Something's Up With Voyager 1

Voyager 1 remains (and will remain for the foreseeable future) the single man-made object that is farthest from Earth at nearly 14-1/2 billion miles away.  To put a little perspective on that, the nearest stars are 4.2 to 4.3 light years away - it takes radio signals that long to go one way.  Voyager 1 is 20.5 light hours away a tiny fraction of one light year; .00239 light year to be precise.  Assuming it's even going in the right direction, it'll take Voyager 1 almost 77,000 years to get to the Alpha/Proxima star system.  The probes are expected to last another three years until 2025, but there's hope they'll make it to the Golden (50th) Anniversary of their launch in 2027. 

A couple of weeks ago, I started noticing videos in my YouTube feed that mentioned something wrong with Voyager 1.  I didn't pay much attention because there are so many deceptively labeled videos that are just screaming to get clicks that I was reluctant to believe anything was really going on.  For example, at least once a week I get videos claiming that the James Webb Space Telescope has discovered some incredible new thing, even months ago when the telescope wasn't even remotely close to being operational.  Plus, let's be honest: Voyager 1 is just about at its 45th year of a four year mission, so something like parts dying due their old age is almost overdue.  It's old hardware that has been exposed to all kinds of radiation from deep space (not to mention from Jupiter, Saturn and the sun) and the power supply is slowly running out.  

Back around the middle of the month, I went to the JPL Voyager page and didn't see anything that suggested anything was terribly wrong, but eventually my curiosity got the better of me and I watched this video.  

The video talks about strange errors in the probe’s attitude articulation and control system (AACS) and say they don’t reflect what’s actually happening. They base that on the probe being properly pointed at Earth and maintaining radio contact, which is a reasonable conclusion.  The AACS maintains the probe's position and it if it were out of position the radio link wouldn't be received on Earth.  Voyager wouldn't be heard sending funny data, it wouldn't be heard at all.

Today I went back to the JPL Voyager site and found they put up a post about this nine days ago.  As the article puts is:

“A mystery like this is sort of par for the course at this stage of the Voyager mission,” said Suzanne Dodd, project manager for Voyager 1 and 2 at NASA’s Jet Propulsion Laboratory in Southern California. “The spacecraft are both almost 45 years old, which is far beyond what the mission planners anticipated. We’re also in interstellar space – a high-radiation environment that no spacecraft have flown in before. So there are some big challenges for the engineering team. But I think if there’s a way to solve this issue with the AACS, our team will find it.”

It’s possible the team may not find the source of the anomaly and will instead adapt to it, Dodd said. If they do find the source, they may be able to solve the issue through software changes or potentially by using one of the spacecraft’s redundant hardware systems.

The post includes a fact that I've never seen before.  Every year, the Radioisotope Thermal Generators that power the Voyagers produce 4 Watts less power.  To enlarge on what I mentioned above, planning numbers are that the pair should last until at least 2025, and possibly until the 50th anniversary of their launches, in August and September of 2027.  The engineering team has shut down some subsystems to save power for others.  No science instruments have been turned off, yet.  

As I said a decade ago, if we're lucky, some day, perhaps hundreds of years from now a ship from Earth may find Voyager 1 and bring her back to whatever serves as the equivalent of the Smithsonian in those days. 

In all probability, she will simply follow the Newtonian laws of motion, cool to a couple of degrees Kelvin and glide away forever, all alone in the night.