Scientists Rescue Voyager 2 Probe on Edge of Solar System
by Jason Mick, Daily Tech, May 29, 2010 [here]
An error in Voyager 2’s memory threatened its mission on the edge of the solar system. The 33-year old probe has since been successfully fixed.
Voyager 2 was launched 33 years ago and currently remains on course, traveling out of the solar system. It is currently 8.6 billion miles (13.8 billion km) from Earth, passing through the heliosphere, a magnetic bubble that surrounds our solar system. It continues to transmit data, even as it passes through this volatile region.
However, three weeks ago the probe started transmitting garbled messages to Earth. NASA program administrators put the spacecraft in an engineering mode, restricting it to only sending health updates to Earth, while they diagnosed the issue.
It turns out the problem was caused by a single bit in the probe’s memory that had flipped. The memory was successfully reset to the proper value and normal operations resumed. In near-Earth satellites, bit flip occasionally occurs due to solar radiation. Since Voyager 2 was so far from the Sun, though, it’s unclear exactly what caused the bit flip instance.
NASA’s Voyager 2 project manager Ed Massey comments, “In some spacecraft that are closer to the sun one could think of single event upsets caused by solar activity. But we’re so far away, it’s hard to say that’s what caused it. We’re like 93, 94 AU out.”
The command to reset the probe was set on May 19, and by May 22 the probe was back in action talking to Earth in its usual fashion. … [more]