Interplanetary Internet

has successfully tested a deep space communications network it's calling the Interplanetary Internet.

Working as part of a NASA-wide team, engineers from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California used Disruption-Tolerant Networking, or DTN, to transmit dozens of space images to and from a NASA science spacecraft located about 20 million miles from Earth.

NASA and Vint Cerf, a vice president at Google, joined forces 10 years ago to develop the DTN software protocol that sends information using a method that differs radically from the normal internet's transmission-control protocol/internet protocol, or TCP/IP, communication suite, which Cerf co-designed.

Any communications protocol used in space must be robust to withstand delays, disruptions and disconnections. Glitches can happen when a spacecraft moves behind a planet, or when solar storms and long communication delays occur. The delay in sending or receiving data from Mars, for example, takes between three-and-a-half to 20 minutes at the speed of light.

For that reason, the DTN does not assume a continuous end-to-end connection like TCP/IP. In its design, if a destination path cannot be found, the data packets are not discarded. Instead, each network node keeps the information until it can communicate safely with another node. This store-and-forward method means information does not get lost when no immediate path to the destination exists. Eventually, the information is delivered to the end user.