The
Internet has entered the final frontier.
NASA has
successfully tested the first deep space communications
network modeled on the Internet, using it to transmit images to and from a
spacecraft 20 million miles from Earth, it was announced on Tuesday.
"This
is the first step in creating a totally new space communications capability, an
interplanetary Internet," said Adrian Hooke, leader of the team that
performed the feat and manager of space-networking architecture, technology and
standards at NASA Headquarters in Washington, D.C.
NASA and
Vint Cerf, a vice president at Google,
in Mountain View, Calif., who is often called the father of the Internet,
partnered 10 years ago to develop the software protocol used for space transmissions,
called Disruption-Tolerant Networking, or DTN. The DTN sends information using
a method that differs from the terrestrial Internet's Transmission-Control
Protocol/Internet Protocol (TCP/IP) communication suite, which Cerf
co-designed.
The
Interplanetary Internet must be robust enough to withstand delays, disruptions
and disconnections in space. Glitches can happen when a spacecraft moves behind
a planet, or when solar storms and long communication delays occur. For
instance, the delay in sending or receiving data from Mars takes between
three-and-a-half to 20 minutes, even at the speed
of light.
If a
disruption occurs in the pathway along which the information travels, each node
in the network will hang on to its information until it's safe to communicate,
unlike our Internet on Earth, which just discards
the data packets.
The new
network could ease communication with distant spacecraft and enable new kinds
of space missions.
"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 NASA's Jet Propulsion Laboratory in Pasadena, Calif. "With
standardized DTN, this can all be done automatically."
The DTN was
tested during a month-long experiment in October, using NASA's Epoxi spacecraft
(currently on a mission to encounter Comet Hartley 2 in two years) and nine
other "nodes," all on the ground at JPL.
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