When it comes to getting away from it all, the space probes Voyager 1 and Voyager 2 are the Twin Titans of distance. Both have been traveling away from Earth for over 44 years and both have crossed the heliopause and entered interstellar space, where Voyager 1 is almost 14.5 billion miles (156.2 AU) from Earth while Voyager 2 is over 12.06 billion miles or 129.81 AU away. Perhaps the most amazing fact about the twins is that they are still in communications with Earth. Well, one is and one kind of is.
“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.”
It’s serious enough that NASA issued a statement discussing the problem with Voyager 1. The attitude articulation and control system manages Voyager 1’s orientation towards Earth so its high-gain antenna always points back at Earth – well, almost at Earth. Since a message now takes over 20 hours to travel between the two points, the AACS acts like a hunter and aims slightly ahead of Earth’s current position – an extraordinary feat for software developed in 1977 and performed by 44-year-old hardware in the frigid far outer space using a minute amount of solar generated power collected by panels 14.4+ billion miles away. Are you amazed? Does this senior citizen of space probes deserve a pass for being a little ‘confused’?
“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.”
NASA believes so. The statement from the Jet Propulsion Laboratory (JPL) points out that Voyager 1 is still working well enough – its onboard fault protection systems have not self-activated and put the probe into “Safe mode” (just like on your PC) where it stays powered up but does nothing risky until the maintenance crew at Mission Control can figure out what went wrong and hopefully figure out how to fix it. Remember, there are few if any engineers left with Voyager 1 was designed nearly five decades ago. The good news is, Voyager 1’s signal hasn’t weakened, which means that the high-gain antenna is in the right position to communicate with Earth. The bad news is, the message it’s sending is still confusing and NASA hasn’t figure out why.
“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.”
Suzanne Dodd is a project manager for Voyager 1 and 2 at the Jet Propulsion Laboratory and she clearly illustrates NASA’s challenge while highlighting the huge benefit to keeping both Voyagers in operation – they’ve boldly gone where no Earth spacecraft has gone before and lived to tell us about it. If we humans are serious about space travel, we’ll need to do the same thing.
Could Voyager 1’s problems be caused by an alien probe probing it? Anything is possible, which is why both Voyagers have a 70s technology gold-plated audio-visual disc with photos of the Earth and its lifeforms, scientific information, spoken greetings, various sounds and a collection of music including works by Wolfgang Amadeus Mozart, Blind Willie Johnson and Chuck Berry. Could an alien be trying to figure out how to play it?
It's too bad Chuck Berry didn’t record a version of his signature song with the words “Go Voyager Go! Voyage be good.”