opportunity riding the storm out
The Mars Exploration Rover Opportunity has been weathering a nasty dust storm that's obscuring enough of the Sun's light that the rover is only able to charge its batteries to about 1/3rd of maximum. This means no major activity for Opportunity until the storm subsides and the atmosphere clears up.
The rover is down to a minimal set of activities each day in order to conserve battery power. The basic life support systems keep the rover's critical mechanical parts warmed, the rover does a morning and an evening communication cycle, and it takes daily measurements of the atmospheric dust and opacity levels using the panoramic camera. Other than that, it's mostly just sitting there, riding the storm out.
Hopefully it won't get worse, but so far so good. If it does get worse, they'll start cutting out some of the daily communication sessions in order to further preserve the minimal battery power. If things get really bad, it could mean the end for Opportunity's amazing run.
Stay tuned for regular updates during this critical time for MER-B.
update: From images and data gathered by the amazing Mars Reconnaissance Orbiter, here's a glimpse of where Opportunity sits, on the edge of Victoria Crater, awaiting an opportunity to descend.
reactions, thoughts, comments, etc.
It seems to me that there would be a way to let a robot like this completely shut down (lose all elecrical power), but then when sun starts hitting the panels again, a chain reaction is started inside the robot that starts it back up. I might be over simplifying things, but I'll compare it to a cellphone. If the phone goes completely dead, there is no hope for it until somebody physically pushes the ON button again (after charging it, of course). It seems that the smart engineers in the space program could figure out a way to automatically "push the on button" once power starts flowing to the batteries and systems again.
What do you think?
Posted by: yacoubean | July 17, 2007 10:53 AM
Yacoubean, it's all about temperature. Why do we care about temperatures? For two reasons: one, certain parts can break if they go outside of their temperature ranges and two, certain parts need heating to work. That uses up energy.
The rover has to survive large temperature swings each day and the rover electronics and science instruments are particularly susceptible to damage or failure if temperatures aren't controlled. Controlling temperature means heating and that means pulling power from the batteries. You can get a feel for the dramatic temperature variations the MERs are facing here: http://marsrovers.nasa.gov/spotlight/20070612.html
Amusing as it may sound, even the batteries need to be kept warm. Temperatures can drop as low as about -155F (-103C) during the Martian night and the batteries must be kept between about 0F and 32F to operate properly (zero when the battery is supplying power and about 32F when it's charging.)
Not all of this heat comes directly from the batteries, though. There are radio-isotope heaters, ambient heat from active electronics, and the electric heaters. A combination of those must keep critical systems warm enough to function, including -- and maybe most importantly, the power system itself.
- A
Posted by: Asa Dotzler | July 17, 2007 12:02 PM
Ok, that makes sense. If the temperatures didn't drop so far, to the point that things get damaged, my scenario would probably work. In fact, I wouldn't doubt if they did build the rovers to be able to start again after losing all power, assuming all parts are in working order.
Posted by: yacoubean | July 17, 2007 12:09 PM
Yacoubean, they do have the ability to essentially "reboot" and the rovers do have an extreme power-saving mode they can go into -- they can even be commanded to turn off specific heaters to potentially sacrifice certain functionality in order to "stay alive".
Then again, we have to remember that these machines were designed to operate for about 90 days on Mars and they're currently at 1,250 and 1,225 days. My guess is that the budget here on Earth for continuing serious exploration will run out before the rovers run out :-) They've already had a pretty amazing life.
- A
Posted by: Asa Dotzler | July 17, 2007 12:20 PM