NASA's Deep Space Optical Communications (DSOC) experiment, which is onboard the Psyche asteroid mission spacecraft, successfully transmitted engineering data from over 140 million miles (226 million kilometers) away, 1½ times the distance between Earth and the Sun. The near-infrared transceiver’s 22-centimeter aperture telescope is mounted on an isolation-and-pointing assembly that stabilizes the optics and isolates it from spacecraft vibrations.
The data sent back by the DSOC transceiver on Psyche was collected by the 200-inch (5.1-meter) Hale Telescope at Caltech’s Palomar Observatory in San Diego County, California, using a sensitive superconducting nanowire photon-counting receiver to demonstrate high-rate data transfer.
Signals sent back to the spacecraft are emitted by a high-power near-infrared laser transmitter at the Jet Propulsion Laboratory’s Table Mountain facility near Wrightwood, California.
During the April 8 test, the spacecraft transmitted test data at a maximum rate of 25 Mbps, which far surpasses the project’s goal of proving at least 1 Mbps was possible at that distance.
"We downlinked about 10 minutes of duplicated spacecraft data during a pass on April 8,” said Meera Srinivasan, the project’s operations lead at NASA’s Jet Propulsion Laboratory in Southern California. “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.”
NASA is also working using an array of receivers that are geographically dispersed on different mountains to boost the signal.
