NASA to demonstrate communications via laser beam

September 23, 2011 By Lori Keesey, JPL/NASA
Conceptual image of LCRD. Credit: NASA

It currently takes 90 minutes to transmit high-resolution images from Mars, but NASA would like to dramatically reduce that time to just minutes. A new optical communications system that NASA plans to demonstrate in 2016 will lead the way and even allow the streaming of high-definition video from distances beyond the Moon.

This dramatically enhanced transmission speed will be demonstrated by the Communications Relay Demonstration (LCRD), one of three projects selected by NASA's Office of the Chief Technologist (OCT) for a trial run. To be developed by a team led by engineers at the NASA Goddard Space Flight Center in Greenbelt, Md., LCRD is expected to fly as a hosted payload on a commercial communications satellite developed by Space Systems/Loral, of Palo Alto, Calif.

"We want to take NASA's communications capabilities to the next level," said LCRD Principal Investigator Dave Israel, who is leading a multi-organizational team that includes NASA's Jet Propulsion Laboratory, Pasadena, Calif. and Lincoln Laboratory at the Massachusetts Institute of Technology, Cambridge, Mass. Although NASA has developed higher data-rate radio frequency systems, data-compression, and other techniques to boost the amount of data that its current systems can handle, the Agency's capabilities will not keep pace with the projected data needs of advanced instruments and future human exploration, Israel added.

"Just as the home Internet user hit the wall with dial-up, is approaching the limit of what its existing communications network can handle," he said.

The solution is to augment NASA's legacy radio-based network, which includes a fleet of tracking and data relay satellites and a network of ground stations, with optical systems, which could increase data rates by anywhere from 10 to 100 times. "This transition will take several years to complete, but the eventual payback will be very large increases in the amount of data we can transmit, both downlink and uplink, especially to distant destinations in the solar system and beyond," said James Reuther, director of OCT's Crosscutting Technology Demonstrations Division.

First Step

The LCRD is the next step in that direction, Israel said, likening the emerging capability to land-based fiber-optic systems, such as Verizon's FiOS network. "In a sense, we're moving FiOS to space."

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 modems. One modem is ideal for communicating with deep space missions or tiny, low-power smallsats operating in low-Earth orbit. The other can handle much higher data rates, particularly from Earth-orbiting spacecraft, including the International Space Station. "With the higher-speed modem type, future systems could support data rates of tens of gigabits per second," Israel said.

Once the payload receives the data, it would then relay it back to ground stations now scheduled to operate in Hawaii and Southern California.

The multiple ground stations are important to demonstrating a fully operational system, Israel said. Cloud cover and turbulent atmospheric conditions impede laser communications, requiring a clear line of sight between the transmitter and receiver. If bad weather prevents a signal from being sent or received at one location, the network could hand over the responsibility to one of the other ground stations or store it for later retransmission.

The demonstration is expected to run two to three years.

Follow-On to LADEE Experiment

The project isn't NASA's first foray into laser communications. Goddard engineers are now developing a laser communications payload for NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE), which the Agency plans to launch in 2013 to characterize the Moon's wisp-thin atmosphere and dust environment. The main goal of the LADEE experiment is proving fundamental concepts of laser-based communications and transferring up to 622 megabits per second, which is about five times the current state-of-the-art from lunar distances.

However, the LADEE payload, called the Lunar Laser Communications Demonstration (LLCD), is equipped with only one modem, the lower-speed model best suited for deep space communications. In addition, LADEE is a short-duration mission. LLCD is expected to operate for only 16 days of the LADEE mission, not enough time to demonstrate a fully operational laser-communications network, Israel said.

"What we're trying to do is get ahead of the curve," Israel said. "We want to get to the point where communications is no longer a constraint on scientists who want to gather more data, but are worried about getting their data back from space."

Explore further: NASA picks three proposals for flight demonstration

Related Stories

NASA picks three proposals for flight demonstration

August 23, 2011

NASA has selected three proposals, including one from NASA's Jet Propulsion Laboratory in Pasadena, Calif., as Technology Demonstration Missions to transform space communications, deep space navigation and in-space propulsion ...

NASA to Test First Mars - Earth Laser Communication Link

August 9, 2004

A NASA–MIT Lincoln Laboratory team will forge the first laser communication link between Mars and Earth. This unique experiment, part of NASA's Vision for Space Exploration, will greatly benefit the transmission of data ...

TDRS spacecraft pass system level reviews

February 22, 2010

NASA's Tracking and Data Relay Satellite (TDRS) K-L program completed its Critical Design Review (CDR) and Production Readiness Review (PRR) in El Segundo, Calif. on Feb. 19.

Recommended for you

Researchers investigate the peculiar radio source IC 1531

October 17, 2018

An international team of researchers has investigated a peculiar extragalactic radio source known as IC 1531. The new study analyzes the nature of IC 1531's high-energy emission, suggesting that the source is a radio galaxy. ...

Astronomers find a cosmic Titan in the early universe

October 17, 2018

An international team of astronomers has discovered a titanic structure in the early Universe, just two billion years after the Big Bang. This galaxy proto-supercluster, nicknamed Hyperion, is the largest and most massive ...

Magnetic fields may be the key to black hole activity

October 17, 2018

Collimated jets provide astronomers with some of the most powerful evidence that a supermassive black hole lurks in the heart of most galaxies. Some of these black holes appear to be active, gobbling up material from their ...

8 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Robert_Wells
1.3 / 5 (4) Sep 23, 2011
this should have been done from the beginning...
pianoman
1 / 5 (10) Sep 23, 2011
SETI COULD UPDATE THEIR SYSTEM WITH LASER RECEIVERS AND THEN HAVE A BETTER CHANCE OF DETECTING 'ET' COMMUNICATION SIGNALS AS OPPOSED TO THE OLD FASHIONED RADIO METHOD. JUST A THOUGHT, THANKS
yyz
5 / 5 (1) Sep 24, 2011
"SETI COULD UPDATE THEIR SYSTEM WITH LASER RECEIVERS AND THEN HAVE A BETTER CHANCE OF DETECTING 'ET' COMMUNICATION SIGNALS..."

Actually, several groups are already pursuing optical SETI projects following earlier attempts that date back to the 1980's: http://en.wikiped...eriments
Mayday
not rated yet Sep 24, 2011
Question: in interstellar travel, at what speed does optical signal attenuation make reception on Earth difficult or impossible?
CHollman82
1.7 / 5 (6) Sep 24, 2011
In optical fiber at 1310/1550nm I know it's roughly 0.3dB/Km due to backscatter... in a true vacuum (which space is not) I don't see any reason for attenuation whatsoever. So I'd say very little... I assume the laser signal would be to an orbiting satellite, which would relay it to the ground via traditional radio technology, as the loss through the atmosphere would be significant if not total.
kaasinees
Sep 24, 2011
This comment has been removed by a moderator.
Pkunk_
2.1 / 5 (7) Sep 24, 2011
The next NASA sat going to mars should have an atomic clock on it. To do some serious measurements of the exact speed of light in a straight line .
pianoman
1.6 / 5 (5) Sep 25, 2011
Magnetic storms can wipe out radio as well.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.