Curiosity Resumes Research Nearly a Week After Its Second Glitch This Month
NASA's Mars rover Curiosity returned to full operations Nov. 23 after experiencing its second glitch in a month nearly a week earlier.
The space agency paused all operations Nov. 17 in order to allow engineers to investigate a voltage change.
"The vehicle is safe and stable, fully capable of operating in its present condition, but we are taking the precaution of investigating what may be a soft short," Mars Science Laboratory Project Manager Jim Erickson at NASA's Jet Propulsion Laboratory said in a statement at the time.
A "soft short" refers to a leak through something that's partially conductive of electricity, and can cause a change in voltage.
Curiosity experienced a soft short the day it landed back in August 2012, its bus-to-chassis voltage shifting from 16 volts to 11 volts.
In the most recent incident, data revealed that levels had dropped down to just 4 volts, though the rover is designed to work through this and an even broader range.
Soft shorts are problematic, however, in that they decrease the rover's ability to tolerate any future shorts and can be a warning of a bigger problem at the site where it occurred.
"We made a list of potential causes, and then determined which we could cross off the list, one by one," said rover electrical engineer Rob Zimmerman of NASA's Jet Propulsion Laboratory, Pasadena, Calif.
They determined the likely cause was an internal short in Curiosity's power source, which is designed to push through in the face of such events.
After deciding to resume rover activities, the engineers discovered the probe had returned to its pre-Nov. 17 voltage level -- a reversal that is consistent with the diagnosis of an internal short in the generator. The voltage, they said, could change again.