By laser: NASA probe sends data at 25 Mbit/s over 226 million kilometers
NASA's Psyche probe is to explore an unusual asteroid. It can also communicate with Earth by laser and has set a record.
Artistic representation of Psyche
(Bild: NASA/JPL-Caltech/ASU)
NASA has successfully communicated with the Psyche space probe by laser over a distance of almost 230 million kilometers. This is one and a half times the distance between Earth and the Sun, making it yet another record. A data rate of 25 Mbit/s was achieved during the test on April 8, which is 25 times the hoped-for bandwidth, the US space agency writes. The communication technology is designed to send data from distant space probes to Earth 10 to 100 times faster than is possible via the radio links currently in use. The maximum possible data rate of 267 Mbit/s was achieved at the beginning of December over a distance of 31 million kilometers.
A look into the future
Until now, the tests had only sent data that had been stored on the probe in advance. On April 8, the data collected by Psyche was also included, writes NASA. The data was transmitted in parallel by laser and radio waves, which enabled a subsequent comparison. This confirmed that only correct data was sent. The fact that this was possible exceeded all expectations. For example, a special cat video had previously been sent. Overall, a lot has been learned about how far the technology can be pushed in good weather conditions, adds project manager Ryan Rogalin from NASA's Jet Propulsion Laboratory. This is because, unlike radio communication, laser communication only works when the sky is predominantly blue.
Psyche was launched on October 13 towards the metal-rich asteroid after which it was named. Of the one and a half million asteroids in the asteroid belt, only around nine are predominantly metallic - Psyche is the largest of them. It is therefore of particular interest to researchers, which is why the probe was sent to it. It is currently assumed that the celestial body is the remaining core of a former planet. The analysis therefore promises unique findings. The laser communication technology on board the probe is a demonstration to show how such devices, and eventually manned spacecraft, could send significantly more data to Earth much faster.
Communicating with a spacecraft in space is an enormous challenge, especially by laser, because both the spacecraft and our planet are in motion. In the current test of the system, the near-infrared photons took almost 13 minutes to travel from the spacecraft to Earth. Both the uplink and downlink lasers have to be adjusted accordingly. This is another reason why optical communication methods have so far only been tested in low Earth orbits and as far as the moon, but laser communication with the Psyche probe is the first test in deep space. Every successful connection to the increasingly distant probe therefore also represents a new distance record.
(mho)