Not a big deal, Paolo, we know you've got stuff to do. Getting around dust contamination would make sense, I guess.

Sol 2965 : the horizon is still crystal clear (quick & raw outline herewith) : features located more than 30 km away (including the Iazu Crater rim) seem to be visible !
===> I'd really like the Rover team to take an L7 PanCam horizon look around the rim of Endeavour before it goes dusty...
Click to view attachment Enjoy !

Colour image of gypsum vein...

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From sol 2974: In action taking MIs of "Monte Cristo".
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"Monte Cristo" MI mosaic...

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"Monte Cristo" in all its glory...

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Nice one, Stu!

Phil

A micro from sol 2974, "Monte Cristo":

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Darn! Nowadays I get one shift every two weeks or so. Today I was on shift and no driving due to ODY being in safe mode! My next shift is in three weeks!

Paolo

That safe mode could last until August, they say now. Ready in time for Curiosity's landing, but not good news for Opportunity.

Phil

The latest PDS release covers Sols 2701-2790, which includs the time Oppy spent approaching, studying and then destroying "Homestake"... A couple of pics made using the PDS images, shown here in advance of Oppy spotting a bigger, fatter "Homestake" to use her instruments on...

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Very pleased with the second one - first time I've been able to see and bring out the "sparkly bits" referred to by the rover team

The report on the Odyssey site doesn't seem that dire: "NASA's Mars Odyssey orbiter put itself into a precautionary standby status early Friday, June 8, Universal Time (Thursday evening, Pacific Time), when the spacecraft detected unexpected characteristics in movement of one of its reaction wheels. The spacecraft uses three of these wheels as the primary method for adjusting and maintaining its orientation. It carries a spare reaction wheel.""The spacecraft is safe, and information we've received from it indicates the problem is limited to a single reaction wheel," said Odyssey Mission Manager Chris Potts of NASA's Jet Propulsion Laboratory, Pasadena, Calif. "The path forward is evaluating the health of the reaction wheel and our options for proceeding."

Hopefully that means a week or so unless you have more specific information Phil.

I was going by this, maybe a bit alarmist...

http://news.yahoo.com/nasa-troubleshoots-p...-232759130.html



Phil

Perhaps to journalists, publicists and the general public, the main point is that it should be operating normally when Curiosity gets there. Of course the rest of us would like to see it operating normally considerably before then

That's the feeling I'm getting around the office. Chris isn't hiding anything in his oh-so-very-PR statement! It was just a bit of funny data that the spacecraft didn't like.

She's an old bird, the one...

Needless to say the MSL folks are a little rattled.

-m

It's kind of amazing to me that with all the electronic complexity of spacecraft, one of the things that most reliably fails is....THE WHEEL. Hayabusa, FUSE, Cassini....Seriously, you'd think humans would've got the hang of The Wheel by now.

Does anyone know if the WHEELS have magnetic or ball bearings? Is it the bearings that usually fail, or some other component?

Usually magnetic, to reduce all friction that you can. There's even the concept of "stiction" across the 0-rpm boundary, when the wheel is spinning very slowly but then crosses 0-rpm and goes the other direction -- even great reaction wheels can get a little "stuck" at that point. Some missions can have attitude control systems that will explicitly avoid 0-crossings, but it often cannot be avoided, depending on your pointing profile.

Wheels are indeed tricky -- just ask Oppy!

-m

Just a pair of F/RHAZ pics came down on the last batch, but confirming that Opportunity is now located quite close to the edge.
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Original: http://qt.exploratorium.edu/mars/opportuni...P9P1312L0M1.JPG

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If you are asking about the reaction wheels on ODY, I have no idea, on MER drive/steer actuators they have bearings and magnetic detents. In Oppy's RF steering actuator it is believed that the magnetic detent came loose and prevents motion, while in Oppy's IDD Az actuator we have reasons to believe it is one of the windings that is no longer operational. In Spirit's RF and RR drive actuator it is less clear but the best explanation I have heard is that there is some kind of deposit on the commutators which prevent current to flow through the windings.

Paolo

This "edge", the contact between the Meridiani deposits and the Endeavor rim deposits, is actually one of the most interesting possible things to look at. How much Opportunity's remaining instrumentation can glean is a "good topic of discussion", but this contact could tell us a lot about an era or two of Marian history....

Speaking of remaining instrumentation, I wonder if there could be some kind of creative use of the miniTES, even though the lens is covered with dust. Could it at least detect thermal radiation from "hot spots" at night, for example? Or does it, by now, have additional problems beyond the dirty lens that render it totally inoperable?

It's not just dust. MiniTES is actually broken - it doesn't work anymore.

Steve Squyres reports on Twitter (@NEEMO_Steve) (from underwater!) that Oppy just had a big cleaning event!

Now there's some welcome news! I always thought this area to the north of CY 'looked' windy, although I'm sure this is probably just random timing. Hooray!

There's a look back at Cape York on sol 2981 that will be lovely once it's downloaded.

I also though the rim "has to be windy" but you've also got to consider the solar panel angle to the wind. I never thought this particular location would be windy so, yes, random is a possibility!
This cleaning occured right on time for Oppy to participate to the "24 heures du Mans: http://www.racing-1.com/2012/06/15/24-heur...croche-la-pole/

An exposed area is always likely to be more windy than a sheltered area.

hmm, if we want Opportunity to last as long as possible, would that knowledge point us in a different direction for survival's sake?

There is a place to which Oppy could drive to ensure survival. Unfortunately there are no clays there. Winds have been observed over the last decade eroding sand dunes on the floor of Endeavour crater between Cape Tribulation and the central peak.

http://www.agu.org/pubs/crossref/2011/2010JE003675.shtml

I think that Oppy takes super-res photos of these dunes from time to time.

If Oppy became stationary then this would be the best place for Oppy to get stuck A time lapse film of a dune being eroded by wind over several years would be interesting.

Anyone see any numbers on this yet?

Any wind that might erode a dune inside Endeavour could also clean a rover on its rim. It may be true that "An exposed area is always likely to be more windy than a sheltered area." but it's not so obvious where these places would be, and Cape York is not sheltered by anything. Spirit received a huge cleaning event while 'sheltered' between Home Plate and a nearby hill called Tsiolkovsky. And the dune fields inside Endurance and Victoria were clearly sculpted by winds despite being on crater floors. In short - cleaning events can happen pretty much anywhere so no need to panic.

Phil

Differential heating between light and dark areas can also produce winds. The area in the figure in the above paper seems to be such a transition area.

It may be fortuitous that Oppy right now is also near a boundary between light and dark regions.

What constitutes a "sheltered area" depends on the direction of the wind, which may change seasonally. Wind is not random if we understand the mechanisms involved.

The topography of CY is so subtle that I think seasonal effects are the cause here. Remember we started to get cleaning events back at Greeley Haven. But we've also had big cleaning events about one and two Martian years ago. We're due for gusts and a big increase in tau around now...

I'll miss all the talk about the winds and cleaning events and jumping from lily pad to lily pad when we go from MER to MSL....
MER = the era of sail
MSL = the era of the nuclear submarine...

Me too. But the half-life of ²³⁸Pu is only about 88 years. So in a couple of centuries the real advantage of solar power will be clear, as MSL becomes a lander and then goes silent, while Oppy continues her exploration of Miyamoto crater...

What about Steve S been in NEEMO right now?

interesting since I thought the oposite! Spirit was sitting between two ridges/hills and I thought it was a Venturi effect.

Whatever the mechanism it was still a cleaning event!

Phil

... Don't you hate it when there are no pictures???

Phil

While waiting on the pictures, I'm passing the time playing 'guess the energy production' until we get the new update...

I feel your pain, Phil! At least we can take some old pics, polish them up a bit, apply some transformations, and repost them, tricking that part of the brain that needs new images, if only for a moment...

Here's mhoward's navcam pan from 2965 cropped and 3x vertical stretched, to remind us that we're still perched at the edge of one whopper of a crater:
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"I feel your pain, Phil! At least we can..."

Hmm, yes, that just might work!

I'm trying to follow my Gusev rim panorama with a version from the sol 2220s region where Bopolu, Miyamoto and Endeavour were all visible simultaneously.


Phil

Also - Fred's pic of the crater floor reminded me to post this... first, the abstacts for the Planetary Dunes workshop:

http://www.lpi.usra.edu/meetings/dunes2012/pdf/program.pdf

And then this gem:

http://www.lpi.usra.edu/meetings/dunes2012/pdf/7038.pdf

Phil

Well, if we're really desperate, there's thumbnails.

Thanks for the links, Phil.

... and a model shot.


MERB2971_2982model on Flickr

Good news regarding Odyssey [link]

"PASADENA, Calif. -- NASA's Mars Odyssey orbiter has been taken out of a protective status called safe mode. Remaining steps toward resuming all normal spacecraft activities will probably be completed by nextweek.

Controllerswill continue characterizing the performance of the replacement wheel in coming days while assessing which other activities of the spacecraft, besides nadir pointing, can be performed reliably with reaction-wheel control of attitude.

In returning to full service, Odyssey will first resume its communication relay function for NASA's Mars Exploration Rover Opportunity, and then will resume the orbiter's own scientific observations of Mars. As a priority, activities will resume for preparing Odyssey to serve as acommunications relay for NASA Mars Science Laboratory mission. "

...and love it when they're back? A short drive farther north onto the "shoreline" of CY on 2989:
http://marsrovers.jpl.nasa.gov/gallery/all...Q2P0635R0M1.JPG

I love this view, thanks Fredk

Just to make certain that I am not turned around - are we looking toward the red dot from the "shoreline" of CY on that sol 2989 image?
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Jack

That looks about right.