The dot earth domain just got a little less exclusive, now that NASA wants to surf the web from outer space.
The agency has completed their first successful test of a deep space network modelled after the Internet, according to a NASA press release.
They are calling it Disruption-Tolerant Networking, or DTN, and the idea, sometimes called Interplanetary Internet, has been around for a while. Vint Cerf, a Google vice-president and co-author of the packet protocols that power the Internet, partnered with NASA a decade ago to work on it, and Wired had one of the first nice discussions of its potential.
It finally appears to be on the road to reality. Since October, engineers at Jet Propulsion Lab in Pasadena, California have been testing the software with a simulated 10-node network. Nine were at JPL. Only one was actually in space: Epoxi, the probe that is on its way to Comet Hartley 2.
The point is to develop an efficient and robust way for missions to move information around the solar system without them having to think about it. It would be a welcome relief to engineers who must create specific uplink and downlink paths for each mission.
The Internet, of course, works by blasting packets off willy-nilly, and those packets find their way to their destination through a wide variety of paths.
It would have to be a little bit different in space, where travel times are substantial, and roadblocks (a planet in the way, a satellite glitch) are more common. The DTN protocol, NASA says, uses a store-and-forward method, where information is kept at a node as long as necessary, until a safe path exists to a node that is closer to the destination.
This would have been useful for, say, the Mars polar lander Phoenix. It typically used Mars Reconnaissance Orbiter as the middleman for communications with Earth. When that link went down, Phoenix had to re-establish a new link altogether – through Mars Odyssey, or Mars Express. With DTN, the information would have gone down those alternate paths naturally.
NASA next plans to test the software with the International Space Station. It will only get better as more spacecraft fill the solar system.
Image: Astronaut William Gregory using a PILOT laptop computer on the STS-067 mission / NASA