Over the last few months, NASA has been using its Psyche spacecraft to test a whole new communication system. The probe’s main mission is to visit an asteroid of the same name (16 Psyche) but on its journey there it has been sending laser messages back to Earth.
NASA is testing Deep Space Optical Communications (DSOC) – employing a near-infrared laser to send messages back to Earth. In November, the first test detected the laser signal from 16 million kilometers (10 million miles) away using the Hale telescope, which was for decades the largest telescope on Earth. Among the messages, there was also a cat video.
DSOC has the advantage compared to radio waves of better bandwidth speed, so we can get more data faster. But it has some challenges too, like making sure the systems are well aligned and getting new facilities that can receive the messages. So researchers consider a combination of radio and laser could be the best of both worlds and the new tests show that you can retrofit the radio antennas to do both.
The test downlinked data from twice as far as the previous test, from 31 million kilometers (20 million miles). On January 1, they downloaded a picture of the Psyche team at a rate of 15.63 megabits per second. That’s 40 times the speed you get from radio frequency.
This is the photo of the project team that was beamed from deep space.
Image Credit: NASA/JPL-Caltech
“Our hybrid antenna has been able to successfully and reliably lock onto and track the DSOC downlink since shortly after the tech demo launched,” Amy Smith, NASA’s Deep Space Network deputy manager at the Jet Propulsion Laboratory (JPL), said in a statement. “It also received Psyche’s radio frequency signal, so we have demonstrated synchronous radio and optical frequency deep space communications for the first time.”
A small device made of seven hexagonal mirrors was retrofitted on the existing radio antenna of Deep Space Station 13, which is part of NASA’s Deep Space Network in the Goldstone complex in California. A high-exposure camera was attached to the antenna subreflector at the center of the dish delivering the data from Psyche.
“It’s a high-tolerance optical system built on a 34-meter [112-foot] flexible structure,” said Barzia Tehrani, communications ground systems deputy manager and delivery manager for the hybrid antenna at JPL. “We use a system of mirrors, precise sensors, and cameras to actively align and direct laser from deep space into a fiber reaching the detector.”
The proof of concept will be tested over and over again. The hope is to still be able to track in June when Psyche would be at 2.5 times the distance Earth is from the Sun. That is as far as Mars gets to us and if the system works, it would mean much more data-intensive transmission from the Red Planet.
A future multi-wavelength antenna might look like this.
Image Credit: NASA/JPL-Caltech
The seven-segment system is a precursor for a potential 64-mirror system that would guarantee more power and better precision. And they can be added to the existing antennas of the Deep Space Network without needing to build new bespoke facilities.
“For decades, we have been adding new radio frequencies to the DSN’s giant antennas located around the globe, so the most feasible next step is to include optical frequencies,” said Tehrani. “We can have one asset doing two things at the same time; converting our communication roads into highways and saving time, money, and resources.”
Source Link: NASA Just Received Laser And Radio Messages Together From Even Deeper Space