According to its official site, Orbiter is "a free flight simulator that goes beyond the confines of Earth's atmosphere. Launch the Space Shuttle from Kennedy Space Center to deploy a satellite, rendezvous with the International Space Station or take the futuristic Delta-glider for a tour through the solar system - the choice is yours."

Orbiter takes a simple concept - Microsoft Flight Simulator with spaceships instead of planes - and blows it up into the deepest freeware game you're ever likely to find. The ships in the game each have their own distinct feel, from the classic space shuttle to the airplane-like Delta-glider and the futuristic Shuttle-A. Unlike many space flight games, the emphasis is on flying the ships, rather than interplanetary sightseeing, but there's still a good deal of that.

The physics are amazingly realistic, although it's quite possible to achieve near-light speed. Planetary motion, gravitational effects, free space and atmospheric flight are accurately modelled. Rarely can you spot a flaw in the flight physics. On the other hand, there is no collision detection at all. If you crash into the ground, you will find yourself simply bouncing off. It's less satisfying when you dock perfectly with the ISS knowing that if you make a life-threatening error, you'll fly straight through the station.

The graphics are easily some of the best you'll find in any freeware game, with reflecting water, atmospheric light effects and virtual cockpits. The planets look great from space, but on the ground they're unimpressive at best, being completely textureless, and having no sense of scale, making it hard to know if you're on the ground or not. The game is also completely soundless, but since you spend most of your time in space, there's not to much to whine about when it comes to sound, and if you really do care that much, you can download a mod to alter that by clicking here.

Orbiter can be very confusing to a beginner, and you'll constantly find yourself needing to look at the manual for the umpteenth time. Thankfully, the game comes with plenty of helpful documentation and boasts a well-designed and responsive control scheme that is joystick-compatible. The near-flawless execution of the game completely overshadows the minor niggles that are to be had with it.

Even after you've had your fill of the flight simulation aspect of the game, there's still a surprising number of features left to waste your time with. The game has a planetarium feature that shows constellations. You can also view the planets, ships and space stations in all their high-resolution glory, as well as famous eclipses. You'll be marveling at the coolness of the digital solar system days after you thought you saw everything the game had to offer. The depth of the game matches, if not surpasses, that of Microsoft Flight Simulator. Plus, the game is easy to mod, and the numerous mods available add the Apollo missions, extra-solar travel and countless new spacecraft.
If you have enough interest in games to be reading this right now, you owe it to yourself to at least look at Orbiter.