[X] My Assistant

[dilo]

On one shot a little while back, when I posted a stereogram, the right eye picture showed the beacon and another spot of white a little further along. I wonder if we have seen the second beacon sometimes?

Joffan, could you find the image? It would be very interesting to analyze it!
About beacon images comparison, I reccomend to use my previous post sequence because pictures were assembled with the similar degree of contrast enhancement and noise reduction (apples to apples)...

PS: I already estimated the visible part of beacon should be 1m tall if located on the far rim, less if elsewere.

[prometheus]

[quote name='Shaka' date='May 16 2006, 05:01 PM' post='54294Victoria Crater is sunk into an invisible... an invisible...abyss?[/quote]

Invisible abyss? Where did you get that from? I take you didn't look at this:
http://gallery.perfext.com/albums/userpics/10001/vc5.jpg
or read this:
http://gallery.perfext.com/displayimage.php?album=2&pos=70

Both the pamcam and the 3d generated image show the land dropping away to the left where the dark streaks are located. So why assume the land behind Victoria is flat and doesn't rise up? Do you have access to detailed elevation contour line data? Also the lower elevation to the left may help to explain the dark streaks as this lower height side of the crater may have formed a wind tunnel effect for exiting winds.

[djellison]

Yeah, how long are you going to let us wallow in the dust? And how is that request for a right angle drive (to the beacon sight line) coming?

I'd rather make 30m more progress to Victoria than have a 30m baseline for fairly useless imagery at this distance

Doug

[Tesheiner]

The problem I see is that any deviation of Opportunity from the ideal line of sight through such a gap should block out the view of the far rim and extinguish the beacon. If the gap is wide enough to prevent this, the beacon should widen or narrow depending on how well Opportunity is lined up with the gap. But ever since the beacon was spotted, it has maintained its presence and size despite opportunity's deviations from a straight-line path to it.

Another problem I see with the "gap theory" is that it requires an exact vertical alignment between the near and the far rim. If the far rim is lower then the near rim (in the current line of sight) nothing would be seen through the gap, if it is higher, we would see not only the beacon through the gap but many other features over and around it.

Any chance of getting the rover drivers to take a hard left or right and drive as far as it takes to get an unambiguous answer by parallax?

No chance, I would say.
But following the "proposed path" on the route map to a point 300m S of the current position, I estimate the angular difference between the beacon's expected positions at either the near or far rims to be more then 3.5º (see headings in red on the following image). That would be more then enough to rule out one of the options.

[climber]

But following the "proposed path" on the route map to a point 300m S of the current position, I estimate the angular difference between the beacon's expected positions at either the near or far rims to be more then 3.5º (see headings in red on the following image). That would be more then enough to rule out one of the options.

At current speed that means another 18 sols including a 10 days of restricted sols which means an answer by june 10 th? Even if it will be Spirit launch Birthday (as well as my son's) we just CAN'T wait that long.

[edstrick]

"....and now the poor litte thing has shrivelled away to nothing - pancam, 14-May, no stretch...."

Obviously, the Beacon is the Periscope the Grays have been watching us with from their base in Victoria crater and they've retracted it when they realized we'd spotted it......"

Yes, Nurse.. I did take my meds today... No...!... Not the Straigjacket!... arrrrgg.

[climber]

I guess this will look weird! Anyway. We know where the heat shield has landed as well as the parachuttes. Is there any chance that the "bus" that brought Oppy to Mars make it through the atmosphere and landed on VC rim (I mean FAR rim ) (a nearly-hole in one) and show now as the beacon?
Frankly, as Oppy was slowed down by the heatshield, I think that the bus went further on the trajectory, but I'll be interested both in your comments about survivability of the bus as well as its trajectory. Just wondering if this has been addressed in the forum. Thanks.

[djellison]

I've been trying to figure out where the bus would have ended up - and I think actually - (after one considers that it's such a complex structure with such a variety of materials that it is essentially impossible to calculate this) it would have mostly burnt up, with some remaining debris falling short of the landers.

Consider the size of the cruise stage compared to its weight. The MER entry capsule was actuall quite 'dense' so it would want to push it's way through the air for longer (i.e. more kinetic energy per unit of drag )

BUT - there are parts of the cruise stage ( fuel tank, thruster clusters ) that would have survived much of entry I'm pretty sure...but until they 'fell off' the cruise stage ( which when they're bolted on strong enough to survive launch and a 60rpm spinup is going to be quite 'late' in the entry ) they would have slowed down quite quickly with the rest of the cruise stage. Thereafter they'd probably have just dropped to the surface.

All this however - constrains the debris in the line of flight - (i.e. down the long axis of the landing ellipse - roughly East-West) - so I can't imagine the cruise stage debris being >6km (and out of the landing ellipse ) to the South

BUT - all that is pure speculation. If there WERE any cruise stage debris, its impact ( typically objects hit the martian surface at 200mph..ish) would have created the sort of ejecta we saw for the heatshield impacts both at Meridiani and Gusev - both highly visible in MOC imagery.


Doug

[Guest_Sunspot_*]

There is a very dark spot slightly north east of Vostok in the MOC image that does look a little like the heatshield imapct site.

[babakm]

This one (lower left of cProto image) looks nice and fresh and is due West of the landing location. Looks too big though, IMO.

Back to Victoria, does anyone have any idea how common it is to have craters this large/deep without much of a raised rim? Could the "porous" nature of the evaporite be responsible for this?

[antoniseb]

does anyone have any idea how common it is to have craters this large/deep without much of a raised rim? Could the "porous" nature of the evaporite be responsible for this?

I don't know yet that we are seeing a large crater without much of a raised rim. How high does the rim for the crater in Arizona look from a mile away?

[djellison]

This one (lower left of cProto image) looks nice and fresh and is due West of the landing location. Looks too big though, IMO.

And not to mention:
Image start time: 2003-11-08

More than two months before Oppy arrived

Doug

[babakm]

And not to mention:
Image start time: 2003-11-08

More than two months before Oppy arrived

Doug

Hah! But it doesn't say anything about image end time! May be it was a reeeeaaal slow and careful cProto.

[marswiggle]

A little experiment here... I made a strictly square xeyed image of Victoria from JPL jpegs R2200640, S0500863 (hope I got the codes right) and added a faint grid as an artificial 'zero level', to find out relative heights around the rim.

I'm not going to speculate, but if you look carefully you can tell the high and low points of the rim. Of course supposing that stereo data in JPL images is to be relied on.

Save the image and try it also south up!

[sranderson]

I don't know yet that we are seeing a large crater without much of a raised rim. How high does the rim for the crater in Arizona look from a mile away?

I remember driving to see the Barringer Crater in Arizona when I was a kid. It is fairly unimpressive from a distance. It looked like a row of hills, not the dramatic angled crater rim I expected. I revisited it when I was about 40 years old and it still did not look much like a crater from the road.

Scott