NASA to test laser communications system

Posted by Emma Woollacott

NASA is working on a new communications system that could dramatically cut the time needed to transmit high-resolution images from Mars.

It currently takes 90 minutes to transmit high-resolution images from Mars - but a new optical communications system that NASA plans to demonstrate in 2016 will cut this time to just a few minutes, and even allow the streaming of high-definition video from beyond the Moon.

The Laser Communications Relay Demonstration (LCRD) is expected to fly as a hosted payload on a commercial communications satellite developed by Space Systems/Loral, of Palo Alto, California.

"We want to take NASA's communications capabilities to the next level," says LCRD principal investigator Dave Israel.
"Just as the home internet user hit the wall with dial-up, NASA is approaching the limit of what its existing communications network can handle."

The idea is to augment NASA's legacy radio-based network with optical systems, which could increase data rates by anywhere from 10 to 100 times.

To demonstrate the new capability, the Goddard team will encode digital data and transmit the information via laser light from specially equipped ground stations to an experimental payload hosted on the commercial communications satellite.

The payload will include telescopes, lasers, mirrors, detectors, a pointing and tracking system, control electronics, and two different types of modem. One can communicate with deep space missions or low-power smallsats operating in low-Earth orbit; the other can handle data rates of tens of gigabits per second from Earth-orbiting spacecraft, including the International Space Station.

Once the payload receives the data, it will then relay it back to ground stations in Hawaii and Southern California.

The demonstration is expected to run two to three years.

The project isn't NASA's first foray into laser communications. Goddard engineers are working on a laser communications payload for NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE), due for launch in 2013.

The goal is to prove fundamental concepts of laser-based communications and transfer up to 622 megabits per second, about five times the current best performance from lunar distances.

However, the LADEE payload, the Lunar Laser Communications Demonstration (LLCD), is equipped only with the lower-speed modem best suited for deep space communications. In addition, it's expected to operate for only 16 days -not long enough to demonstrate a fully operational laser-communications network.