And here's the reference for that news.

@marsroverdriver (Should be careful here: #FreeSpirit progress on Mars -- actual motion vs. commanded motion -- is right on predicts. Almost scary.)

good (cautious) news from twitter

Huh. Swear I just heard a sound like hundreds of thousands of fingers crossing...

Four Steps.

Click to view attachment

Here is a Spirit undercarriage animation that spans sols 2081, 88, 90, 92, and 2095
It shows the center view... the JPL engineers have been taking, what I call, a left, center, and right view of the underbelly after drives. Incredibly, the IDD arm places the MI at the exact same place (+/- a pixel or two) over 2 weeks.
I have tortured the histograms to get the lighting bearable.
If anyone wants to try a Lucy-Richardson or any other focusing trick, I can provide the the individual processed frames via flickr.

Click to view attachment

Cheers

...is right on predicts? ...is right on predicts???

Might he mean, "...is right on predictions?" Where is our language going these days?

Just making the verb predict more like the verb target.

Scott's a Martian mate...

I've always heard 'predicts' used rather than 'predictions' in space ops.

Full in-line quoting removed. That certainly ISN'T right - ADMIN

And that somehow makes it right?

I'd rather it be spaceflight ops -- I mean operations -- jargon than twitterese!

Lots of professional jargon has not made it into the dictionary. You want behind the scenes info (I mean information) but not behind the scenes lingo (I mean language)?

Yes.

If you want to have a pathetic argument about language and the lexicon of space-ops, find another forum.

While we're playing pedant, you might want to stop breaching forum etiquette via full in-line quoting.

Does any of you have insight into the next moves of the rover extraction team at JPL. What do they expect from the next drive.. and the whatifs that must have been planned in detail ?

Not knowing what action plans is made, is no fun at all.

From NASA MER Site 25 Nov - "The cumulative results from Sols 2088 to 2095 (Nov. 17 to 24) are 8.1 meters (27 feet) of commanded motion, 15.7 millimeters (0.6 inch) of forward progress, 9.9 millimeters (0.4 inch) of movement to the left, and 4.8 millimeters (0.2 inch) of sinkage"

This is pretty much as predicted......

My qs -
1- How many mms until sinkage starts to become critical?
2 -At what rate can we afford to sink in proportion to foward movement?

Anyone got any comments or ideas?

More of the same - moderate driven commands (5 metres) with very very small progress ( 5-10 mm )

Essentially - we're looking at a 99.5+% slip rate - but it's still progress.


It looks to me as if the belly-rock is shifting with the rover, so as that shifts we may have more 'headroom' for sinkage whilst making progress.

Not exactly what you are after, but Scott Maxwell tweeted
How critical sinking might be depends on the nature of Belly Rock.

So, Scott says we're ~50cm from clearing Belly Rock. How many more cm we'll we need to see Belly Rock appears in Rear Hazcam?

50cm. The bottom of a Hazcam image is the ground directly below it So we will see the rock appear at the bottom of Hazcams as we get clear of it. Hazcam's FOV is 120 degrees and the pointing is 30 degrees below the horizon - so you get 90 degrees below, and 30 degrees above.

Does Spirit sink at all during the days off?

I'm just glad I'm not driving her -- I'd be spinning those wheels in a mad panic, hehe.

I think the sinking rate is more critical than what is discussed, focusing on Belly Rock. The NASA team must surely have a sink/progress ratio maximum that must lead to an alternative strategy. My experience from driving in snow (may not apply at all, but...) is that traction is always better in the places where your wheels havent been. The pictures shows that the piles of sand ahead of the wheels most likely is less compact than the untouched areas (volume). So one can wonder WHEN WILL THEY TURN THE WEELS LEFT??

Please post your favorite alterative strategies, given the current results.

One tidbit I remember from the press briefing was John Callas saying that they now treat sinkage as a "consumable" (much like power or flash memory), so it's something they're monitoring very closely. He said something about how it would be "game over" if they sank so much that the belly pan was sitting flat on the ground. Awful image!

Since we've sunk about 5 mm in these drives, that does suggest Belly Rock is being pushed down too, which would be very good news. And if I squint at PDP's excellent MI animations, I can just imagine that I can see it getting pushed down. But it's still not entirely clear, since we don't know how far along Spirit's belly the rock is. One end of Spirit might be pivoting down and the other held up by the rock.

I have to say that the post by Maxwell that we need 50 cm to clear Belly Rock baffled me. The entire underbelly is only about 60 cm from front to back. So if he meant that we need 50 cm of movement to clear the belly, then the rock had to be around 10 cm from the front initially. But it looked like it was much farther back in the MI's. Maybe he meant we need 50 cm to clear the rear wheels. That would put the rock at something like 40 cm from the front of the belly, and behind the centre of mass, which would make much more sense.

Unfortunately left gets us deeper into Scamander crater and presumably more of the light fluffy stuff. Right now we have better traction on the right wheels (outside the crater) which we don't want to lose...

Or about 20cm from clearing the belly? Also, the rock extends farther back than its contact point with Spirit. We should begin to see it with the rear hazcam even before it disengages from the belly. Maybe just five or ten more cm?

I see this drive as a control, or baseline drive.

The last couple drives have involved fine tuned maneuvers, with individual wheel adjustments. The next drive is straight ahead with all wheels the same (except the RF of course). This eliminates individual wheel adjustment variables so any rover movement will be only the result of its interaction with the terrain. I expect information from this drive will be used to determine what wheel adjustments will be needed on future drives.

I'm a glass-half-empty sort of chap...



Does anyone know if those are /per-drive/ predictions? I took the meaning "...the predictions from the sandbox studies, which suggest success is by no means certain, and this is scary because it looks like Spirit's permanently stuck".

Clearly it's all about the sink rate, for now at least.. A ratio of forward to downward progress of 3:2 doesn't sound very hopeful. Perhaps the left-hand wheels will eventually dig down to the rock of the hidden crater rim, and gain traction...

On the bright side, with a few mm progress per drive, the final (hopefully very long) animation from the front hazcams will look nice and smooth :>

Actually, we have already seen what's below the rear end of the belly. On sols 1871 and 1886 we were a bit farther north of our current location, so the rear hazcams from those sols show what's currently invisible under the rear belly. In this mosaic I've identified two groups of rocks in each frame, and circled one group in white and the other in black. In the current (2095) view, the black-circled rocks are just visible. From the 1886 frame we can see that we'll see a few smallish rocks first before Belly Rock.

Click to view attachment

The 1871 view is really interesting. In that frame I've circled two new groups of rocks in grey (the farther of these groups is also visible at the bottom of the 1886 frame). I've identified those grey-circled groups in the sol 1870 navcam anaglyph view, and again circled them in grey:

Click to view attachment

Also on this navcam view, I've circled my identification of Belly Rock in white. Looking back at the 1871 hazcam view, it looks like the LR wheel was actually sitting on part of Belly Rock! So it looks like we did drive over Belly Rock, and hopefully loosened it up as well.

Oh, don't overthink the "almost scary" business. Scott's a typical engineer, always expecting the worst and obsessively hunting for the mistakes and errors he KNOWS have to be in there somewhere. If things are going well, that just means he hasn't caught the mistake he must have made! He'll be sure he's wrong until Spirit's out of there safely. And then he'll find something else to worry about.

Reading "Mars & Me", I understand perfectly what you mean. Nice analyse

Long time since I have posted in the Thread or any other one.
I am still sick with a thyroid issue and being treated now for it.
Hopefully soon I will be better.

Back to the topic at hand. I have heard people discussing using
the arm with all the tools to lift the rover up a little. Has anyone ever
thought about using the grinder tool part that is not working anymore
as a plow to move some of the dirt, sand or what ever it is in front
of that one wheel? If they did that would that be less resistance on
that front wheel making it easier for it to get a grip? I think it's worth a
shot. Is there any small rocks we can shove in front of that wheel also so
it has a solid surface to grab onto???

Just me thinking of other things we can do to help Spirit out

Bobby

What I was trying to get at is if Belly Rock is firmly embedded, that would be the first thing they hit. If it's not, sinking is still a problem, but the acceptable limit must be larger.

My favorite strategy is for the people who have spent the last five years driving the rovers, and last several months studying the problem do what they do best.

I take Scott Maxwells "almost scary" to mean "wow this is amazingly close to what we predicted" not anything to do with fear. The following tweet is also relevent


Bobby:
The rover team is full of smart, creative people who know their vehicle extremely well. If there's anything to be done with the arm, they've thought about it. However, they have consistently said the arm is not well suited to this and would only be used as a last resort. This is covered in the FAQ thread http://www.unmannedspaceflight.com/index.php?showtopic=6085
Best wishes on your personal recovery.

Yes, precisely, as Emily explained. Just to amplify, phrases like "almost scary" in this context are used in current US slang to mean exactly what you stated, Reed.

US English slang of this type tends to accentuate opposites (often sarcastically), while UK English slang in the same vein tends towards understatement. I'll let everyone know when it all changes in the US again in six months or so...

Given the many unknowns and an uncannily accurate prediction, I would say that "almost scary" also alludes, sarcastically, to a supernatural component such as clairvoyance.

According to the tracking site the next drive is sol 2099.

Here is an underbelly image from Sol 2061 (before extrication maneuvers)
There is a before and after image
I rotated the 'after' to have a level under-deck.
I don't think belly rock is touching (I wish I could be sure!)
oh well, just waiting for the next drive (Sol 2099)
Your mileage may vary

Click to view attachment Click to view attachment

Cheers

Very little apparent movement from today’s drive. On a related note, how are you guys getting Spirits movement from the tracking site?

Yes, looking at the forward and rear hazcams it looks like Spirit just pivoted ever so slightly clockwise around the RF wheel which did not slide at all.
Should Spirit continue to try to move forward (which may just cause more pivoting around that wheel), or should she back up a bit and try then pushing forward again to get the RF sliding again? I guess we will just wait and see what they try next...

Minimal movement, indeed. Besides, only one step was executed not two; my guess is that it was somehow aborted.

On another note, today is sol 2100!
Click to view attachment

If Spirit could pivot all the way around the RF wheel, it would be out of the crater and facing in the opposite direction. At that point it could just drive backward dragging the wheel again. So maybe pivoting is not so bad.

Wow, this is just a nail-biter to wait for news each day. Let me see if I can summarize the action for those of us who've missed a few days of news due to holidays.

Short term goal: move forward 50 cm to clear Belly Rock.
Long term goal: move forward ~1m to escape Troy?

Update for Sol 2095 (Nov 24th)
Total commanded movement since Sol 2088 (Nov 17): 8.1 m
Total successfully processed movement (wheel spin): 5.6 m

Total forward movement: 15.7 mm
Total sinkage: 4.8 mm

Perhaps it's meaningless to project with just 2 datapoints, but if this ratio of motion is maintained, then to clear Belly Rock Spirit must churn about 178m of wheel spinning and could sink 150mm!

It is similar to the 192m of wheel turns it took to move 1m to get out of purgatory

Some people have very short memories

I wouldn't call that "short term goal" but "medium term" or even "long term".
The short term goal is, IMO, keep making a steady progress.

Was there any sinkage reported during the purgatory extraction?

Here is the underbelly MI animation from Sols 2081, 88, 90, 92, 95, 2099 (center MI view)
There is minor movement on 2099 as commented before.

Click to view attachment

Cheers

In case you haven't seen, Odyssey's in Safe mode again
http://www.jpl.nasa.gov/news/news.cfm?rele...FeaturesHome%27

Wondered how this would affect extraction Got this reply from Scott on Twitter last night

"Unclear. Possibly no effect: they might be out of safe mode by the next time we can try to #FreeSpirit anyway (Wednesday)."

Five steps.

I sure hope that stuck wheel starts to slide.

Click to view attachment

The reversion from the last frame to the first shows clearly that it already is. It's not moving as much as the FL - but it IS moving.

Also, if the wheels are moving material from in front of them to behind them they are doing something very useful. There might be no motion for ten drives while stuff is moved by the wheels, then suddenly you get a bit of a move, and that sequence is repeated as often as necessary.

Phil