Space

NASA to demonstrate laser beam communications system

NASA to demonstrate laser beam communications system
Conceptual image of the Laser Communications Relay Demonstration that is designed to increase the data rate of space communications (Image: NASA)
Conceptual image of the Laser Communications Relay Demonstration that is designed to increase the data rate of space communications (Image: NASA)
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The LCRD would network with multiple ground stations in the event of bad weather (Image: NASA)
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The LCRD would network with multiple ground stations in the event of bad weather (Image: NASA)
Conceptual image of the Laser Communications Relay Demonstration that is designed to increase the data rate of space communications (Image: NASA)
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Conceptual image of the Laser Communications Relay Demonstration that is designed to increase the data rate of space communications (Image: NASA)

Since the dawn of the space age, NASA has been relying on radio communications technology to send and receive data to and from spacecraft. Although it has developed higher data-rate radio frequency systems, data-compression, and other techniques to boost the amount of data that its current RF systems can handle, they can't keep pace with the projected data needs of advanced instruments and further human exploration. To break this bottleneck, NASA is turning to optical communications technology that would use lasers to increase data rates over existing systems by anywhere from 10 to 100 times.

NASA's current legacy radio-based network includes a fleet of tracking and data relay satellites and a network of ground stations. At the current limit of 6 Mbps for the Mars Reconnaissance Orbiter (MRO), NASA says it currently takes 90 minutes to transmit a single HiRISE high-resolution image from Mars back to Earth. However, the new optical communications system would reduce the transmission time down to just five minutes and even allow streaming of high definition video from distances beyond the Moon.

The Laser Communications Relay Demonstration (LCRD) is designed to enable NASA, other governmental agencies and the commercial space industry to undertake future, complex missions by providing significantly higher data rates for approximately the same mass, power, and volume as a comparable RF system.

NASA says laser-based space communications will enable missions to use bandwidth-hungry instruments, such as hyperspectral imagers, synthetic aperture radar (SAR), and other instruments with high definition in spectral, spatial, or temporal modes. Laser communication will also make it possible to establish a "virtual presence" at a remote planet or other solar system body.

The LCRD is expected to fly as a hosted payload on a commercial communications satellite developed by Space Systems/Loral, of Palo Alto, California. The experimental payload will include telescopes, lasers, mirrors, detectors, a pointing and tracking system, control electronics, and two different types of modems; one ideal for communicating with deep space missions or tiny, low-power smallsats operating in low-Earth orbit, and another that can handle much higher data rates, particularly from Earth-orbiting spacecraft, including the International Space Station.

A team at the NASA Goddard Space Flight Center in Greenbelt, Maryland, which is leading the development of the system, will encode digital data and transmit the information via laser light from specially equipped ground stations to the experimental payload on the commercial communications satellite. Once the payload receives the data, it would then relay it back to the ground stations that are now scheduled to operate in Hawaii and Southern California.

The LCRD would network with multiple ground stations in the event of bad weather (Image: NASA)
The LCRD would network with multiple ground stations in the event of bad weather (Image: NASA)

The multiple ground stations are important, as the optical system requires a clear line of sight between the transmitter and receiver. So if bad weather prevents a signal from being sent or received at one location, the network could hand things over to one of the other ground stations or store it for later transmission.

"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," said LCRD Principal Investigator Dave Israel. "What we're trying to do is get ahead of the curve. 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," Israel added. "With the higher-speed modem type, future systems could support data rates of tens of gigabits per second," he said.

NASA plans to demonstrate the LCRD system in 2016, with the demonstration expected to run two to three years. It is one of three proposals NASA has selected as Technology Demonstration Missions because of their potential to provide tangible, near-term products and have high-impact of NASA's future space exploration and science missions.

The other two proposals selected were a Deep Space Atomic Clock designed to provide the unprecedented stability needed for next-generation deep space navigation and radio science and an in-space demonstration of a mission-capable solar sail to enable propellantless in-space navigation for missions such as advanced geostorm warning, economic orbital debris removal, and deep space exploration. More on these later.

8 comments
8 comments
MrGadget
When all satellites are converted to this system, there will be an increase in temporary blindness in airline pilots.
voluntaryist
\"...the commercial communications satellite.\" What is this? A privately owned satellite working with NASA? Is public money helping a private company develop? Why is no private company doing this research alone?
Derek Howe
All three of those proposals sounds good, But I think this one deserves the funding. 90 minutes for 1 hi-res picture is brutal...I would go nuts waiting.
WE HAVE TOUCHDOWN ON THE RED PLANET! AND NOW, THE BEAUTIFUL HD PICTURES! WAIT FOR IT....WAIT FOR IT......JUST ONE MORE HOUR TO GO........!
Tro Den
I for one welcome our new Satellite Lazer Overlords...
Richard Belihomji
@volutaryist
I think its the other way around, actually. NASA hasn\'t the funding to send their own satellite up so they\'re piggy-backing on a commercial one. Very sad, but quite common.
TogetherinParis
This technology (thank-you Russia) has been around since the 1970\'s. I\'m a little surprised that NASA has been so tardy to incorporate this tech. In fact, I\'m also shocked that our military has not utilized this. Of course, I\'m easily shocked.
Mike Kling
This points out why our search for ETs with radio telescopes has always been a waste of time. In any civilization there is probably only a very short period where it would rely on regular radio waves for communication.
mike65401
@TOGETHERINPARIS What makes you think our military isn\'t utilizing this technology already? Just because the public doesn\'t know doesn\'t mean there isn\'t classified systems.