Explorations: Landing on the Moon

The Orbiter Space Simulator: An Appreciation

Apollo 11 CSM on the trip back from the moon

This appreciation of Orbiter was written in 2006, but remains up-to-date as of December 2009. Ironically, I discovered Orbiter just as development slowed down. Over the next three years, Orbiter did not release any new versions, and NASSP released a progression of betas. You'll see that, even in 2006, I had to search around a bit, as many people had dropped out of the community and their information had grown out of date. It's hard to keep a community-driven project going.


The first decade of the twenty-first century is an exciting time to be a space nut. Not only is the International Space Station whizzing overhead constantly, but China has launched men into orbit, and private spaceflight is finally getting off the ground. But even this frenzy of activity does not begin to approach the excitement of the 1960s, when the Apollo program launched men to the moon. Fortunately, we can relive and reenact the heady days of the Space Race through another technological wonder — the computer.

In 1995, director-producer Ron Howard introduced a whole new generation to the excitement of the Apollo program with his box-office smash Apollo 13, starring self-avowed space nut Tom Hanks as Commander Jim Lovell. Avoiding the use of NASA stock footage, the effects crew at Digital Domain used nascent digital techniques -- Computer-Generated Imagery (CGI) and computer compositing -- to enhance traditional effects techniques of photographing spacecraft miniatures.

Three years later, Tom Hanks convinced HBO to invest in an excellent 12-hour miniseries on the Apollo programs, From the Earth to the Moon, which received a larger total budget than the earlier motion picture. Digital effects were used more extensively on the miniseries, which combined CGI effects with color-corrected stock footage for a docudrama look. Besides, Moore's Law meant that four times as much computer power had become available since the film.

Well, time continues marching on, and the expensive Silicon Graphics workstations of yesteryear now pale in comparison with the computers sitting on your desk. In 2000, Dr. Martin Schweiger of University College London began work on a 3D space simulator called Orbiter. Over the years, he has maintained it, added features, and most importantly, developed an architecture that allows for community-contributed add-ons. In fact, even the core feature of sound effects — launch rumbles, spacecraft ambient noise, communications chatter — is implemented as an add-on, written by Orbiter enthusiast Dan Steph.

Orbiter screenshot. T+0:09:20. The expended Saturn V second stage separates. The small jets of flame are the ullage thrusters.

The beauty of the simulator is that it provides a much deeper understanding and appreciation of the technology that got Apollo to the moon. I've been a space nut since I was six years old, when my father bought me a copy of The Omni Space Almanac. I've read about the technology in numerous books and articles, but no matter how exciting those descriptions were, they nevertheless remained words on paper. Orbiter, in contrast, provides the visceral thrill of being able to (virtually) flip the switches and push the keys on the DSKY, then actually see them take effect on the spacecraft. Spaceflight concepts that are usually difficult to understand become second-nature after they've been tried out in the simulator. Perplexing orbital mechanics that had previously been brain-twisters of 3D geometry now become intuitively obvious.

Microsoft Flight Simulator virtually buckles you in the pilot seat without having to shell out $100 an hour to rent a Cessna. Orbiter has taken the trail blazed by the long-since discontinued Microsoft Space Simulator (1994), and paved it into a multi-lane expressway. With Orbiter and its add-ons, you can (virtually) strap yourself into the astronaut's couch for $20 million less than it costs to fly along on a Soyuz mission to the International Space Station. In some ways, it's better. You can get a flying license and actually control a plane, but even the billionaire space tourists are mostly just sightseeing. This is truly a geeky thrill that will not be available for decades to come.