Laser-based communication system enables HD video from space probes

Researchers have reported new results from Nasa’s Deep Space Optical Communications (DSOC) technology demonstration project, which develops and tests new advanced laser sources for deep-space optical communication.

Nasa currently relies on radio communication systems to communicate with Mars rovers and probes. However, this incurs average delays of around 20 minutes between the Earth and Mars.

The ability to perform free-space optical communication throughout the solar system would go beyond current capabilities and allow for high-definition images and video as well as a much more responsive way to control probes.

The demonstration system consists of a flight laser transceiver, a ground laser transmitter and a ground laser receiver. The downlink transmitter has been installed on the Psyche spacecraft, which will travel to a unique metal asteroid also called Psyche, which orbits the Sun between Mars and Jupiter.

Psyche is expected to launch in October next year with a mission to explore the origin of planetary cores through its study of the asteroid.

Although free-space optical communications from space to ground have been demonstrated at distances as far away as the moon, extending such links to deep space ranges requires new types of laser transmitters.

The downlink flight laser must have a high photon efficiency while supporting near kilowatt peak power. The uplink laser requires multi-kilowatt average powers with narrow linewidth, good beam quality and low modulation rates.

The laser aboard Psyche passed verification and environmental tests before being integrated into the spacecraft. The uplink laser will also provide a light beacon onto which the flight transceiver can lock.

“Using multiple individual laser sources that propagate through sub-apertures on the telescope’s primary mirror relieves the power requirement from a single source,” said Malcolm. W. Wright, from Nasa’s Jet Propulsion Laboratory. “It also allows atmospheric turbulence mitigation and reduces the power density on the telescope mirrors.”

Now that spacecraft-level testing is complete, the Psyche spacecraft — with the flight laser transceiver aboard — will be integrated into a launch vehicle. The technology demonstration will begin shortly after launch and continue for one year as the spacecraft travels away from Earth and eventually performs a flyby of Mars.