Engineers have discovered why NASA’s Voyager 1 probe continued to transmit gibberish for nearly five months, raising hopes of recovering humanity’s most distant probe.
Voyager 1, traveling some 15 billion miles (24 billion km) from Earth, began transmitting indecipherable data to ground controllers on November 14. For almost four months, NASA knew Voyager 1 was still alive. Voyager 1 continued to transmit a stable signal. But I couldn’t decipher anything about what it was saying.
Confirming their hypothesis, engineers at NASA’s Jet Propulsion Laboratory (JPL) in California confirmed that a small portion of corrupted memory was the cause of the problem. The defective memory bank is located in Voyager 1’s Flight Data System (FDS), one of three computers on board the spacecraft. The FDS operates in parallel with a command and control central computer and another device that monitors attitude control and direction.
FDS’s mission includes packaging Voyager 1’s science and engineering data for relay to Earth via the spacecraft’s telemetry modulation unit and radio transmitter. According to NASA, approximately 3% of FDS memory is corrupted, rendering the computer unable to perform normal operations.
a growing sense of optimism
Suzanne Dodd, NASA’s twin Voyager spacecraft project manager, told Ars in February that this was one of the most serious problems the mission had ever faced. That’s saying something, since Voyager 1 and 2 are NASA’s longest-lived spacecraft. After launching in 1977 16 days apart and flying by Jupiter and Saturn, Voyager 1 has flown further from Earth than any spacecraft in history. Although the spacecraft are leaving the solar system in different directions, Voyager 2 lags Voyager 1 by about 2.5 billion miles.
Engineers typically try to diagnose spacecraft failures by analyzing the data the spacecraft sends back to Earth. In this case, Voyager 1 couldn’t do that because it was sending a data package that showed a repeating pattern of 1s and 0s. Still, Voyager 1’s ground team identified FDS as the likely cause of the problem.
The flight data subsystem was a revolution in computing when it was developed 50 years ago. This was the first computer to use volatile memory in a spacecraft. Most of NASA’s missions operate with redundancy, so each Voyager spacecraft launched with two of his FDS computers on board. However, Voyager 1’s backup FDS failed in his 1982.
Because Voyager was old, engineers had to refer to paper documents, notes, and blueprints to understand the details of the spacecraft’s design. After months of brainstorming and planning, JPL’s team uplinked his command in early March prompting the spacecraft to send a readout of her FDS memory.
The command worked, and Voyager.1 responded with a different code from the one the spacecraft had been transmitting since November. After several weeks of close inspection of the new code, engineers identified the location of the bad memory.
“The team suspects that the single chip responsible for storing some of the affected parts of FDS memory is not functioning.” NASA said in an update: Posted on Thursday. “Engineers cannot determine with certainty the cause of the problem. There are two possible possibilities: that a high-energy particle from space hit the chip, or that it simply wore out after 46 years.” It is possible that you did.”
Voyager 1’s distance from Earth complicates troubleshooting efforts. The one-way travel time for the radio signal to reach Voyager 1 from Earth is approximately 22.5 hours. This means it takes engineers on the ground about 45 hours to learn how the spacecraft responded to commands.
NASA also needs to use the largest communications antenna to communicate with Voyager 1. These 230-foot (70-meter) diameter antennas are in high demand from many other NASA spacecraft, so the Voyager team will have to compete with other missions to get time for troubleshooting. . This means Voyager 1 will take some time to return to normal operations.
“Although it may take weeks or months, engineers are optimistic that they can find a way to make FDS work properly without the unavailable memory hardware,” NASA said in a statement. Voyager 1 will then be able to begin sending back scientific and engineering data.”
