Further than the sun, NASA's Psyche spacecraft transmitted data via laser over a record-breaking distance, and did so even faster than expected.
Radio frequencies remain the most reliable medium for deep space communications, connecting Earth with Mars rovers, planet-orbiting satellites, and even into interstellar space with the Voyager probes. But transmitting huge amounts of data across the solar system can take time. For example, it took him 15 months to transmit to Earth her 50 GB of data from New Horizons' close encounter with Pluto.
Using light could significantly speed up that process, at least in some cases. Data can be encoded more densely in light waves than in radio waves, allowing larger packets to be transmitted in less time. Previous high-speed tests have used lasers to transmit data between satellites and the ground, or even from lunar orbit to Earth, but things become more difficult at longer distances.
Now, NASA has broken the distance record for data transmission by laser. On April 8, the Psyche spacecraft, currently on its way to the asteroid belt, transmitted data to Earth from more than 140 million miles (225 million kilometers) away. This is about 1.5 times the distance to the Sun and 14 times farther than the device's first test in November.
The goal was to prove that the spacecraft could transmit at up to 1 megabit per second (Mbps), but test clock speeds were up to 25 Mbps, much higher than that. The Deep Space Optical Communications (DSOC) instrument aboard Psyche transmitted a copy of the engineering data to the Palomar Observatory in California, while simultaneously transmitting the same data via radio to NASA's deep space network.
For context, Netflix recommends 25 Mbps to stream the service in 4K.
“During the April 8 pass, we downlinked approximately 10 minutes of replicated spacecraft data,” said Meera Srinivasan, the project's operations director. “Until then, we had been transmitting test and diagnostic data on the downlink from Psyche. This is an important milestone.”
Other recent experiments include sending data from a ground station to Psyche, a round trip distance of 280 million miles (450 million km) overnight, and multiple receivers in different regions. There are experiments such as receiving signals at the same time using . This can be important if the connection is interrupted due to weather conditions in a region.
The research team says this technology demonstration is an important step toward faster transmission of high-resolution images and data that will be needed when humans eventually set foot on Mars.
Source: NASA