Agreed, I think West of Porcupine is slightly more favorable terrain but both options will mean zigzagging a bit to avoid bad spots. This might mean driving backwards until close to Porcupine, then passing that area driving forward on autonav, and turning backwards again south of Porcupine.



Yes, but I think it is significant that the RF wheel gear problems started again during those days!

The forward wheels take the most stress from driving in sand, as they 'dig' the trench in which the other wheels are following. I'm afraid driving in sand is not good for the gears and that's why I'm reluctant to leave the bedrock (although you can't avoid leaving it in the end).

'Dust traps' are nasty items to spot mathematically, I didn't include my 'dust filter' maps in the earlier post as they might be misleading. It is hard to say where you have to place the 'red' marker on those maps, the 'fingerprint' method I'm using now for the terrain calculations relies heavily on historical data (collected by you, of which I'm very grateful). The software attempts to match the terrain with past history and this is how the color-designations are created on all the maps. For dunes/craters/bedrock there is sufficient data but with dusttraps we (fortunately) don't know 'how much she can take', so the maps for dust tend to be overly pessimistic and red area's can often be crossed with no problem. Still, I don't want to find out what is the exact limit for 'red'...



I fully agree that she can easily 'take' the cross-dune east portion (on my above maps it shows green with only isolated blue spots), but I'm worried how much stress driving for 1 km in such terrain will be for the gears...

Well, fortunately we are only sitting in the backseat, I'm very interested what the true drivers will decide, guess we will find out soon enough..

Kind regards,

Geert.

I would rather take 200 straight "boring" driving Sols in a row, if this increased the chance to reach Endeavour and spent whatever remains from the science hardware there,
because that's where the most exciting science stuff waits, IMHO :wheel

Is that the one I can only refer to as "Midway"? She's plumb centre here.

Andy

Click to view attachment

Terrain overview map of the Porcupine region with some of the possible routes through.

Green is normal driving, blue is suspect area, red is danger.

Regards,

Geert.

That whole lower section looks interesting. Craters of all sizes and various stages of erosion.

Any word on when the next drive will be? How's the wheel current? Am I too impatient?

That one I CAN answer.

Are they still dealing with that dodgy wheel?

Either that or a stop to do some pancam science. IMHO probably both.
No drive was planned during the whole week.

There have been a number of PANCAM images of the rover's wheel tracks taken in the past few days, using all the camera's available filters. I assume these are scientific in nature. To my untrained eye, the bright material is reminiscent of the silica found by Spirit at HP. Any thoughts?

Or are the pictures diagnostic, part of the analysis of the RF wheel?

No, They are loading a new SW patch. Probably the last FSW ptch on the rovers.

Considering the amazing longevity of these magnificent rovers, how can you suggest that this most recent update will be the last?

Paolo, a bit OT here, but do you know if any of the MER code will be reused on MSL (or adapted for same)? Have seen a lot of this on modern airplanes.

That's what I have been told. This update was necessary since hardcoded in theSW there was a limit of 2010 as date relative to commands. Any command dated past 2010 would have been refused.

We might upload some small patched to be able to overcome malfunctions or loss of HW, but I do not believe there will be any significant change in the flight SW.

Paolo

Yes. Lots of commands and sw will be reused. Some of the ground tools as well.

Paolo

At the time this code was written who would believe such a limit could be reached!!!

In another topic, just checked the imaging plan and sol 1813, that is today, is planned for driving.

There has got to be a work-around solution. Is is possible to roll back the clocks on the rovers with a carefully written routine to adress the host of other issues likely to arise? (as long as it's uploaded by 2010 )

The workaround is the patch that has been loaded on Opportunity (for now). This new version of the FSW now can accept commands past 2010. Now we have to start thinking about how to fix the next time restriction due to Unix and Linux timespec. ;-)

Paolo

that will be 2038. but before this happens, we will hit the limit of the space-clock counter in the MER file names, the last navigation camera image being something like 1N999999999... on Sol 9821, Tue. 09. 09. 2031 ... approx. seven years before the UNIX time_t overflow

I forgot about that. In either case I believe it will be someone else's problem as I will be retired by then (hopefully).

Paolo.

This has been an interesting subtopic.

No kidding, who would have guessed? Who could have guessed? Let's hope the coders of future exploratory missions are encouraged to be somewhat more optimistic.

If I am fortunate enough to remain sentient until those years, I'll be either 81 or 88 years old.

Excuse me. I have to poll one or more of my various sensors, and report back.

If the rovers are still working by 2031 there'll hopefully be people on Mars more than happy to PUSH them around!

The limit of 2010 was a safety measure in order to prevent execution of commands that were received in error. Besides error correction code, there are some additional safety cross checks in place and this was one of them. 2010 *was* a very, very optimistic date at that time. ;-)

Paolo

Steve Squyres thinks that Oppy could drive 12 km over 2 years. I estimate that by 2031 Oppy will have travelled another 132 km. Oppy will easily reach the Miyamoto MSL landing site by then. Endeavour and Miyamoto are both visible in Tedstryk's Mariner 6 mosaic:

http://www.unmannedspaceflight.com/index.p...st&id=15664

On a more serious note, what are the plans when Oppy has reached Endeavour? Is there a plan to drive to the interesting hills on the South East side of Endeavour? Are there plans to drive down to the floor of Endeavour?

Just supposing both MER rovers will still be active by the time MSL lands, how much load will that put on the ground-teams, SS has once commented that operating two rovers at the same time could be quite tough, would it be possible to operate 3 rovers at the same time? (Having in mind also comm-passes and relay capacity of the orbiters, DSN availability, etc).

I suppose the landing-location of MSL will be very important in this aspect, if it lands "close" to one of the MER rovers this will be harder on the relay?

Regards,

Geert.

There have been rumors on where they want to go. I believe the North or South rim will be first. We'll see what the terrain and slopes are like inside Endeavour, it might be they are to difficult to traverse.

Paolo

The quirks of each rover has makes MER two separate missions already. The command set is the same, but the way we operate the
two rovers is so different that there is very little common ground. Stepping from one rover to the next will be difficult for sure, but not unmanageable. I'm not sure if they are going to ask to drive either one of the missions exclusively. I hope not.



My hope that at least this time they will select a different Rx/Tx frequency and avoid the conflict we have between MRO and MERA ;-)

Paolo

Time for another "reading the tea leaves" post.

The new Planetary Society story states:

Here's a sketch of the projected route based on these comments:
Click to view attachment
It looks basically like "follow the exposed bedrock southish until it ends, then turn to the east."

This decision still puzzles me. If we continue on this heading (SSW) we will be facing a quite big dune area in a question of 2km or so.
Do we have HiRISE coverage of the area SSW of the current position for the next 7km?

I do not recall the distances exactly, but we will still be heading SW-SSW for about 2-3Km then we should be able to start heading back ESE-SE. The entire path is visible in the HiRISE strips that we have collected so far.

Paolo

Curios about the wheel motor current. How much higher is it above normal? What is the normal current draw for a wheel motor? How's it looking driving backwards now? Thanks

The currents depend on soil type, slope (only a bit) but in this specific instance (MER-B Sol 1787) all wheel currents were around 0.2-0.25A while the RF wheel was around 0.5-0.55A. These motors can take 1A continuous, so there is ample margin, but it is the fact we had never seen such a large discrepancy (0.1-0.2A difference had been seen before).

Paolo

Can it be that difficult? Just hand UMSF a rover manual and we will take over the day to day running of the MERs when MSL lands... We have plenty of experience by now...

I've been a bit out of the loop recently, learning how to be a parent! However I think I've mastered the important 'hold baby in one arm while using the other to process MER images' technique.

Cobble survey from sol 1811



James

James, the correct (Martian) way to do this is to hold the baby in one arm, use another arm to process MER images, and use the other arm to...

You don't know how you've been missed James!

Hope all the three of you are doing great there on good old mother earth, here on Mars I was impacient for your return, now it is time to name a little crater after...well...you know who...

Paolo,
I was just wondering, how are the engineering testbed rovers holding out? Do they need to get their motors replaced regularly? Any odometer on them measuring how far they've gone?

We have only one real testbed, and the actuators are holding up quite well but it has not been used as extensively as the real rovers (we do not keep track of the wheel odometry on that one) and the environment is quite a cozy stable 20C 24/7, so I don't think it counts as comparison data point ;-)

Paolo

Oppy on HIRISE.

http://hirise.lpl.arizona.edu/ESP_011765_1780

Cheers
PAC

Very cool. This was right after she buzzed by Ranger and Surveyor I believe.

I also think we saw a short drive yesterday, about 35m to the SSW. Can someone verify?

This deserves an inline post:



Sol 1783 : January 29, 2009

Correct. Sol 1816 ~40m SSW from a quick check of the tracking data

And you can see her tracks, too!
Click to view attachment
(tracks indicated by yellow arrows)

-Mike

That puts us somewhere around here:
Click to view attachment
(ustrax's machiavelic laugh can be heard over at Meridiani...)

Where are you Tesheiner?

Come on Oppy! Two weeks to reach Porcupine, I bet you'll do it!

Amazing HiRISE image btw...you can clearly see the mast shadow...I think...

What's amazing is how hard the tracks are to see in most of the HiRISE image - I can see some leaving Victoria - then they go - then I can pick them up for the last few metres.

Rui, any chance of seeing those incriminating photos you have of Paolo and the other drivers? They are clearly under your control.

Brian...here's Paolo's prima colazione...

Still here, but I'm a bit busy this whole week.

We don't know at which point around Endeavour's rim Oppy will "arrive" - but we have the next best thing..!
Click to view attachment *
Tell us, o mage -- whereabouts on your predicted route map is your definition of "arrival at Endeavour"?

* this one's dedicated to anyone who doubts their abilities with graphics software - see! someone's FAR more inept than you are...!

I did a comparision between Opportunity in this latest HiRISE image with a picture I use internally to "fine-tune" the rover's position at a given site/sol in the map. What I usually do once the post-drive navcam images are available is to create a mosaic in polar projection and attempt to registrate it in this "map" I keep internally at full (25cm/pix) resolution.
Click to view attachment

I added the map-projected picture with the rover as a semi-transparent layer trying to match the background of both images and here's the result. Not bad.
Click to view attachment

Click to view attachment (animated GIF)