United States National Aeronautics and Space Administration (NASA) demonstration of deep space optical communications technology has completed several key milestones, finally sending the signal to Mars farthest from Earth. The optical communication technology aboard the Psyche spacecraft has proven to be effective over distances of up to 290 million miles, paving the way for future high-speed data transmission in space.
In this artist's vision United States, NASA's Psyche spacecraft is receiving laser signals from a deep space optical communications uplink ground station at JPL's Taishan facility. The DSOC experiment consisted of an uplink and downlink station, as well as a laser transceiver flying with Psyche. Source: NASA/JPL-Caltech
This summer, United States National Aeronautics and Space Administration (NASA) set a new record for laser communications at a demonstration of deep space optical communication technology, emitting laser signals from Earth to the Psyche spacecraft about 290 million miles (460 million kilometers) away. This is the same distance as when our Earth and Mars were at their farthest apart.
Shortly after reaching this milestone on July 29, the technology demonstration successfully completed its initial phase of operation, which began with the launch of the "Shishen" on October 13, 2023.
"This milestone is significant. Laser communications require very high precision, and we don't know how much performance will drop at the farthest distances until we launch the Psyche," said Meera Srinivasan, head of program operations at NASA's Jet Propulsion Laboratory in Southern California. "Now, the technology we use to track and point has been validated, confirming that optical communications can be a powerful and transformative way to explore the solar system."
In April 2021, a flying laser transceiver for the Deep Space Optical Communications (DSOC) technology demonstration was demonstrated at NASA'United States s Jet Propulsion Laboratory in Southern California and subsequently installed inside its cassette enclosure, which was later integrated United States with NASA's Psyche spacecraft. The transceiver consists of a near-infrared laser emitter that sends high-rate data to Earth and a sensitive photon-counting camera that receives low-rate data sent from the ground. The transceiver is mounted on an assembly consisting of pillars and actuators – as shown in the diagram – which is used to stabilize the optics so that they are not affected by spacecraft vibrations. Image credit: NASA/JPL-Caltech
The Deep Space Optical Communication Experiment is managed by JPL and includes a flying laser transceiver and two ground stations. Caltech's historic 200-inch (5-meter) Aperture Hale Telescope, located at the Palomar Observatory in San Diego, California, is a downlink station for laser transceivers to send data from deep space. The Optical Telescope Laboratory at JPL's Table Mountain facility near Wrightwood, California, acts as an uplink station and is capable of emitting 7 kilowatts of laser power to send data to the transceiver.
Lasers transmit data at 100 times faster than radio frequencies, so they can transmit complex scientific information as well as high-definition images and videos that astronauts need to travel to Mars and beyond to make the next big human leap.
As for the spacecraft, Psyche is still healthy, using ion propulsion to accelerate to a metal-rich asteroid in the main asteroid belt between Mars and Jupiter.
United States National Aeronautics and Space Administration's Psyche mission aims to unravel the mystery of the metal asteroid 16 Psyche, located in the asteroid belt between Mars and Jupiter. This unique mission focuses on exploring the exposed core of what is thought to be the original planet, providing a rare glimpse into the constituent elements of planetary formation. These discoveries could reveal the inner core of the Earth itself and provide clues about the history of the solar system. Source: NASA/JPL-Caltech/ASU
The data demonstrated by this technology is sent and received from Psyche in the form of bits encoded by near-infrared light, which has a higher frequency than radio waves. This higher frequency allows more data to be packaged and transmitted, which greatly increases the data transfer rate.
Even when "Psyche" is about 33 million miles (53 million kilometers) from Earth (equivalent to the closest distance Mars has to Earth), the technology demonstration can transmit data at the system's top rate of 267 megabits per second. This bitrate is similar to the download speed of broadband internet. As a spacecraft travels farther and farther, the rate at which it sends and receives data decreases.
On June 24, when Psyche was about 240 million miles (390 million kilometers) from Earth (more than 2.5 times the distance between Earth and the Sun), the project achieved a sustained downlink data rate of 6.25 megabits per second, with a maximum transmission rate of 8.3 megabits per second. While this rate is significantly lower than the maximum rate of the experiment, it is much higher than what can be achieved over this distance by an RF communication system using the same power.
The goal of deep space optical communications is to demonstrate technology that can reliably transmit data at higher speeds than other space communication technologies, such as radio frequency systems. To achieve this, the project had the opportunity to test unique datasets such as artwork and high-definition video, as well as engineering data from the Psyche spacecraft. For example, one downlink included a digital version of Arizona State University's "Psyche-inspired" artwork, images of the team's pets, and a 45-second ultra-high-definition video that parodies the last century's television test model and depicts scenes from Earth and space.
This technology demonstration delivers the first ultra-high-definition video from space from 19 million miles away to Earth on December 11, 2023, and features a cat named Taters. (Artwork, images, and videos were uploaded to Psyche and stored in its memory before launch).
"A key goal of the system is to demonstrate that the reduction in data transfer rate is directly proportional to the inverse square of distance," said Abi Biswas, Technical Specialist for JPL's Technology Demonstration Project. "We achieved this and transmitted a large amount of test data to the Psyche spacecraft via laser. In the first phase of the demonstration, nearly 11 terabits of data have been transmitted downstream. "
The power to the flight transceiver has been turned off and will restart on November 4. This activity will prove that the flight hardware can operate for at least one year.
Ken Andrews, head of flight operations for the JPL project, said: "We will turn on the power of the flying laser transceiver to do a short-term check of its capabilities. Once this is achieved, we can expect the post-connectivity phase to begin later this year to run the transceiver at full design capacity. "
The demonstration is the latest in a series of optical communications experiments funded by the Space Technology Mission Agency's Technology Demonstration Mission Program, which is managed by NASA's Marshall Space Flight Center United States in Huntsville, Alabama, and the Agency's Space Operations Mission Agency's SCaN (Space Communications and Navigation) program. The development of the flying laser transceiver was supported by partners such as MIT Lincoln Laboratory, L3 Harris, CACI, First Mode, and Controlled Dynamics Inc. Fibertek, Coherent, Caltech Optical Observatory, and Dotfast. In addition, part of the technology was developed through NASA's Small Business Innovation Research Program United States.
编译自/SciTechDaily