Speeding Up Space Communications

The first node of the Interplanetary Internet, a robust Internet-style communications network for outer space, has finally made its way to the International Space Station (ISS), and has already sent back its first set of data–images of crystals formed by metal salts in free-fall.

The system is a new communications protocol intended to speed up the delivery of data from spacecraft to earth. Robotic equipment has been flying to space since the 1960s, communicating with earth by using either point-to-point radio links or the Deep Space Network (DSN), built by NASA in 1964. While these communication schemes have been efficient, they’re like using dial-up AOL to access the Web when better technology is available. And as the number and complexity of missions increases, it will only become more problematic. So ten years ago Vint Cerf, who designed the networking protocols that launched the Internet, joined a team at NASA’s Jet Propulsion Laboratory and built the Interplanetary Internet.

The system is modeled after the terrestrial network, but instead of using its standards called the TCP/IP protocol suite–packet switching and store-and-forward methods–the Interplanetary Internet uses delay- and disruption-tolerant networking (DTN)–routing information through hosts that hold on to it until a communications link can be established. “The team set out to develop a suite of protocols that would allow us to have the kind of network flexibility in space that we have on Earth,” said Cerf, also Google’s vice president and chief internet evangelist, in this interview with me, in which he also discussed, in-depth, the technical details of the system.

The system was first tested for a month in November 2008–a spacecraft 20 million miles away from Earth sent dozens of images back. Now that the first node is permanently on ISS, I think astronauts and robotic spacecraft will finally have the opportunity to send more data with fewer constraints–communications won’t be blocked when the ISS travels behind a planet or experiences power outages. And since the system holds onto information at one node until it finds the next node in the chain, energy won’t be wasted by continually trying to communicate until everything is sent, such as the case with Earth Internet protocols. In addition, the new system could alleviate traffic to the DSN. Thus, we should get more information from space faster, enhancing our knowledge of what’s out there. Also it provides an avenue for astronauts to communicate more frequently with the public.

A second Interplanetary Internet node will be sent to the station later this year.