The next problems: Error protection on Voyager 1 caused contact to break off

NASA has temporarily lost contact with Voyager 1 and has only been able to re-establish contact via a frequency that has been unused for more than 40 years. The US space agency has made this public and explained that it is still looking for the cause of the problems on the most distant space probe from Earth. The problems occurred after the probe was sent a command to activate a heater on October 16. As a result, Voyager 1 did not report back on the usual frequency, but another signal was detected. Later, however, this also disappeared. It was later determined that Voyager 1 had changed frequency again for an unknown reason.

Fragile signal found

As NASA explains, Voyager 1 normally transmits on a frequency in the so-called X-band. Two days after the command to activate the heating, the confirmation from the space probe should have arrived at Earth. Because this was not the case, "the team correctly assumed" that an error protection system had reduced the data rate and switched to a low-power mode at a slightly different frequency. This was correct and, apart from that, the probe seemed fine. But then the data failed to appear and was only found again on a frequency in the S-band, which is reserved for even more power-saving communication. The last time it communicated with Earth on this frequency was in 1981, and it was not even clear that the signals could still be received. However, they were detected with the giant antennas of the Deep Space Network.

It is now unclear why the error protection system was activated in the first place, writes NASA. For this reason, the primary transmitters were not reactivated. Instead, a signal was sent on October 22 to check the full functionality of the now active device. The positive response was received on October 24, so contact has been re-established since then. Work is now underway to gather information about the status of the probe in order to identify the source of the fault. This could take days or weeks, NASA announces –, partly because of the immensely long signal transit times to Voyager 1 and back.

More and more difficulties

The recent problems are the latest in a rapidly growing list. Voyager 1 and its sister probe Voyager 2 are NASA's oldest active space probes. Launched in 1977, they were able to take advantage of a rare constellation for their journey, in which the four largest planets in the solar system came particularly close to each other. Both visited Jupiter and used it to gain momentum towards Saturn, where their paths diverged: Voyager 1 catapulted out of the plane of the solar system there, Voyager 2 set course for Uranus and Neptune. Originally, only a four-year mission was planned; they have now been traveling for 47 years and are still active. The twins last reached interstellar space.

It was only a year ago that Voyager 1 experienced problems, which at times even raised fears that the mission was about to come to an end. For months, the probe only sent garbage data to Earth, but in the spring those responsible managed to rectify the error. Since mid-June, all four active instruments have been collecting data again, but one of them was deactivated at the beginning of October to save power. Weeks earlier, the activation of an engine had once again revealed the difficulties caused by wear and tear.

(mho)