Per the rovers - the condition has been just about static for 7 sols.

Doug

Latest from Lemmon's site has Oppy down toAndSpirit, on the other hand, is up to 4.7 on 1265.

That sol 1243 Oppy measurement which is not based on array energy comes from these pancam observations, which are the first images from Oppy since sol 1235, if I'm keeping track correctly.

Does anyone know what, if any, effect these dust storms have on the local temperature swings? On Earth they are capable of both lowering the midday high temps ( by blocking the sun) as well as raising the overnight lows by preventing heat from radiating out into space.

As per the viking results posted earlier in this thread - it reduces the max, increase the min.

Doug

The TES on MGS measured temperatures and dust levels during the 2001 dust storm. On this page they note that atmospheric temperatures increased more than 20 degrees C.

Can the dust warming the atmosphere cause it to expand enough to reduce the lifetimes of the orbiters?

... and a complementary question, do we know if any of previous orbiters (Mars xxx, Mariner 9, V1 & V2) already hit the planet or when they'll do so ?

It sounds as if the atmospheric temperature effects of a dust storm are probably more complicated than they initially appeared. This article about the 2001 storm talks about the suspended dust warming the upper atmosphere while the planet's surface is chilled.



As for the possibility of an expanding atmosphere increasing the drag on orbiters, I'd guess there is at least some increase. Hopefully it is minor. That same article said the Mars Odyssey team was assuming it would impact their aerobraking maneuvers that were about to take place.

A few new details in this new press release:

That explains why we have a few new tau pancams from Oppy. That was one of the most informative releases in a while. Damn that settling dust.

Updated. Guessing the last two Oppy figures.

An update at space.com

http://www.space.com/news/070727_rovers_update.html

Estimates I've read suggest that Mariner 9 will come down in 2022, V1 and V2 orbiters in 2025, and MGS in 2046.

Here's the mp3 of todays NPR Science Friday interview with Jim Bell, discussing the storm (mixed in with a discussion about Phoenix with Dave Spencer)

Unfortunately, Flatow introduced it by saying that the current storm is "the worst dust storm ever recorded on the red planet" -- which is far from the truth, according to Mark Lemmon. It's the worst dust storm ever recorded by the rovers, perhaps, but as planetary storms go, it's not one of the biggest.

--Emily

slinted: Thanks for pointing out that entertaining broadcast.

Can anyone clue me in to the story behind the caller Brian's question about whether water on Mars was of the H2O or the HOH variety? Was the caller asking about free water, hydration water in minerals, or OH- radicals, or did he really think there are chemically different kinds of water?

I hate to say it, but that was not a terribly informative program.

The most recent MER PDS release included updated tau figures covering sols 1 - 1080 for both rovers. To put a little perspective on the current storm, here's the data from the first 1080 sols together with the current tau data from Mark Lemmon's page.

Opportunity:


Spirit:


Combined (please excuse the mess I made out of this one...there's a lot of data in there):


The y-axis is tau, using the 880nm data from the PDS. The x-axis is Ls (Solar Longitude...each Mars year is one 0-360 cycle). Since the rovers landed at nearly the end of a Mars year, the data actually begin with the short, purple line at the far right of each graph. Also, there is a gap during the current year between the end of the PDS data (sol 1079) and the beginning of Dr. Lemmon's storm coverage over on the dust devil page.

I wondered the same thing and then it hit me. I think this guy was using the term "water" as meaning ANY
molecular substance that is in the liquid phase. Under that definition the "water" might be liquid CO2, or liquid CH4, etc.

Craig

I had the same thought about alternatives as you described above as I listened to the program. Sadly there was no clarification to the caller Brian's question. But my impression (which may be completely wrong) was he thought there were chemically different forms of water. perhaps he was thinking about isotopes, D2O?

Slinted, this is quite an excellent compilation of the data, Thank you!

the point is well made !! although I am a bit color blind so its hard to see some lines. But that is of lesser importance. perhaps it would be helpful if you could add the seasons in the x-axis?

in fact I would like to use your graph in some upcoming Mars talks in the fall 2007 in Florida and the NE US.

thanks

ken

Ken,

There's no real need to relable the axis - Slinted's use of LS makes it straightforward.

LS=0 NH Spring\SH Autumn Equinox
LS=71 Martian Aphelion
LS=90 NH Summer\SH Winter Solstice
LS=180 NH Autumn\SH Spring Equinox
LS=251 Martian Perihelion
LS=270 NH Winter\SH Summer Solstice

More info here.

I've been off on vacations and now it's my time to read all that happened to our brave rovers during this period. Not too much, it looks, and I'm glad to know that they are in good shape.



Assuming no damage is detected as a result of this down-period, I have only two concerns for Opportunity:

1) Dust deposition on the solar arrays
2) I think we are still weeks from seeing her taking a dip into Duck Bay and the local season won't be the best one.

OT:


I use "rawid" (google for it) to extract the timestamps and other data from the filenames. But to make the things more convenient, I have a "rawid.bat" on my desktop containing just:

@rawid %1
@pause

You simply have to drop an image file on it and, voila, the results pop-up on a separate window.

Here is a false color view from Hubble (the filters to do true color were not available) on July 23, 2007.
It looks bad, but not as thick as 2001, which is in line with a lot of other reports.


Click to view attachment

Where'd you get the data?

--Emily

http://archive.stsci.edu/cgi-bin/proposal_...st&id=11314

I think the reason it was released right away was that the images were taken as a calibration activity for MARCI, and calibration images (understandably) generally don't get the year-long proprietary status.

Wow...thanks, Ted!

Yeah, it's still pretty bad. I dragged out the 'scope this morning & couldn't even see any dark surface markings with averted vision, just a little orange ball. Even here in downtown LA I can usually pick out something...but not today.

Oppy's still with us - she's sent home some navcams and pancams, including solar pancams for sols 1246 to 1249. We should soon have accurate taus for these sols.

Wow, the shadow is still very indistinct...but at least it's there.

Old image. It's from sol 1233.

Lemmon says Spirit has crept down to 4.2 on sol 1269, but Oppy has crept back up to 4.7 (1249). 4.7 is the highest we've been, as far as direct tau measurements (solar pancam) go.

The thought of dust accumulation is making me nervous. I wonder what array power levels are like recently. I'd think that the difference between what power your atmospheric model tells you you should receive based on the tau, and the actual measured array power should tell you how much dust is on the arrays. But there's got to be uncertainty there, since your model may get the indirect scattered light wrong at these high tau's.

I guess one way around this could be to do a series of shots of the sky in various directions to characterize the brightness of the scattered light. Probably not likely with power as tight as it is now.

Added more dots.

Doug

Since nobody seems to have picked up on these I thought I'd point out the visualizations of recent tau images (animations and multiple images) from both rovers that I posted today. Jim kindly provided me with RADs to work with so the calibration is correct. There have been more tau images since I got these from Jim, so these are a few days old, but still interesting...



Spirit


Opportunity


--Emily

Emily,
I did see your very nice updated work this afternoon and the earlier version. In fact I'd like to use them at several talks I'm presenting soon in Florida and the NY area. The animations and graphs will help tell a vivid adventure story. thank you. ken

Oh, you'd better believe we notice. I sort of just assume everyone else hits up your blog each day. In this instance, the visuals are very impressive.

We noticed your work, Emily. Anyone who is anyone has an rss link to your blog on their home page. The visitor location map is a nice addition, too.

In case some were wondering where the rovers were in the midst of this storm, here is a crude attempt to align the MARCI map to THEMIS.
Click to view attachment

Good assumption.

Emily
fantastic way to make the changes easy to interpret.

OK, noted Sorry to be redundant!

--Emily

Here's an awesome graph showing tau seasonal comparisons for Viking and MER (from Dr. Lemmon's website).

I think what's striking is the correlation of this year's MER data to the previous year, and then comes the dust storm...

The current storm and the major Viking storm also correlate in starting about Ls 270. If the current storm follows the graph, then tau should be below 1.5 in about 25 sols. Hopefully we will be good by the end of August.

I get around 50 sols, until Ls = 320 or so when the Viking storm ended. Did you use the number of days in an earth year instead of sols in a mars year?

Anyway, it sounds like these storms vary a lot, so we can hope it'll end sooner, and pray it doesn't end much later...

Some discouraging news for Oppy. Lots of details about low energy procedures in this update.

Emily, everyone on this forum checks your blog multiple times a day.
Great visualizations...... thanks for all the hard work you do!!! We all appreciate it.

Yeah, fredk,,, that last update is scary..... but these rovers have proven mighty hard to shut down.
Ain't over yet.

Craig

Well, that wasn't the greatest news, was it?

Don't worry.
Be Happy.

Even if these overachieving rovers meet their doom in this Martian weather, they've returned data about more amazing discoveries than anyone could have ever expected. We are at least an order of magnitude beyond what any reasonable person could have confidently expected from them, and we should see the next Mars explorer to launch in a few days. What more could you ask for?

We can see from that update that the MER team is on top of the situation. For the other optimists out there, that interesting correlation Pando posted from Dr. Lemmon's site suggests we can hope for a future improvement. I wouldn't write these robotic explorers off, just yet.

I wouldn't write these rovers off just yet either. Just because they are approaching the lower temperature limit for safety does not mean we are going to lose the rover. It's possible that they will still survive intact. It's also possible that they will survive but minus some instrumentation. What parts are likely to blow? I don't know. But I doubt we would lose the whole rover.

I may be wrong, but the way I read that part was that the threat was being power negative, that the heaters would still come on as long as they could....

Not sure which is the bigger threat - damage from freezing or damage from battery depletion.

A rover with a depleted battery can still wake up when it's electronics are still intact
A rover with a broken processor is dead.

I wonder how cold the core can get before real damage occurs. There's probably a quit large margin between the trigger temp of the heaters (-40 c) and the temp that makes silicon and conductors non functional. We're used to more examples of unbelievable durability and surprises of survival capabilities of the hardware.....

Can't sleep......

As I understand it, the problem isn't that the electronics stops working if it gets too cold - it's that thermal contraction may physically break PCB traces, soldered connections etc. (Quick edit to say - no idea what that temperature might be but presumably at design time you put the "emergency life-saver" heaters as close as you can the the lowest certified operating temperature for those systems. Of course there's no knowing how over-spec'd they may turn out to be...)

Yeah, thermal contraction of the physical circuits is what I thought they were concerned about.

We got another Themis 9 micron opacity map today. Although I can see some improvement in the latest image, it appears that this storm is still quite dynamic, and not obviously dying out. This is a little animation of the 3 most recent Themis maps. Opportunity is the yellow dot near the center, and Spirit is near the yellow dot on the far right side. About all most of us can do at this point is keep our fingers crossed.

Click to view attachment