The Internet Goes Interplanetary

Future space explorers, both robotic and human, now have a new way to communicate with each other – by the Internet. While email has been used for some time from low Earth orbit, and astronauts have even posted to Facebook and Twitter, the actual connections utilize the standard radio point-to-point links that have been used all along.

For modern fleets exploring space, which include far-flung satellites, spacecraft, rovers and maybe bases someday, this is insufficient, just as the traditional Internet would be. Point-to-point creates a single line of communication between two stations, such as ground control and say, a satellite circling Mars. Another such direct connection can create a line of communication between the ground and a rover on the planet. But the rover can’t communicate directly with the satellite. The network only goes through ground control.

An “Internet-like” connection changes all that. Then, everything could talk with everything else – or it could except for the distance. The problem with installing the Net on such widely separated systems is that unlike communications in science fiction, radio waves move at the speed of light.

The Enterprise can call Starfleet Command every time they run into the Klingons, but real spaceships anywhere beyond the Earth-Moon system will not find it so easy. While it’s only 1.25 seconds for a message to get from Earth to the Moon, to Mars it ranges from over 4 minutes to over 20. And that’s just one way. There are also significant packet losses to worry about over cosmic distances plus security issues too – lack of instantaneous communications makes current encryption techniguqes much more difficult.

Most Internet protocols are impatient; really, really impatient. They will resend packets after a timeout delay of mere milliseconds. So to get around this, engineers have devised a new Internet Protocol. DTN, for Delay (or Disruption) Tolerant Networking allows for extreme delays in communications by having the data wait at a communication node for however long is necessary. It works with a new Bundle Protocol, BP, which works like the Earth-bound Internet Protocol that runs the Net.

BP lumps packets together in such a way as to limit loss and necessity of retransmitting. Without these two new protocols working together, communications might just resemble two deaf people shouting at each other across a room. “What?” “What did you say?” “Say again….”

The Net went interplanetary on October 23 of this year. NASA and ESA, the European Space Agency successfully tested DTN. Astronaut Sunita Williams aboard the International Space Station sent commands to control a small robot on Earth made from Legos.

It may seem trivial but from such small experiments, the Internet was born. However, even if an Interplanetary Internet is created, the laws of physics still apply. Until we reach the level of Star Trek, there won’t be any live Skype chats between Mars colonies and the Earth.

But that might not be such a bad thing after all. The whole idea of colonizing space, after all, is to get away from the motherworld. Would the United States have ever come into being if colonial governors could email the Prime Minister?

This entry was posted in How the Net Works, Interesting Items and tagged , , , , , . Bookmark the permalink.

Comments are closed.