NASA’s Psyche mission is on its way to study a peculiar asteroid and during its cruise, the mission team has been testing a new communication system. The new approach doesn’t use radio waves but an infrared laser and it has now shown that it works successfully from the most distant place yet. Psyche was 226 million kilometers (140 million miles) from Earth when the message was sent. That’s 1.5 times the distance between the Earth and the Sun.
Psyche was transmitting its engineering data over radio waves through NASA’s Deep Space Network. The mission team decided to also transmit the data over the Deep Space Optical Communication system for the first time. The previous transmissions were not data from the spacecraft but test data.
The April 8 test showed that even from that distance, the data could be downloaded with a maximum rate of 25 Mbps. This is already well beyond the expected goal of “at least 1 Mbps” and is 10 to 100 times faster than radio transmissions.
“We downlinked about 10 minutes of duplicated spacecraft data during a pass on April 8,” Meera Srinivasan, the project’s operations lead at NASA’s Jet Propulsion Laboratory (JPL), said in a statement. “Until then, we’d been sending test and diagnostic data in our downlinks from Psyche. This represents a significant milestone for the project by showing how optical communications can interface with a spacecraft’s radio frequency comms system.”
Relative positions of the inner planets and Psyche when the data was sent.
Image Credit: NASA/JPL-Caltech
Previous tests had the spacecraft much closer – just tens of millions of kilometers away. Images and even a cat video were sent back from deep space. The technology continues to show promise but there are still a few problems that need to be ironed out. For example, optical observations are stopped by clouds. Radio communications do not suffer from this issue.
“We’ve learned a great deal about how far we can push the system when we do have clear skies, although storms have interrupted operations at both Table Mountain and Palomar on occasion,” said Ryan Rogalin, the project’s receiver electronics lead at JPL.
The team will test the system again in June when Psyche will be at 2.5 times the distance Earth is from the Sun. This is the maximum distance between Mars and Earth, and if the approach works, then it is possible to create a data-intensive network between Earth and Mars.
