci-fi spacecraft of the user (or border on the downright geeky), there is a rich body of work which extends the user experience in terms of scientific accuracy as well.

Further contrast to Celestia is instructive, and the two simulations compliment each other well. While Celestia seeks to be a 3D atlas of the known universe (and is far better at that job), its instantly available, God's-eye-view can make the enormity of it all difficult to fathom. Orbiter simulates a tiny fraction of the universe (our solar-system, with an accurate but 'painted on' background of the surrounding stars) but keeps the user firmly, physically embedded in that simluation. There is no 'goto' command to take you to mars: as with real life you're just one (very small) physical object among a whole lot of other physical objects. It's in this sense that this ostensive flight simulator can also be so intellectually rewarding, because the humbling scale of the 'out there' is more or less in your face the whole time.

See the main website for system requirements etc, though give it a try anyway: it runs beautifully on my 1.1Ghz Celeron laptop with 16meg of shared memory for graphics. The program has a launcher application where you can select a wide range of startup 'scenarios' and tweak the visual effects for best performance. See also http://www.orbithangar.com/ for a good database of addons.

Added:  Wednesday, January 26, 2005
Reviewer:  Carl Brusse
Score:
Related Link:  Orbiter Sim
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