I could tell you....but I'd have to kill you.

More than none, less than hundreds.

Doug

We have no actual mission in place - so we don't know

Doug

I HAVE ONE OF THOSE...

It's sort of retired now, but it was used for lap-timing on Scalextric racing

Doug

It's an artifact of the stretched images. The sky is not that colour. It's a compunction of the fact that the overal scene is red for the stretched JPG's to produce a cyan sky.

i.e.
False Colour
http://pancam.astro.cornell.edu/pancam_ins..._False_L257.jpg
True Colour
http://pancam.astro.cornell.edu/pancam_ins..._1_True_RAD.jpg

Doug

There are several discreet sand sized particles sat on there around the wires - they're unmissable. Not clumps of the dust ( they would be the same shade as the remaining dust on the deck ) and indeed they're hidden in wind 'shadow' of various components.

Doug

However - we know that Martian wind isn't slow and steady - there are times when it's fairly harsh (harsh enough to clear much of the dust from a rover, and significantly degrade rover tracks in a single night)

We also know that the winds are occasionally strong enough to make a rover move. Not a lot...but some of the DD movies show about a pixel of shift due to high winds rocking the rover.

Doug

I'm sure everyone would love a massive long life rover on the surface of Europa....who wouldn't. Every scientist, every engineer would LOVE to have a rover on Europa.

And we'd all like New Horizons to be a Pluto Orbiter, and DAWN to be sample return, and Messenger to be a lander......

But you have to do what is feasable given time, money, and in this case technology. I would wager that if you put MSL on the surface of Europa - it would be dead with a week due to radiation, MC might be able to comment, but I'd think Mastcam would just get quietly fried. 'Shield it' you might say....that would requrie so much shielding the thing would never get off the pad. (because every kg of shielding requires kg's of fuel for landing, and THAT required multiple kg's of payload capacity )

A comparatively simple impactor / hard lander, perhaps with a decent imager, short life etc...that's currently feasable in a sensible time frame and budget and would tell us a hell of a lot about Europa.

MSL will be ( hopefully ) the 7th succesfull landing on Mars. 4 of those were/will be static landers.

If we were talking out 4th Europan lander..I'd be going 'hell yeah - let's go for wheels' - but for our first effort....one needs to be modest in requirements.

As Alan has said w.r.t. NH.....better is the enemy of good enough.

Doug

I miss them - but I'm not going to mouth of as if we're owed them, because that's just not the case.

Doug

It's not just dust on the rovers, the MI images of the very front of the solar array show some actually fairly large grains up there as well....sand sized grains...not just tiny tiny particles of dust.

http://marsrovers.jpl.nasa.gov/gallery/all...IIP2979M2M1.JPG

I think some of you are far to quick dismiss the martian wind as having near zero ability to move dust or sand. Given that we're seing such large particles up on the array deck, quite rapid erosion of rover tracks, dust tails formed by clod deposition....I'd argue that these dunes are an active formation. Not fast...but active. You can rule out water formation for them, they are far too large: consider the cross bedding - that was indicitive of the sort of ripple size one would get from moving water, not these metre scale dunes. Compared cross bedding at the lower unit at Burns Cliff ( very large, wind induced ) and Eagle crater ( very small, water induced ).

Consider Erebus crater - almost entirely filled in by sand and dust...the VERY large dune formations on it's Northern Rim..... wind can, and evidently DOES move thus stuff about.

Yes - it's roughly 1.5% of terrestrial atmospheric density - but it's also 1/3rd G. I'm not sure if the maths works out - but you're talking just shy of 5% the material mobility of Earth...I think that's quite enough, and clearly I'm not alone

http://www.news.cornell.edu/Chronicle/99/2...Mars_dunes.html

http://barsoom.msss.com/mars_images/moc/11...2306/index.html

http://www.msss.com/mars_images/moc/top102_Dec98_rel/dunes/

http://www.msss.com/mars_images/moc/2004/08/05/

Doug

Yes - HiRISE does TDI - (128 lines I think)

Essentially as eash row 'dwells' on the target, it adds the photons, then passes the count onto the next row of the 128 rows....thus increasing SNR by, in theory, 128 times. Of course there is noise and some losses within the process - but that's the theory as I understand it.

MOC NA, MOC WA, HRSC and CTX are, as I understand it, single line Pushbrooms. HiRISE a Pushbroom-with-TDI, and MARCI / THEMIS a Pushframe design. Discreet framing cameras were on board the Vikings, Mariners, and the crap SRC channel on HRSC

Doug

These 'arrival' pools have had a definition for some time, but there seems to be some confusion.

Arrival, for MER purposes, is defined as the first sol which the rover is at the Site and Drive number from which the 'big pan' is taken. If that is a Navcam mosaic only, then so be it - but preferentially, it will be a Pancam mosaic site/drive number.

i.e. for Bonneville

http://marsrovers.jpl.nasa.gov/gallery/all...0P1210L0M1.HTML - The first sol with Site 17 Drive 00 - the point at which the large Pancam mosaic was taken from....so Bonne arrival was Sol 66.
(the Pancam sequence also began on 66 after a drive - http://marsrovers.jpl.nasa.gov/gallery/all...0P1943L0M1.HTML )


i.e. for Endurance
Sol 96
http://marsrovers.jpl.nasa.gov/gallery/all...2P1214L0M1.HTML - First image from Site 20 / 02

From where the mosaic was taken
http://marsrovers.jpl.nasa.gov/gallery/all...2P2291R6M1.HTML


Site number alone isnt enough - because they often cover a LOT of ground on one Site number - so the drive number - the point at which they actually STOP to take the big pan ( and that may even mean a shuffle drive, as was the case with Endurance ) is when we count arrival. Not before. Not after.

Now yes - in both cases - Navcam mosaics were taken a sol or two before including all, some, or most of the traget - but ARRIVAL is when you stop, get the camera out, and shoot a roll of film - so as head-honcho, I'm going to make the call of the actual sol of arrival for the purpose of these two pools that are going on. My decision is final. No arguments (PS - take my S1K out of the Victoria pool, just so I can be 100% impartial about this )


Doug

Why? If you want to observe jupiter - have a jupiter orbiter. Spending the time, volume, mass, energy and data to do it from the very very very harsh surface of Europa is just stupid.

Doug

Nope. 'Arrival' has already been defined. There is no ambiguity.

The first sol that includes the site and drive number at which the big 'pan' of the target is taken.

I'm not taking part in this particular episode of pool-fettishism that's taking over (and I'm essentially pulling out of the same one in Victoria), specifically so I can wrap it up very rapidly with a discreet, specific sol number without claims of fixing it so I win.

The definiition has been written for some time already, it's not getting changed.


Doug

In a word....BALLS. Clearly you've never read anything about ESA in this forum

If you read what Steve has said - he wants to do more...but simply does not have the time. I've done my bit to help out with the Pancam updates ( Jim was in the same situation, he doesn't have the time to sit down and write something, and the podcastey type solution was one of my ideas )

I think we get plenty - we get more than we can consider to be 'expected' - it would be ace if Steve could do a bit more, but it's firmly in the 'bonus' catagory.

Doug

We get the weekly JPL updates, and 500+ images a week, and a database of MER images, and regularly posted mosaics and animations and route maps.

I think any 'duty' is being MORE than fullfilled by all concerned.

Truth be told BillyMER, I think your attitude toward those who have been putting in obscene hours for 29 straight months, is bang out of order.

You want to know how bad it could actually be....look at MEX. MER is a burst floodgate of regular and insightful information in comparison.

Doug

The expectation is that they'll just breeze past. There was an exhibition meeting of the BAA in Cambridge last weekend, and the director of the Jupiter Section showed images that demonstrate that new spot is getting darker and darker red over time, coinciding with it speeding up - and also, the GRS is getting smaller and lighter ( over the past century or so ) suggesting an opposite trend.

Doug

Exactly - there are large dunes inside Endurance and Victoria - whatever made THOSE, can make the dunes we see elsewhere.

Doug

Normally about 2 weeks isnt it?

Doug

It's an unusual thing really - all these hundreds ( thousands in the case of Soyuz ) of discarded stages...they'd make interesting projects for a philathopist with a penchent for oceanic study and space memorabillia :0

Doug

Well - 12m/s as measured by Pathfinder, I've seen 25.2m/s with V1 data, 20.1 with V2 data - (27, 56, 45 MPH respectively )

Give how much movement we saw around the areas where the wheels dumped bright material after leaving Purgatory, and how degraded 180ish-sol-old tracks were on the way out of Endurance....I find it hard to imagine that over any lengthy period, say a century, one wouldn't be able measure movement in some of this.

Doug

Yes - they baked the hell out of the optics to clear the contamination away - I found the Wild 2 images to be just about OK

Doug

Oh - I wasn't saying they were that old - but it was suggested that the air is not thick enough to make such things....but over a very long time period, it's MORE than strong engouh.

Doug

They make it to the Indian ocean a lot of the time don't they?

Part of me wonders what the seabed looks like at the places where all the Delta II GEM's, or Shuttle ET's or Soyuz boosters (dry land that one) all end up.

Doug

You see - this is why we need you around here

I must admit - the MARCI Orbit 7/8 imagery did make me go "ooo - that's all a bit complicated...but if it works..what the hell"

Doug

A similar design was used for MARCI as well, sort of half-push-broom-half-discreet-ccd, and looking through that paper, it looks like at utter barsteward to process - why would one choose that over a normal pushbroom?

Doug