L’April 8, 2024 the space mission Psyche of NASA successfully sent data carried by a infrared laser beam who traveled for the beauty of 226 million km in interplanetary space (1.5 times the distance between the Earth and the Sun) before being detected on the ground. This involves sending optical information from the greater distance never accomplished in history. Psyche had already sent data to Earth via laser: in December, for example, the probe sent a video of a cat from 11 million km away. However, this is the first time the probe has sent through this technology real engineering data and not test data.
Psyche is a mission launched on October 13, 2023 with the aim of reaching the asteroid of the same name in 2026. On board is an innovative communication technology called Deep Space Optical Communications (DSOC) for sending data via a transceiver laserwhich complements traditional communication systems via radio waves.
The reason is simple: this way the transmission speed of information is much higher (up to 100 times) than radio communications. The April 8 broadcast, for example, traveled to 25Mbps (megabits per second), which is an impressive result considering the transmission distance: it is a rate tens of times higher than the typical rate for radio waves and in any case well above the minimum target of 1Mbps established by NASA for DSOC. (In December, thanks to the shorter distance, the speed reached 267Mbps.)
This technology serves as technology demonstrator for a next-generation communications system useful for long-distance human missions, in particular for future human bases on Mars. Since the maximum distance between Earth and the red planet is approx 375 million km (2.5 times the Earth-Sun distance), NASA has prepared a new sending of data via DSOC to June this year, when this will be precisely the distance between Psyche and our planet. If everything works properly, the technology demonstration will be considered a success and can be implemented to create a system of rapid communication of large amounts of data between Earth and Mars.
The system though It’s still not problem-free. For example, currently a limitation of DSOC is that clouds block laser propagation, which is not the case with radio transmissions. Fortunately, it’s not an unsolvable problem, especially if you can count on it many possible reception points scattered around the globe.
