NASA’s Hybrid Antenna Ushers In a New Era of Deep Space Laser Communication
Deep Space Station 13 at NASA’s Goldstone complex in California – part of the agency’s Deep Space Network – is an experimental antenna that has been retrofitted with an optical terminal. In a first, this proof of concept received both radio frequency and laser signals from deep space at the same time. Credit: NASA/JPL-Caltech
NASA’s introduction of a hybrid antenna into the DSN marks a significant advancement in space communication, enabling faster data transmission and supporting the demands of future exploration.
Capable of receiving both radio frequency and optical signals, the DSN’s hybrid antenna has tracked and decoded the downlink laser from DSOC, aboard NASA’s Psyche mission.
An experimental antenna has received both radio frequency and near-infrared laser signals from NASA’s Psyche spacecraft as it travels through deep space. This shows it’s possible for the giant dish antennas of NASA’s Deep Space Network (DSN), which communicate with spacecraft via radio waves, to be retrofitted for optical, or laser, communications.
By packing more data into transmissions, optical communication will enable new space exploration capabilities while supporting the DSN as demand on the network grows.
A close-up of the optical terminal on Deep Space Station 13 shows seven hexagonal mirrors that collect signals from DSOC’s downlink laser. The mirrors reflect the light into a camera directly above, and the signal is then sent to a detector via a system of optical fiber. Credit: NASA/JPL-Caltech
Enhancements in Deep Space Communication
The 34-meter (112-foot) radio-frequency-optical-hybrid antenna, called Deep Space Station 13, has tracked the downlink laser from NASA’s Deep Space Optical Communications (DSOC) technology demonstration since November 2023. The tech demo’s flight laser transceiver (see image below) is riding with the agency’s Psyche spacecraft, which launched on October 13, 2023.
The hybrid antenna is located at the DSN’s Goldstone Deep Space Communications Complex, near Barstow, California, and isn’t part of the DSOC experiment. The DSN, DSOC, and Psyche are managed by NASA’s Jet Propulsion Laboratory in Southern California.
The Deep Space Optical Communications (DSOC) technology demonstration’s flight laser transceiver is shown at NASA’s Jet Propulsion Laboratory in Southern California in April 2021, before being installed inside its box-like enclosure that was later integrated with NASA’s Psyche spacecraft. The transceiver consists of a near-infrared laser transmitter to send high-rate data to Earth, and a sensitive photon-counting camera to receive ground-transmitted low-rate data. The transceiver is mounted on an assembly of struts and actuators – shown in this photograph – that stabilizes the optics from spacecraft vibrations. 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,” said Amy Smith, DSN deputy manager at JPL. “It also received Psyche’s radio frequency signal, so we have demonstrated synchronous radio and optical frequency deep space communications for the first time.”
In late 2023, the hybrid antenna downlinked data from 20 million miles (32 million kilometers) away at a rate of 15.63 megabits per second – about 40 times faster than radio frequency communications at that distance. On Jan. 1, 2024, the antenna downlinked a team photograph that had been uploaded to DSOC before Psyche’s launch.
Now that Goldstone’s experimental hybrid antenna has proved that both radio and laser signals can be received synchronously by the same antenna, purpose-built hybrid antennas (like the one depicted here in an artist’s concept) could one day become a reality. Credit: NASA/JPL-Caltech
In order to detect the laser’s photons (quantum particles of light), seven ultra-precise segmented mirrors were attached to the inside of the hybrid antenna’s curved surface. Resembling the hexagonal mirrors of NASA’s James Webb Space Telescope, these segments mimic the light-collecting aperture of a 3.3-foot (1-meter) aperture telescope. As the laser photons arrive at the antenna, each mirror reflects the photons and precisely redirects them into a high-exposure camera attached to the antenna’s sub-reflector suspended above the center of the dish.
The laser signal collected by the camera is then transmitted through an optical fiber that feeds into a cryogenically cooled semiconducting nanowire single photon detector. Designed and built by JPL’s Microdevices Laboratory, the detector is identical to the one (see image below) used at Caltech’s Palomar Observatory, in San Diego County, California, which acts as DSOC’s downlink ground station.
Shown here is an identical copy of the Deep Space Optical Communications, or DSOC, superconducting nanowire single-photon detector that is coupled to the 200-inch (5.1-meter) Hale Telescope located at Caltech’s Palomar Observatory in San Diego County, California. Built by the Microdevices Laboratory at NASA’s Jet Propulsion Laboratory in Southern California, the detector is designed to receive near-infrared laser signals from the DSOC flight transceiver traveling with NASA’s Psyche mission in deep space as a part of the technology demonstration. Credit: NASA/JPL-Caltech
“It’s a high-tolerance optical system built on a 34-meter 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.”
Tehrani hopes the antenna will be sensitive enough to detect the laser signal sent from Mars at its farthest point from Earth (2 ½ times the distance from the Sun to Earth). Psyche will be at that distance in June on its way to the main asteroid belt between Mars and Jupiter to investigate the metal-rich asteroid Psyche.
The seven-segment reflector on the antenna is a proof of concept for a scaled-up and more powerful version with 64 segments – the equivalent of a 26-foot (8-meter) aperture telescope – that could be used in the future.
During a test of the experimental antenna, this photo of the project team at JPL was downlinked by the DSOC transceiver aboard Psyche. Credit: NASA/JPL-Caltech
Future Prospects and Infrastructure Development
DSOC is paving the way for higher-data-rate communications capable of transmitting complex scientific information, video, and high-definition imagery in support of humanity’s next giant leap: sending humans to Mars. The tech demo recently streamed the first ultra-high-definition video from deep space at record-setting bitrates.
Retrofitting radio frequency antennas with optical terminals and constructing purpose-built hybrid antennas could be a solution to the current lack of a dedicated optical ground infrastructure. The DSN has 14 dishes distributed across facilities in California, Madrid, and Canberra, Australia. Hybrid antennas could rely on optical communications to receive high volumes of data and use radio frequencies for less bandwidth-intensive data, such as telemetry (health and positional information).
“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.”
Mission and Technological Advancements
DSOC is the latest in a series of optical communication demonstrations funded by NASA’s Technology Demonstration Missions (TDM) program and the agency’s Space Communications and Navigation (SCaN) program. JPL, a division of Caltech in Pasadena, California, manages DSOC for TDM within NASA’s Space Technology Mission Directorate and SCaN within the agency’s Space Operations Mission Directorate.