Space Lasers: NASA’s Psyche mission launched on October 13, 2023, with the goal of exploring the origin of planetary cores and studying the metallic asteroid known as 16 Psyche. The spacecraft is scheduled to reach the namesake asteroid in 2029. During the interim, the US space agency plans to utilize this time by testing novel laser optical communications technology.
NASA has confirmed a significant milestone for its Psyche spacecraft’s Deep Space Optical Communications (DSOC) experiment. This technology demonstration aims to test laser-based data links beyond the Earth-Moon system. After integrating with the spacecraft’s radio frequency transmitter, NASA reported that the DSOC module successfully transmitted a copy of engineering data from a distance of over 140 million miles (226 million kilometers).
The DSOC’s laser transceiver achieved a data rate of 25 megabits per second, sending digital bits to a downlink station on Earth. Meera Srinivasan from NASA’s Jet Propulsion Laboratory explained that during an orbital pass on April 8, the team downloaded approximately 10 minutes of duplicated spacecraft data.
Until three weeks ago, NASA engineers had been sending only test and diagnostic data through DSOC. Transmitting actual engineering data marks a significant milestone for the project, according to Srinivasan, demonstrating that optical communications can interface effectively with a spacecraft’s primary radio-based communication system.
While Psyche currently relies on conventional radio technology for data transmission to Earth, DSOC represents a potential leap forward in communication speed. NASA developed this technology demonstration to achieve data transmission rates 10 to 100 times faster than current state-of-the-art radio frequency systems, although these rates may decrease over longer distances.
On December 11, 2023, NASA’s DSOC achieved a maximum data rate of 267 Mbps when Psyche was 19 million miles (31 million kilometers) from Earth. The recent April 8 test achieved a maximum rate of 25 Mbps, still considered a significant success given that NASA anticipated only a 1 Mbps rate at that distance.
NASA has confirmed that the JPL Psyche team is gaining valuable insights into the capabilities of the DSOC system. However, it’s important to note that laser-based space communications require clear skies and favorable weather conditions for successful link establishment. In contrast, slower radio communications are less dependent on weather conditions. As a result, laser systems like DSOC are unlikely to completely replace radio frequency systems in the near future.