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Unmanned Spaceflight.com _ Spirit _ Digging in

Posted by: maycm Apr 25 2006, 03:36 PM

An interesting update at Newscientist.

Seems they are planning on using Spirit's RAT to dig down into the dirt, cm by cm.

I wonder how deep they can go? Maybe we'll find out if there is anything frozen/liquid just below the surface.

http://www.newscientistspace.com/article/dn9049-spirit-to-start-digging-the-martian-dirt.html

Posted by: djellison Apr 25 2006, 04:13 PM

Only difference between this and the trenching ( two intentional, several unintentional ) is the degree of accuracy in the depth being taken away. I don't imagine there will be any 'wow' moments, just good science.

Doug

Posted by: RNeuhaus Apr 25 2006, 06:49 PM

I realized that this kind of digging would cause more problems to Spirit than the benefit. I am supposing that the RAT has a grinding wheel grinding wheel to remove dust and weathered rock, exposing fresh rock underneath.


During the griding process, it can spatter the sand away and the powder would fall onto the already dirty panel array solar. This will would lead to lower solar incidence to the solar arrays. In spite of the fact, the RAT has performed many times with little consequences of dirty powder on the array solars but the case of grinding on the sandy surface, the thing would be worst, more spattering.

I am not sure about this consequences. But, someone who know better about this might jump his toughts. smile.gif

Rodolfo

Posted by: Ant103 Apr 25 2006, 07:11 PM

Dust may not cause problem. The high of solar panels is about 80 cm. The RAT -I think- didn't have the power to eject or dispend dust more than few decimeters.
I think that the danger is the probality of intrusion of material IN the RAT and all the instruments...

Posted by: djellison Apr 25 2006, 08:04 PM

They've not said they're going to physically RAT the soil ( that would be silly ) - just use it as a type of shovel - push stuff about.

Doug

Posted by: Bob Shaw Apr 25 2006, 08:07 PM

QUOTE (djellison @ Apr 25 2006, 05:13 PM) *
Only difference between this and the trenching ( two intentional, several unintentional ) is the degree of accuracy in the depth being taken away. I don't imagine there will be any 'wow' moments, just good science.

Doug


Doug:

Hopefully, we'll be able to see discrete layers being pulled away, rather than just the final effect - so that will be a *big* difference:

Bob Shaw

Posted by: Bob Shaw Apr 25 2006, 08:23 PM

Rodolfo:

Stirring the sand/dust should produce much less debris than a proper high-speed abrasion!

Bob Shaw

Posted by: RNeuhaus Apr 25 2006, 08:34 PM

I agree that it is more sensate to use the IDD as a showel to stirr the sand and the RAT will be off meanwhile.

Rodolfo

Posted by: Shaka Apr 25 2006, 11:02 PM

http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20060425a.html
Details on the 'dig'!

QUOTE
Spirit will use the brush on the rock abrasion tool to carefully sweep away soil, much the way an archaeologist uses a brush to uncover artifacts. At each level, Spirit will measure the mineral and chemical properties and assess the physical nature (such as grain size, texture, hardness) of the material, using the Athena science instruments on the robotic arm.

What rotation speed(s) does the brush use?
Apparently Spirit's wheels won't turn again for 4 months. sad.gif
Oh well, at least Oppy's going to be moving.

Posted by: sattrackpro Apr 26 2006, 01:14 AM

QUOTE (Shaka @ Apr 25 2006, 04:02 PM) *
Apparently Spirit's wheels won't turn again for 4 months. sad.gif
Well, I'd be very surprised if they actually sit right where they are for the next four months - for several reasons. First, the slope nearby (dead ahead to rear of rover) allows for a better tilt toward the sun (current is 11 degrees, potential is for 15 to 18 degrees.) Second, there are so many 'targets' to get to - for 'science' - that I believe they will slowly get around to over the next few months. I’m expecting at least half a dozen moves to nearby targets.

The problems associated with moving are great - ability to turn is limited, and potential for getting 'stuck' is high, unless great care is taken. They'll have to wiggle around the dead wheel, and hence they have to pre-plan every move much more carefully than in the past. Every turn will dig up the soil around where it is made, and obviously, the big rocks in the area could become a problem in any turning sequence.

There is also the rise to the immediate west of the current location, that also offers a potential greater northern tilt - perhaps five to eight more degrees - and additional targets of interest nearby.

So somewhere in the following months, I fully expect to see a visit to that rise -which won’t entail much additional driving – but will give us new views, and many more fascinating pictures to contemplate.

Posted by: Shaka Apr 26 2006, 01:40 AM

I would have expected the same sort of plan - to cover as much ground west and south as appropriate slopes would allow. I just don't see that ambition in the statement:

QUOTE
After the winter solstice in August, depending on energy levels, scientists may direct the rover to pivot around the disabled, right front wheel to get different targets within reach of the arm.

I hope somebody used 'imprecise' phrasing. huh.gif

Posted by: general Apr 26 2006, 06:45 AM

http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20060425a.html :

"The planned subsurface soil experiments will be a first for the Mars Exploration Rover mission. To conduct the study, Spirit will use the brush on the rock abrasion tool to carefully sweep away soil, much the way an archaeologist uses a brush to uncover artifacts. At each level, Spirit will measure the mineral and chemical properties and assess the physical nature (such as grain size, texture, hardness) of the material, using the Athena science instruments on the robotic arm. Of particular interest are vertical variations in soil characteristics that may indicate water-related deposition of sulfates and other minerals."

cool.gif smile.gif


EDIT: ooops...too late. Beaten by Shaka. LOL

Posted by: edstrick Apr 26 2006, 07:02 AM

I *PRESUME* they've been playing in the sand box at JPL.....

Posted by: dilo Apr 26 2006, 08:08 AM

Perhaps slightly OT, but in the newscientist article they talk about 8 months stay in the present position...
This is a huge stop (I was convinced that winter would last 5/6 months). Consider also that this will end well behind Sol1000 extended mission! huh.gif

Posted by: Vladimorka Apr 26 2006, 08:55 AM

Well, ignoring the dust buildup and battery recharge capacity, about 7 months from now (or 200 sols, if my math is correct) the solar exposure will be around tosol levels with lowest on august 6th
Another OT: in Starry Night Pro a martian day of 24.656944 hours works much better than the wikipedia value of 24.622962

 

Posted by: dilo Apr 26 2006, 09:03 AM

Thanks, Vladimorka... so we will have to wait fo a while! sad.gif

Posted by: edstrick Apr 26 2006, 10:46 AM

4 pics of the area directly in front of Spirit. Raw bands 2,5,7 composites... two with rover in view contrast stretched to improve dark soil detail. Some bright areas are saturated in the data.

Quite complicated wind ripples and granule/sand deposits.. also note bright red coating with much bluer stuff inside exposed by wheel gouges.



post slightly too big.. here's the 4th


 

Posted by: helvick Apr 26 2006, 02:35 PM

QUOTE (Vladimorka @ Apr 26 2006, 08:55 AM) *
Well, ignoring the dust buildup and battery recharge capacity, about 7 months from now (or 200 sols, if my math is correct) the solar exposure will be around tosol levels with lowest on august 6th
Another OT: in Starry Night Pro a martian day of 24.656944 hours works much better than the wikipedia value of 24.622962

By my calculations the lowest insolation level at Spirits latitude occurs on July 27th when you take eccentricity and obliquity into account and disregard the atmosphere. The insolation on that day is 2770 whr/m^2. Today it's 3200 whr/m^2 and will be back at that level on October 21. Obviously the Solar Panels' power generation capacity also depends on accumulated dust and atmospheric opacity though and my best guess for that at the moment is that the minimum power generation level for Spirit will be on September 8th assuming dust deposition remains constant. After that the rate at which Insolation rises increases faster than losses due to dust for a while but the amount of dust is very problematic now and without a cleaning event Spirit's ability to generate power will not rise above 276 whr per sol again when horizontal.

The Wikipedia value is the Martian Siderial day, your better value for Starry Night is closer to the Solar day (24.65979 earth hours).

Posted by: Joffan Apr 26 2006, 10:38 PM

The thing I like most, regarding all this discussion on what to do next, is the belief in a long-term working (if somewhat crippled) rover. For example, at http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20060425a.html, we have sentiments like:

QUOTE
After the winter solstice in August, depending on energy levels, scientists may direct the rover to pivot around the disabled, right front wheel to get different targets within reach of the arm. When the winter season is over and solar energy levels rise again, scientists will direct Spirit to leave its winter campaign site and continue examining the "Columbia Hills."

So this is planning what to do in maybe 9 months time. Awesome.

Posted by: Jeff7 Apr 27 2006, 01:42 AM

QUOTE
So this is planning what to do in maybe 9 months time. Awesome.


biggrin.gif I can't imagine that things will get worse for it over the winter. It's away from El Dorado, which was apparently a prime location for dust deposition, and on a bit of a slope. It might get a bit of a cleaning from light winter breezes. If nothing else, the low winds of winter might help ensure less dust buildup.



This is just going to be so utterly devastating when they finally do announce to the world that the rovers are no more.

Posted by: Shaka Apr 27 2006, 02:02 AM

Like losing family. sad.gif

wheel.gif Once more into the breach, dear friends!

Posted by: RNeuhaus Apr 27 2006, 02:31 AM

During the winter, Spirit will be almost hibernated. Only moving part will be its IDD and MST. These won't kill anything to Spirit until after between Sept-Oct.

Rodolfo

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