NASA has just received both laser and radio messages from deeper space
Over the past few months, NASA has been using its Psyche spacecraft to test an entirely new communications system. The probe’s main mission is to visit an asteroid with the same name (16 Psyche), but during its journey there it was sending laser messages to Earth.
NASA is testing Deep Space Optical Communications (DSOC) – using near-infrared lasers to send messages to Earth. In November, the first test detected the laser signal from 16 million kilometers (10 million miles) away using the Hale Telescope, which for decades was the largest telescope on Earth. Among the messages, there was also a video of cats.
DSOC has the advantage over radio waves of better bandwidth speed, so we can get more data faster. But there are some challenges too, like making sure the systems are well compatible and getting new facilities that can receive the messages. So researchers consider that a combination of radio and laser could be the best of both worlds, and new tests show that you can modify radio antennas to do both.
The test linked twice as much data as the previous test, from 32 million kilometers (20 million miles). On January 1, they downloaded a Psyche team photo at a rate of 15.63 Mbps. This is 40 times the speed you get from radio frequency.
This is an image of the project team broadcast from deep space.
Image credit: NASA/JPL-Caltech
“Our hybrid antenna was able to successfully and reliably lock and track the DSOC downlink shortly after the technology demonstration launch,” Amy Smith, deputy director of NASA’s Deep Space Network at Jet Propulsion Laboratory (JPL), said in a statement. “It also received a radio frequency signal from Psyche, so we demonstrated simultaneous radio and optical communications in deep space for the first time.”
A small device made of seven hexagonal mirrors has been retrofitted onto the existing radio antenna of Deep Space Station 13, part of NASA’s Deep Space Network at the Goldstone Complex in California. A high-exposure camera was connected to the antenna subreflector in the center of the dish to communicate data from Psyche.
“It is a highly durable optical system built on a 34-meter (112-foot) flexible structure,” said Barzeya Tehrani, deputy director of ground communications systems and hybrid antenna delivery manager at JPL. “We use a system of mirrors, tiny sensors and cameras to align and direct the laser from deep space to the fibers arriving at the detector.”
The proof of concept will be tested again and again. The hope is that we will be able to track in June when Psyche’s distance will be 2.5 times the distance between Earth and the Sun. This is the furthest we can get from Mars, and if the system succeeds, it will mean a much denser data transmission from the Red Planet.
The multi-wavelength antenna of the future might look like this.
Image credit: NASA/JPL-Caltech
The seven-segment system is a precursor to a potential 64-mirror system that ensures more power and better resolution. They can be added to existing deep space network antennas without the need to build new dedicated facilities.
“For decades, we have been adding new radio frequencies to existing giant DSN antennas around the world, so the most feasible next step is to include optical frequencies,” Tehrani said. “We can have a single asset that does two things at the same time; transforms our communications routes into highways and saves time, money and resources.