Engineers have decided why NASA’s Voyager 1 probe has been transmitting gibberish for almost 5 months, elevating hopes of recovering humanity’s most distant spacecraft.
Voyager 1, touring outbound some 15 billion miles (24 billion km) from Earth, began beaming unreadable knowledge right down to floor controllers on November 14. For almost 4 months, NASA knew Voyager 1 was nonetheless alive—it continued to broadcast a gentle sign—however couldn’t decipher something it was saying.
Confirming their speculation, engineers at NASA’s Jet Propulsion Laboratory (JPL) in California confirmed a small portion of corrupted reminiscence brought about the issue. The defective reminiscence financial institution is situated in Voyager 1’s Flight Knowledge System (FDS), one in all three computer systems on the spacecraft. The FDS operates alongside a command-and-control central pc and one other system overseeing angle management and pointing.
The FDS duties embrace packaging Voyager 1’s science and engineering knowledge for relay to Earth by way of the craft’s Telemetry Modulation Unit and radio transmitter. Based on NASA, about 3 % of the FDS reminiscence has been corrupted, stopping the pc from finishing up regular operations.
Optimism rising
Suzanne Dodd, NASA’s mission supervisor for the dual Voyager probes, advised Ars in February that this was probably the most critical issues the mission has ever confronted. That’s saying one thing as a result of Voyager 1 and a pair of are NASA’s longest-lived spacecraft. They launched 16 days aside in 1977, and after flying by Jupiter and Saturn, Voyager 1 is flying farther from Earth than any spacecraft in historical past. Voyager 2 is trailing Voyager 1 by about 2.5 billion miles, though the probes are heading out of the Photo voltaic System in numerous instructions.
Usually, engineers would attempt to diagnose a spacecraft malfunction by analyzing knowledge it despatched again to Earth. They could not try this on this case as a result of Voyager 1 has been transmitting knowledge packages manifesting a repeating sample of ones and zeros. Nonetheless, Voyager 1’s floor workforce recognized the FDS because the seemingly supply of the issue.
The Flight Knowledge Subsystem was an innovation in computing when it was developed 5 a long time in the past. It was the primary pc on a spacecraft to make use of risky reminiscence. Most of NASA’s missions function with redundancy, so every Voyager spacecraft launched with two FDS computer systems. However the backup FDS on Voyager 1 failed in 1982.
As a result of Voyagers’ age, engineers needed to reference paper paperwork, memos, and blueprints to assist perceive the spacecraft’s design particulars. After months of brainstorming and planning, groups at JPL uplinked a command in early March to immediate the spacecraft to ship again a readout of the FDS reminiscence.
The command labored, and Voyager.1 responded with a sign totally different from the code the spacecraft had been transmitting since November. After a number of weeks of meticulous examination of the brand new code, engineers pinpointed the places of the unhealthy reminiscence.
“The workforce suspects {that a} single chip answerable for storing a part of the affected portion of the FDS reminiscence isn’t working,” NASA stated in an replace posted Thursday. “Engineers can’t decide with certainty what brought about the problem. Two prospects are that the chip may have been hit by an lively particle from area or that it merely might have worn out after 46 years.”
Voyager 1’s distance from Earth complicates the troubleshooting effort. The one-way journey time for a radio sign to achieve Voyager 1 from Earth is about 22.5 hours, which means it takes roughly 45 hours for engineers on the bottom to find out how the spacecraft responded to their instructions.
NASA additionally should use its largest communications antennas to contact Voyager 1. These 230-foot-diameter (70-meter) antennas are in excessive demand by many different NASA spacecraft, so the Voyager workforce has to compete with different missions to safe time for troubleshooting. This implies it’ll take time to get Voyager 1 again to regular operations.
“Though it might take weeks or months, engineers are optimistic they’ll discover a means for the FDS to function usually with out the unusable reminiscence {hardware}, which might allow Voyager 1 to start returning science and engineering knowledge once more,” NASA stated.
