That's a new milestone! (but before others notice it, please correct your red labbeling on VC's near rim: it's NOT the Beacon)

Isn't it amazing - we are so close to Victoria Crater now, almost the range of Eagle to Endurance....but we can essentially see NOTHING of it.

Doug

So very true. Our beloved Vicky is an old, old crone. Worn flat over however many millions of years; her once upright, sprightly rim eroded back into crenulations and undermined until it sags down into her nether regions. So we can't even see the immediate near rim ( with the possible exception of the Beacon slab). Rim depressions like the Boat Ramp are below our sight horizon.
An old lady, but one who might tell us some secrets about Mars' past, long before her flaming youth.

Heh -- I'm still waiting for the "hell of a view"! Granted that Opportunity's had a good view out to the horizon for a while, it's still not everything-visible panorama I expected. The land's too flat and the horizon too close, I guess.

About the horizon, it seems we have the false impression that it corresponds to the near rim but it's actually a fair distance of that rim.

I made the following composition from pancams taken on sols 855 and 864. Beacon aside, there are some dark features which can be seen on both shots and there is clearly a parallax effect due to the rover's movement towards BC. Given the beacon at the near rim, obviously those dark features are not very near the rim. The leftmost dark feature is quite at the horizon line and that's what convinced me that we are actually not seeing the near rim except for the beacon.

Click to view attachment

The truth will be that the Beacon is stranger than strange. I'd propose that it _ought_ to be named "Escher" because of the optical illusion property! Except that name has been used before.

Victoria is indeed strange. A flat ejecta blanket, no appreciable outside rim (with the exception of that enigma) above the ejecta blanket so it won't be visible until we are virtually upon it. Endurance at least had some rim above the plain, Erebus had the "Dunefield" and the Payson bluff but Victoria is stealthy...

--Bill

Bill:

Is it possible that somebody has stolen it? Ustrax was previously in the frame for the Ultreya Heist...

Hmmm...

Bob Shaw

I think we'll be *very* close to Victoria until we see the ground open up in front of the rover, and we'll say "holy $#!%"! Looking at the satellite images Vicky's pretty deep. It will be quite a sight when Oppy will be perched on one of the triangular rim remnants looking into the hole.

Sol 866 (today) and 867 (Sunday) there will not be any driving. Oppy will just by observing the sky.




Rodolfo

Taking advantage of the long weekend to finish downloading the software update?

> Taking advantage of the long weekend to finish downloading the software update?

Not necessarily given that different antennas are used for sw/commands uplink (HGA) and for data downlink (UHF).

> Sol 866 (today) and 867 (Sunday) there will not be any driving. Oppy will just by observing the sky.

I think the main reason for this lack of new sequences is to give a chance for less priority data still on the rover to be downlinked.

I can't help but wonder, "How the blazes are we going to draw accurate route maps once on the apron?" Unless we are sent that postulated MRO image of the region by the gods above, we'll all be squinting pretty hard to find navigational markers to correlate to the MOC image. I have no doubt that we'll finally refine a process, but does anyone have a plan? Mine's pretty rough...

They can also do uplink via UHF now as well - but there's a long lead time for getting the data ready to send as it has to go up on whichever uplink to Odyssey is before the UHF pass, and it can be 24 hrs or more.

Charge batteries, downlink some lower priority mid-drive imaging (such as a sol 812 and sol 856 L1 albedo pan), , do some more flight software uplinks, all good stuff.

Doug

My guess, Tom, is that we will be making good guesstimates based on direction and odometry. Being very flat, I'd reckon that waypoints would be easily visible. Being a very firm surface, I'd suppose that wheel slip would approach zero. Advanced WAGs, in other words.

--Bill

Tom! Repent! Thank the Good Lord for THE BEACON!
With that, Beagle, the smaller apron craters, and other landmarks we haven't seen yet, the apron will be Triangulation CITY! . I expect Tesh, Dilo, Rod, Ustrax, fredk...hell, I might even take a whack at it... should be able to calculate our position to about 2.5 gnat's eyelashes. Of course there won't be slabs of evaporite to sit on and positively identify from orbit, but sooner or later we have to learn to trust the geometry! This may be a struggle for the Far-rimmers, but it's my fervent hope that the sight of that glittering, white slab of evaporite perched up there on the near rim will at last free them from the shackles of....of... abdominal intuition.
Brothers, let us pray.

One of the things you first learn about geometry and trigonometry is that common points between two calculations must be just that, points. Different points along a wall that appear to be the same point source from different perspectives will really throw your calculations out of whack.

So I am now forced to wonder. If we are going to use the conclusion-jumping trigonometry practiced by the near rimmers to navigate Opportunity up the ejecta blanket and to the precipice of this massive crater , did JPL do any roll and tumble tests on the MER craft?

At the Pancam database, I have found many pending pictures from past soles to be downlinked to Earth. As the MER is getting a new uploaded mobility software, I seems that it is wise to clean all memory of kept past pictures just in the case before upgrading a new version of Mobility software. This will avoid that any problems related with the upgrad might loose any remain pictures in the board.

Rodolfo

I would try a similar aproach as for Spirit.
You must find similar features (e.g. rocks) on both pre and post-drive images and calculate the net driving distance using any Parallax Calculator. For the driving heading I would take the beacon as a reference.
This approach, together with periodic corrections (if possible), worked quite well for Spirit's route map.

BTW, when I say "I would" is because I will probably have no time to do that. My summer vacations starts on Jul 15th and I'm quite sure by that time we will still be at Beagle Crater.

It would have been fascinating to see you navigate the MERs to Mars, Dan'l.

Next drive will be on sol 869

Yes, we should have no problem measuring distance with parallax as usual, and we can even get pretty good directional from the tracking site. I'd use MMB for that, since it displays the azimuth and elevation as you pan around in panorama mode. That's all you need to plot a path. But the point I was making is that small errors will accumulate. Outside of the apron we have been able to see the shapes of ripples and patches of outcrop that can be directly correlated to the MOC imagery. If distance and direction do not quite plot the correct point, it is obvious when comparing the rover's images of it's surroundings to the MOC image.

I wouldn't call the apron as seen from the MOC featureless, but there are not very many features on it. Without a visual corelation between the orbital and rover images, those accumulated errors will not be apparent. It is not a big problem, since there are only a few hundred meters between the bottom and the rim. Once at the rim there should be plenty of landmarks.

[quote name='jamescanvin' date='Jul 3 2006, 01:42 AM' post='60497']
Next drive will be on sol 869

Yikes, nearly a week without any progress towards Victoria/Beagle.

Independance Day weekend. Recharge, downlink, flight software uplink, targetted remote sensing. Busy rovers, but a bit of time off for mission people. (After the sprint from Erebus to here, and the Purgatory 2 situation...I think they're entitled)

Doug

Yup, same as for Spirit's map.
A possible solution would be to make use of those little craters seen on the apron as heading references and triangulate the aprox. rover's position based on them. This method wouldn't suffer of accumulated errors, but it's accuracy is questionable. It could be used from time to time to adjust the already plotted route.

Maybe, the best approach would be to trust 100% on the data tracking web data until the rover makes about 80% of the path to the rim. At that point, triangulation and/or parallax could be used to calculate the "exact" rover's position and to re-adjust the route.

Route map, updated after sol 869 driving.

Click to view attachment

If I got it right from the pancam database, the rover is now on an outcrop named "Fort Gibson".

Is the plan that Opportunity will continue through the dune troughs for another 70 or 80 meters, and then make a hard left for the Corner on the terrain with apparantly more exposed Epsom salts?

To my untrained eye, the path straight toward Beagle looks so tempting right now. The ripples look very low and traversable, maybe 5-6 to cross to get to that first outcrop.

http://marsrovers.jpl.nasa.gov/gallery/all...U6P1948R0M1.JPG

In the following shot along the current heading, the ripples seem higher and more potentially troublesome.

http://marsrovers.jpl.nasa.gov/gallery/all...U6P1948R0M1.JPG

Brian

Er, I measure 50 meters movement for sol 869. The "fort" I think is the small outcrop spot about 13 meters further south.

Rover motion data from the tracking web say 35m, like parallax. Off course, parallax measurements depends on the feature you guess to be the one corresponding to the current position.
Do you use another technic?

Better wait for the north-looking navcam pics (planned for sol 870) to fine tune this position.

Today, Sol 870 is another driving day!


Due to the orientation of Navcam (between 162 to 342), the guessed route are two (right hand - blue) and (left hand - yellow). I would rather choose the route blue.

Click to view attachment

Rodolfo

Route map, updated up to sol 870.

Click to view attachment

They took the green path, Rodolfo.

Greetings: I am a new member of the forum. but a long time visitor. Just wanted to say that I have really enjoyed the graphics and discussions you guys have put together.... Tesheiner's maps are amazing!
Can't wait until Oppy arrives at Corner Crater! - Sacramento Bob

Welcome to the forum Bob!

Welcome neighbor

I think Sacramentans need their own topic Btw, I'm a relatively new member, my name is Bob, and I am in East Sacramento!

Enough with the Bobs, already!

Bob Shaw

Updated route map (sol 871).

Click to view attachment

Looks like within a week the rover should be at or past Beagle. Hopefully, the dark layer around Victoria is easily negotiated by Opportunity. If it is then I'm guessing around the end of August Oppy will be at the rim.

I'll speculate that the drivers will be nervous about the sandpile ahead of Oppy and take a detour...

--Bill

Yep. Well, at least some of us are nervous. I am beginning to suspect that they drove to this point intentionally. It seems to be the end of the maze in some ways. A turn to the left or right seems a logical thing to do. It doesn't appear that we'll see a move on 872.

No, looks like it's a spring cleaning sol!



Sol 400's!

Driving again on Sol 873 though.



James

I too was concerned about the mound ahead, but the drivers may have something else in mind as they are deliberately driving straight at it, according to Tesh's map. Since recent rear Hazcams show good traction over the last dune crest, maybe they are confident about ground conditions and plan to surmount the mound as a viewpoint?
We'll see....

Kenny

This is almost more drama than "who shot JR". We'll wait, we'll see.

Attached is a clip from MOC image R1500822, enhanced to bring out low-contrast detail and presented in .PNG format so there isn't JPEG artifacting. For general membership use to see what's ahead on the ejecta apron. The solar azimuth was 9.5 deg, the solar altitude was 64.9 degrees.

--Bill

As long as the rover drivers aren't fans of Thelma and Louise....

Mind if we call you "Bruce" then to keep it clear?

Was that posting spam, then?

Spam, spam, spam.

Spam.

Bob Shaw

The 873 navcams will be centered on 126 degrees, which is a bit east of the 871 set, but none of the new images are down yet. It will be interesting to see where the drive direction pancams are located. We may get pancams of Beagle and the Beacon shortly.

Updated route map (sol 873)

Click to view attachment