Space probes could talk faster with light

PASADENA, Calif., July 25 (UPI) -- NASA is in the process of updating its deep space communications network, but a team of researchers has urged the agency to abandon radio wave technology and look to develop a new system based on near-infrared lasers.

"It's pretty obvious that in a few years the Deep Space Network won't be able to handle the loads that are going to be put on it," Alex Harwitt, a researcher and developer at Transparent Networks in Milpitas, Calif., said in an interview with United Press International.


Harwitt, co-author of a paper appearing in the July 26 issue of the journal Science, and his colleagues estimate that a new laser-based communications network linking far-flying spacecraft to ground control teams on Earth would cost in the neighborhood of $400 million for three receiving stations and development of space-based laser technology for satellites.

NASA as well as the Japanese and European space agencies have tested lasers in space successfully.

"Twenty years ago there was not the comfort level in laser technology that there is today," said James Lesh, who oversees technology programs for NASA's Deep Space Network at the Jet Propulsion Laboratory in Pasadena, Calif.


Not only would a laser-based system greatly expand the network's ability to handle large volumes of data, but the lasers themselves also could be used as scientific instruments to probe, for example, planetary atmospheres.

"Light science -- using lasers to probe things -- is a whole new area that has yet to be explored," said Lesh.

NASA has made several upgrades to its deep space communications network and is in the process of transitioning from X-band to Ka-band, an improvement that is expected to increase the capability of the network by a factor of four or five, said Lesh. Switching from radio waves to optical beams, however, would give scientists so much more capability to return data from their instruments that it would cause a paradigm shift, he added.

For example, although several planetary probes have flown with high-resolution cameras, only a fraction of mapping imagery can be returned to Earth because of limitations of the Deep Space Network, Lesh said.

The demand on the communications system is expected to roughly double over the next decade or so as NASA contracts for more but less expensive space science missions. All the probes, however, still need to relay their data back to Earth and receive commands for future operations.


"The Deep Space Network is definitely a limiting factor in science," said Lesh.

Harwitt and his colleagues said if work began now on a near-infrared telemetry system, it would be ready to support space missions in 10 to 15 years.

"A concerted action will be required to prevent a crisis in the form of a data transmission bottleneck," the researchers said.

(Reported by Irene Brown, UPI Science News, in Cape Canaveral, Fla.)

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