Scheduled to embark on its journey alongside the Psyche mission set for liftoff on October 12, NASA's groundbreaking Deep Space Optical Communications (DSOC) experiment is poised to showcase the agency's ability to transmit high-data rates from the outer reaches of our solar system.
Here are five essential aspects to grasp about this cutting-edge technological endeavor:
A Quantum Leap in Data Transmission:
DSOC marks NASA's inaugural venture into harnessing the potential of lasers for data transmission in deep space. Until now, NASA has relied solely on radio waves to communicate with missions beyond the Moon. Much like the transition from traditional telephone lines to fiber optics on Earth, the shift from radio to optical communications promises data rates that dwarf current systems by a factor of 10 to 100. This leap will empower forthcoming human and robotic exploration missions and enhance the capabilities of high-resolution scientific instruments.
A Confluence of Space and Earth:
The DSOC project encompasses both spaceborne and terrestrial components. The DSOC flight laser transceiver is an attachment to NASA's Psyche spacecraft, but Psyche continues to employ traditional radio communications for mission operations. The laser transceiver combines a near-infrared laser transmitter to relay high-rate data to Earth with a photon-counting camera for receiving Earth-transmitted laser signals. Notably, since there is no dedicated infrastructure on Earth for deep space optical communications, two ground telescopes have been retrofitted for DSOC. NASA's Jet Propulsion Laboratory in Southern California will manage operations, while a high-power near-infrared laser transmitter at JPL's Table Mountain facility in California will facilitate the communication process.
Overcoming Unique Challenges:
DSOC faces the formidable task of demonstrating high-data transmission capabilities across distances of up to 240 million miles (390 million kilometers). This range, more than double the Sun-Earth distance, poses considerable challenges due to the fading of laser signals as the spacecraft moves farther from Earth and the time lag exceeding 20 minutes at the mission's farthest point. As the relative positions of Earth and the spacecraft change during transmission, the DSOC systems must constantly adjust their aim to maintain a connection.
Precision and Innovation:
To achieve the necessary precision, DSOC employs advanced technology. The transceiver must be isolated from spacecraft vibrations that could disrupt laser targeting. Initial alignment is established by the Psyche spacecraft, with subsequent laser signal pointing managed autonomously by the transceiver, assisted by the Table Mountain uplink beacon laser. The Hale Telescope features a superconducting nanowire photon-counting array receiver, equipped with high-speed electronics to record the arrival time of individual photons for data decoding. Innovative signal-processing techniques have been developed to extract information from faint laser signals transmitted over vast distances.
Expanding NASA's Optical Communications Portfolio:
DSOC represents NASA's latest foray into optical communications. In 2013, the Lunar Laser Communications Demonstration achieved record-breaking data rates between Earth and the Moon. The Laser Communications Relay Demonstration, launched in 2021, established high-bandwidth optical communications relay capabilities from geostationary orbit. In the preceding year, the TeraByte InfraRed Delivery system achieved the highest-ever data rate from a satellite in low-Earth orbit to a ground-based receiver.
DSOC is pushing the boundaries of optical communications, extending its reach beyond the Moon and exploring data rates over a thousand times greater than previous optical communication tests. Success in this endeavor could set the stage for high-data rate communications, including high-definition imagery transmission, which will play a crucial role in supporting future manned missions to Mars.
For more on the mission:
DSOC is part of a series of optical communication demonstrations funded by NASA's Technology Demonstration Missions (TDM) program and the Space Communications and Navigation (SCaN) program. Managed by NASA's Jet Propulsion Laboratory in Pasadena, California, DSOC falls under the jurisdiction of TDM in NASA's Space Technology Mission Directorate and SCaN in the Space Operations Mission Directorate.
The Psyche mission is spearheaded by Arizona State University, with JPL overseeing mission management, system engineering, integration, testing, and mission operations. As the 14th mission chosen under NASA's Discovery Program, Psyche is managed by the Marshall Space Flight Center in Huntsville, Alabama. The launch service is overseen by NASA's Launch Services Program, based at the Kennedy Space Center, with Maxar Technologies providing the high-power solar electric propulsion spacecraft chassis in Palo Alto, California.
