Yesterday mission managers at the Jet Propulsion Laboratory in Pasadena announced that the craft recently started sending back science data in a format no one on Earth can decode.
Voyager 2 has been switched to sending back only health and status reports while engineers at home try to figure out the glitch.
It’s no easy task, considering that Voyager 2 is about 8.6 billion miles (13.8 billion kilometers) from Earth. At that distance, it takes about 13 hours for a signal to reach the craft, and another 13 hours for it to reply.
Instant messaging this ain’t.
What the scientists do know so far is that the problem is in a part of the craft called the flight data center, the instrument that formats information for transmission to Earth.
Voyager 2 launched in 1977, and it’s been on the job exploring planets, moons, and now the very edge of the solar system for almost 33 years solid. If I had to work all the years of my life without a vacation, I’d be way more glitchy than poor Voyager.
But according to AP, the best guess is that the craft’s troubles are not age related, but cosmic-ray related.
Voyager runs on computer innards just like an average PC, and it’s out in an environment that’s unshielded from the random spray of high-energy particles—cosmic rays—whizzing through the galaxy.
“Occasionally a cosmic ray particle can cause one of the bits [in Voyager 2's memory] to flip, or it can actually have a failure in one of the bits,” Voyager project scientist Ed Stone told AP.
[Bits, by the by, are fundamental units of digital computing, in which something exists in only one of two states—on-off, north-south, 0-1, light-dark. Numbers, letters, and other forms of data are represented with lots of bits, so "flipping a bit" in Voyager's memory creates a situation akin to having a letter or number in any emails you send changed at random.]
To fix the problem, engineers would need to reset the botched bit, figure out a work-around, or crack the unexpected code.
It might seem like a lot of effort to salvage a probe that’s been around since Star Wars IV: A New Hope debuted in theaters. But if Voyager 2 and its slightly older sibling, Voyager 1, stay on course, they will boldly go where no spacecraft have gone before: outside the solar system.
Voyager 2 is in a region called the heliosheath, the “thick skin” of the bubble around our solar system created by the sun. Voyager 1 is roughly 10.5 billion miles (16.9 billion kilometers) from Earth, putting it slightly deeper into the skin.
This bubble is technically the sun’s outer atmosphere, since our star is constantly releasing charged particles in all directions, aka the solar wind. The atmosphere makes a slightly elongated cocoon around us as the sun jets at about 486,000 miles (782,000 kilometers) an hour in its orbit around the center of the Milky Way.
The solar wind slows down and gets weaker farther out from the sun, coming to an abrupt halt at a region called the heliopause. On the other side of that border lies interstellar space.
Voyager 1 should make its grand crossing in about five years, with Voyager 2 following suit not long after. Not that we’ll be able to learn much if the data being returned is unreadable.
Voyager 1 is fine, thanks, and surely we would still get plenty of good stuff from that craft. Working in tandem, however, the probes can give us a much better idea of three dimensional shapes. See, for example, proof from the twins that our solar system is “bullet shaped.”
I really do hope NASA fixes the problem and gets Voyager 2 back to business as usual. But I have to admit, the first thought that came to my mind after reading the news was: Could this be a form of alien communication? Is this V’ger in the making?
Silly, I know. Or is it???
—Images courtesy NASA/JPL