NASA has Mars rover Curiosity sleep through radiation blast

As NASA engineers work on fixing Curiosity's computer, a solar radiation blast raced toward Mars

The NASA Mars rover Curiosity is running again after engineers put it to sleep for a day this week to protect it from a powerful solar storm.

On Tuesday, the sun unleashed what appeared to be a major blast of radiation and solar wind, called a coronal mass ejection, that was heading straight at Mars.

NASA feared the blast could disrupt Curiosity's electrical charge. The rover has been working on Mars since last August.

A working rover hit with a heavy load of radiation could suddenly perceive a zero as a one or a one as a zero, said Richard Cook, Curiosity's project manager.

"When [a rover is] on and you zap it with radiation, which is itself a little electrical charge, you can disrupt it," Cook told Computerworld . "If it's off, these radiation hits don't really affect it."

So when Curiosity awoke from its normal night's sleep on Wednesday, NASA scientists immediately had it to go back to sleep for the rest of the day.

The rover, which is steeled against normal space radiation, awoke again on Thursday without any apparent damage from the radiation blast, according to Cook.

The radiation blast wasn't as strong as scientists had feared. Cook called it a "big event, but not a very big event." However, he did say it was good that NASA engineers were prepared for the event and acted cautiously.

NASA had to deal with the solar burst at the same time it was repairing a computer problem onboard Curiosity.

NASA engineers last week had detected a hardware problem that was causing multiple memory errors on the rover's main computer, which is called the A-Side. The NASA team put Curiosity into a safe mode and switched it over to run on its backup computer system, or its B-Side.

NASA, though, is still trying to identify the hardware problem so a software workaround can be built. Engineers are also trying to repair the A-Side software so it can serve as the new backup system.

For several days now, Curiosity has been doing minimal activity while scientists work on its systems. According to Cook, the team is hoping to get it fully working again next week. "It depends on what we learn in the next couple of days," he said.

"It could be early next week but if the problem is something that causes us to have to go back and erase the memory from the A-Side and restore it from the ground, that could take a little more time. Then we're looking at maybe the end of next week," Cook added.

Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, or subscribe to Sharon's RSS feed . Her e-mail address is

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