NASA launched the twin Voyager probes in 1977 on a mission to study the outer solar system and beyond. Now, almost 50 years later, both spacecraft are still going strong. Well, Voyager 2 was doing fine the last time we heard from it, but a small mistake means the iconic spacecraft can't communicate with Earth right now.
Voyager 2 is 12.4 billion miles (19.9 billion kilometers) from Earth, past the heliopause that represents the edge of the sun's influence. At that distance, Voyager needs to point its communication antenna precisely to maintain contact with NASA's Deep Space Network. NASA reports that a series of planned commands on July 21 had the unintended effect of orienting the antenna 2 degrees away from Earth. In this position, Voyager 2 is unable to receive commands or transmit data back to NASA.
As far as anyone on the ground knows, Voyager 2 is still fully operational and beaming data off into space as if it's transmitting to Earth—the spacecraft doesn't know that it's pointed in the wrong direction. Luckily, there's a fallback for just such an event. Voyager 2 is programmed to perform an automatic reset every few months, and the next one is scheduled for October 15. NASA expects that Voyager 2 will come back online at that time, with its communication array once again pointed in the right direction.
Miraculously, both Voyager probes are still online after nearly five decades. This is not the first disruption for the Voyager probes. Voyager 2 encountered an error several years back that temporarily shut down all of its science instruments, and both spacecraft are running low on power. NASA equipped them with a radioisotope thermoelectric generator (RTG) as it's too far away from the sun for solar panels. As the plutonium fuel decays, the generator makes a little less power year by year. NASA has slowly turned off systems and instruments to keep the probes alive for a bit longer.
This isn't even the first time Voyager 2 will be on its own for an extended period. NASA upgraded part of its Deep Space Network in late 2020, which left it unable to talk to Voyager 2 for the duration of the project. However, the spacecraft was still there eight months later when Dish 43 came back online. NASA also expects to hear from Voyager 2 after the current blip. Voyager 1 was not sent any bad commands, and it's even more distant at 15 billion miles (24 billion kilometers) from Earth.
