Lasers may 'shine' spacecraft data to Earth
ANGLO-AUSTRALIAN OBSERVATORY NEWS RELEASE
Posted: July 29, 2002

Lasers and telescopes could replace radio transmitters on satellites in ten years, suggests a paper in the current issue of Science.

They'd fix a worsening bottleneck in getting data back from satellites and spacecraft, say authors Joss Bland-Hawthorn (Anglo-Australian Observatory), Alex Harwit (Transparent Networks), and Martin Harwit (Cornell University).

Art
An artist's concept of a telescope with laser transmitter in Mars orbit. Credit: Anglo-Australian Observatory
 
The problem is bandwidth -- the size of the data "pipe". Currently data is sent to Earth as radio waves. The higher the carrier frequency, the greater the bandwidth, and the faster the data can be sent.

But the sky's the limit -- literally. Gases in Earth's atmosphere absorb radio frequencies above 300 GHz.

Today's spacecraft do "onboard processing", choosing some data to send and discarding the rest. But in the long term a different solution is needed.

"Detector chips for astronomy now have millions of pixels," said Dr Bland-Hawthorn. "Hubble's successor, the Next Generation Space Telescope, will carry a set of these. Future astronomy missions will have detectors with a thousand times more pixels than today's."

To download all their data these satellites would have to transmit at 100 gigabits a second. But current systems are hundreds of times too slow.

Earth's atmosphere lets through near-infrared radiation. A thousand times higher in frequency than radio waves, it can carry data at a far higher rate. So why not use infrared lasers to shine down the data? ask the Science paper's authors.

A wavelength around 1 micrometre would be used. "Most of the necessary technologies have already been developed for optical fibre communications," said Dr Alex Harwit.

Ten-metre optical telescopes on mountaintops would receive the signals. Cloud blocks near-infrared radiation. But some mountaintop sites have up to 350 cloudless days a year. "If you have a number of receiving stations, there's almost no chance they'd all be clouded out," said Dr Martin Harwit.

Because the narrow laser beam would target the signal better than a radio beam, less energy would go astray, and onboard power consumption would be slashed. A laser would need only a fraction of the power of today's transmitters.

Last year the European Space Agency tested a laser link between two satellites, SPOT-4 and Artemis. NASA too is exploring the option of laser communications.

The technique would work well for spacecraft orbiting Mars, 400 million kilometres away, according to Dr Bland-Hawthorn.

The Science paper calls for "energetic action" from the scientific community to head off the looming crisis in data transmission.

"Space missions flying ten years from now will collect huge amounts of data," said Dr Alex Harwit. "We'd like to see work start now on a laser telemetry system that can handle it."

"Astronomers, weather forecasters, resource managers -- anybody who uses a satellite or spacecraft would benefit from this new technology," said Dr Andrew McGrath of the Anglo-Australian Observatory.

Hubble
Astronomy Now presents Hubble: the space telescope's view of the cosmos. A collection of the best images from the world’s premier space observatory.
 U.S. STORE
 U.K. & WORLDWIDE STORE
Apollo 15 DVD - special price
For a limited time only, preorder your Apollo 15 DVDs at a special discount price. Two- and six-disc editions of this unique DVD are coming soon.
 U.S. STORE
 U.K. & WORLDWIDE STORE

Apollo 11
Apollo 11 - The NASA Mission Reports Vol. 3 is the first comprehensive study of man's first mission to another world is revealed in all of its startling complexity. Includes DVD!
 U.S. STORE
 WORLDWIDE STORE

John Glenn Mission Patch

Free shipping to U.S. addresses!

The historic first orbital flight by an American is marked by this commemorative patch for John Glenn and Friendship 7.
 U.S. STORE
 WORLDWIDE STORE

Final Shuttle Mission Patch

Free shipping to U.S. addresses!

The crew emblem for the final space shuttle mission is available in our store. Get this piece of history!
 U.S. STORE
 WORLDWIDE STORE

Celebrate the shuttle program

Free shipping to U.S. addresses!

This special commemorative patch marks the retirement of NASA's Space Shuttle Program. Available in our store!
 U.S. STORE
 WORLDWIDE STORE

Anniversary Shuttle Patch

Free shipping to U.S. addresses!

This embroidered patch commemorates the 30th anniversary of the Space Shuttle Program. The design features the space shuttle Columbia's historic maiden flight of April 12, 1981.
 U.S. STORE
 WORLDWIDE STORE

Mercury anniversary

Free shipping to U.S. addresses!


Celebrate the 50th anniversary of Alan Shephard's historic Mercury mission with this collectors' item, the official commemorative embroidered patch.
 U.S. STORE
 WORLDWIDE STORE

Fallen Heroes Patch Collection
The official patches from Apollo 1, the shuttle Challenger and Columbia crews are available in the store.
 U.S. STORE
 WORLDWIDE STORE

An insider's view of how Apollo flight controllers operated and just what they faced when events were crucial.
 Choose your store:
U.S.

Soviet Space
For the first time ever available in the West. Rocket & Space Corporation Energia: a complete pictorial history of the Soviet/Russian Space Program from 1946 to the present day all in full color. Available from our store.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Viking patch
This embroidered mission patch celebrates NASA's Viking Project which reached the Red Planet in 1976.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Apollo 7 DVD
For 11 days the crew of Apollo 7 fought colds while they put the Apollo spacecraft through a workout, establishing confidence in the machine what would lead directly to the bold decision to send Apollo 8 to the moon just 2 months later.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Gemini 12
Gemini 12: The NASA Mission Reports covers the voyage of James Lovell and Buzz Aldrin that capped the Gemini program's efforts to prove the technologies and techniques that would be needed for the Apollo Moon landings. Includes CD-ROM.
 Choose your store:
U.S. - U.K. - E.U. - Worldwide

Station Calendar
NEW! This beautiful 12" by 12" wall calendar features stunning images of the International Space Station and of the people, equipment, and space craft associated with it, as it takes shape day by day in orbit high above the Earth.
 U.S. STORE
 U.K. & WORLDWIDE STORE

Get e-mail updates
Sign up for our NewsAlert service and have the latest news in astronomy and space e-mailed direct to your desktop (privacy note: your e-mail address will not be used for any other purpose).
Enter your e-mail address:

INDEX | PLUS | NEWS ARCHIVE | LAUNCH SCHEDULE
ASTRONOMY NOW | STORE

ADVERTISE

© 2014 Spaceflight Now Inc.