Puzzling telemetry from Voyager-1 suggests problem
Engineers are puzzling over strange operational data coming from Voyager-1, launched in 1977 and now in interstellar space more than 14 billion miles away, that suggests a technical problem but also makes no sense.
The engineering team with NASA’s Voyager 1 spacecraft is trying to solve a mystery: The interstellar explorer is operating normally, receiving and executing commands from Earth, along with gathering and returning science data. But readouts from the probe’s attitude articulation and control system (AACS) don’t reflect what’s actually happening onboard.
The AACS controls the 45-year-old spacecraft’s orientation. Among other tasks, it keeps Voyager 1’s high-gain antenna pointed precisely at Earth, enabling it to send data home. All signs suggest the AACS is still working, but the telemetry data it’s returning is invalid. For instance, the data may appear to be randomly generated, or does not reflect any possible state the AACS could be in.
The issue hasn’t triggered any onboard fault protection systems, which are designed to put the spacecraft into “safe mode” – a state where only essential operations are carried out, giving engineers time to diagnose an issue. Voyager 1’s signal hasn’t weakened, either, which suggests the high-gain antenna remains in its prescribed orientation with Earth.
Figuring out what has happened is made more difficult by distance. It takes about 20 hours for signals to get from Voyager-1 to Earth, even at the speed of light. Thus, any attempted fix will arrive almost two days after it first occurred, at the soonest.
Both Voyager-1 and Voyager-2 are still operating, though at significantly reduced power. It is expected that sometime in the next few years their nuclear power sources will finally be unable to produce enough power to keep them functioning. If so, both spacecraft will have survived the maximum time predicted when launched.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
Engineers are puzzling over strange operational data coming from Voyager-1, launched in 1977 and now in interstellar space more than 14 billion miles away, that suggests a technical problem but also makes no sense.
The engineering team with NASA’s Voyager 1 spacecraft is trying to solve a mystery: The interstellar explorer is operating normally, receiving and executing commands from Earth, along with gathering and returning science data. But readouts from the probe’s attitude articulation and control system (AACS) don’t reflect what’s actually happening onboard.
The AACS controls the 45-year-old spacecraft’s orientation. Among other tasks, it keeps Voyager 1’s high-gain antenna pointed precisely at Earth, enabling it to send data home. All signs suggest the AACS is still working, but the telemetry data it’s returning is invalid. For instance, the data may appear to be randomly generated, or does not reflect any possible state the AACS could be in.
The issue hasn’t triggered any onboard fault protection systems, which are designed to put the spacecraft into “safe mode” – a state where only essential operations are carried out, giving engineers time to diagnose an issue. Voyager 1’s signal hasn’t weakened, either, which suggests the high-gain antenna remains in its prescribed orientation with Earth.
Figuring out what has happened is made more difficult by distance. It takes about 20 hours for signals to get from Voyager-1 to Earth, even at the speed of light. Thus, any attempted fix will arrive almost two days after it first occurred, at the soonest.
Both Voyager-1 and Voyager-2 are still operating, though at significantly reduced power. It is expected that sometime in the next few years their nuclear power sources will finally be unable to produce enough power to keep them functioning. If so, both spacecraft will have survived the maximum time predicted when launched.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
It is puzzling. It’s been a long time since I last refreshed myself on the layout of Voyager’s computers, but I believe that there is a dedicated computer for the collection, formatting and transmission of telemetry. It is possible that neither the Articulation computer or the Communications computer are malfunctioning, but rather the connection between them has developed a defect, preventing the Communications computer from receiving correct data from the Articulation computer. Or possibly a memory fault in either of them which results in incorrect data.
Hopefully though the answer is as simple as a few flipped bits.
It hit the Flammarion Wall :-P
My 98-year old Father is exhibiting the same kind of behavior.
Communication difficulties limit prompt remediation efforts.