Starship Asterisk*

Dust devils

http://www.msss.com/mars_images/moc/7_3 ... index.html
http://www.msss.com/mars_images/moc/7_1_99_devils/

http://antwrp.gsfc.nasa.gov/apod/ap031230.html

http://mars.jpl.nasa.gov/MPF/index1.html

I was looking for the other link, oh well,,,next time

I've been trying to find the article on nasa.gov but I can't locate it, though I do remember them saying that after the dust devil encounter, Spirit was producing more energy through it's solar arrays that it did when it first landed!

Right you are Empeda2! I remember reading that power levels unexpectedly increased with the passage of a nearby dust devil, which 'blew off' the accumulated layer of dust on the solar panels.

A couple thoughts about that and similar incidents, if I may....

Both rovers registered increased ground plane voltages during the passage of nearby dust devils.

Tribo-electric currents at local noon on Mars can exceed 800 watts per metre squared. I wonder what the readings were during dust devil encounters?

And of course the old 'dust devils' cleaning off the solar panels - that's helped them a great deal too.

Concerning rover milage...

The rover instruments include gamma ray spectrometers. The integration times for those instruments mean that for any given reading, the instrumentation must remain in place long enough to gather a sampling of backscattered gamma rays.

I note that _days_ were often spent gathering that data and is one of the reasons the rovers traveled so slowly. Another is that during the Martian winter, the amount of useful sunlight used to replenish batteries was limited. Mission planners frequently choose locations/rover positions where sun angles were maximized and rover motions limited to make the most of what energy they could gather from the solar panels.

The original mission plans assumed the rovers would only last approx. 90 days, and the maximum travel range would be limited to a couple hundred metres. Clever use of available solar energy resource(s) and careful monitoring of power consumption has allowed the rovers to last far longer than originally planned.

Both rovers have become 'stuck' at one point or another in extremely loose dune materials. Given 0.379 Earth's gravity, almost zero atmospheric pressure AND constant bombardment by tribo-electric energy, the composition of the solids that make up the dunefields, is far different than any earthly comparison.

Extreme caution is and has been exercised when choosing rover motion paths... a wise move, is better than getting permanently stuck in one of the dunes!

I suppose a way to look at it is to imagine yourself in a warehouse or something that's totally pitch black, and you've never been there before - you've got to feel your way around.

If you think about it like that - 4 miles total travel is quite a lot!

Empeda2,
I think that they are counting total distance traveled in any direction. if the rover rolls foreward 20', then finding no clear path to travel backs up 18' then turns and rolls foreward 10' it has only traveled 12' from its original point of origin but the odometer indicated it has traveled 48'. I believe this is how they are tracking distance traveled, By total odometry.

sodadigital wrote:Hi!

The excerpt mentiones that both vehicles have traveled 4 and 3.5 miles respectively.

Is this correct or is it a typo?

I think it is a very short distance to run in two years!

I think that's as the crow flies - even if it isn't - remember these things are pretty automonous, and they have to stop and do 'science' all the time two....

Hello Aqua

What you say seems logical

The point I was trying to make.. is that EVERYWHERE the rovers have been, there are signs of current and on-going erosion. And IF those features ARE current, as they appear to be, then they were NOT caused by water.

Again, many of the MAJOR erosional features may eventually be proven to have been caused by a combination of windborn solids acting like fluids, and gases liberated from below the surface by temperature increases during planetwide dust storms.

The ancient large erosion features WERE probably caused by the release of huge volumes of water - liberated by either volcanic heat or heat generated by meteoric or cometary impact(s). Some or most of that water may have come originally from comets. OR from condensates as Mars formed...?

I believe it is correct given that it spent all thet time scoping out Eagle crater and then Endurance crater (wasn't Burns cliff interesting) and the fact that opportunity spent weeks trapped in a sand dune then traveled in 30-40' segments.. When you travel no more that approx 100' per day (average) and spend some all day sols doing science observations, you don't travel far quickly.

Spirit also spent time trying to traverse the plains of Mars prior to becoming a mountain climber and loosing the use of 1 drive wheel. All in all though, not bad for something that has been working for 8 times its designed lifetime.

Hi!

The excerpt mentiones that both vehicles have traveled 4 and 3.5 miles respectively.

Is this correct or is it a typo?

I think it is a very short distance to run in two years!

Like that lil pink bunny.. the MER rover's just keep on keeping on! HO!

Today's image demonstrates just how much the transport of dust, sand(s), rock and pebbles modify's the Martian surface.

LIQUIFACTION is the 'name of the game' on Mars! i.e. Solids act like fluids when held in suspension...

This image, once again, demonstrates mass transportaion by factors other than liquid water.