(AFP) – Nov 18, 2008
WASHINGTON (AFP) — The US space agency NASA said it successfuly conducted a first test of a deep space communications network modeled on the Internet.
"This is the first step in creating a totally new space communications capability, an interplanetary Internet," Adrian Hooke, NASA's manager of space-networking architecture, technology and standards, said in a statement.
The US space agency said Jet Propulsion Laboratory engineers used software called Disruption-Tolerant Networking, or DTN, to transmit dozens of space images to and from a NASA spacecraft some 20 million miles (32.4 million kilometers) from Earth.
NASA said the software protocol, which must be able to withstand delays, disruptions and disconnections in space, was designed in partnership with Vint Cerf, a vice president at Internet search giant Google.
DTN sends information using a method that differs from the normal Internet's Transmission-Control Protocol/Internet Protocol, or TCP/IP, communication suite, which Cerf co-designed, NASA said.
Unlike TCP/IP, DTN does not assume a continuous end-to-end connection, NASA said, noting that glitches can happen when a spacecraft moves behind a planet, or when solar storms and long communication delays occur.
It said the delay, for example, in sending or receiving data from Mars takes between three-and-a-half minutes and 20 minutes at the speed of light.
NASA said that if a destination path cannot be found, data packets are not discarded but kept by each network node until it can communicate safely with another node.
Eventually, it said, the information is delivered to the end user.
"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 the Jet Propulsion Laboratory in Pasadena, California.
"With standardized DTN, this can all be done automatically."
NASA said engineers had begun a month-long series of DTN demonstrations in October using NASA's Epoxi spacecraft, which is on a mission to encounter Comet Hartley 2 in two years, as a Mars data-relay orbiter.
It said there are 10 nodes in the early interplanetary network -- the Epoxi spacecraft itself and nine on the ground at the Jet Propulsion Laboratory simulating Mars landers, orbiters and ground mission-operations centers.
NASA said a test of DTN software loaded on board the International Space Station would begin next summer.
It said an "Interplanetary Internet" could enable many new types of space missions including complex flights involving multiple spacecraft and ensure reliable communications for astronauts on the the moon.
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