NASA successfully tested the first deep space communications network modeled on the Internet and software originally proposed by Vint Cerf more than ten years ago. Engineers from NASA’s Jet Propulsion Laboratory used the Disruption-Tolerant Networking, (DTN) software to transmit dozens of space images to and from a NASA science spacecraft located about 20 million miles from Earth.
The DTN sends information using a store-and-forward method that differs from the normal Internet’s Transmission-Control Protocol/Internet Protocol, or TCP/IP, communication suite, which Cerf co-designed. Unlike TCP/IP on Earth, the DTN does not assume a continuous end-to-end connection. In its design, if a destination path cannot be found, the data packets are not discarded. Instead, each network node keeps the information as long as necessary until it can communicate safely with another node.
“In space today, an operations team must manually schedule each link and generate all the commands to specify which data to send, when to send it, and where to send it,” said Leigh Torgerson, manager of the DTN Experiment Operations Center at JPL. “With standardized DTN, this can all be done automatically.”
Engineers began a month-long series of DTN demonstrations in October. Data were transmitted using NASA’s Deep Space Network in demonstrations occurring twice a week. Engineers use NASA’s Epoxi spacecraft as a Mars data-relay orbiter. Epoxi is on a mission to encounter Comet Hartley 2 in two years. There are 10 nodes on this early interplanetary network. One is the Epoxi spacecraft itself and the other nine, which are on the ground at JPL, simulate Mars landers, orbiters and ground mission-operations centers.
A NASA-wide demonstration using new DTN software loaded on board the International Space Station is scheduled to begin next summer.http://www.NASA.GOV
