Oh no...This is getting bad:
The new and potentially bleak outlook is a stark shift from the prognosis earlier this week.
The dusty squall has reduced direct sunlight to Mars' surface by nearly 99 percent, an unprecedented threat for the solar-powered robotic explorers. If the storm keeps up and thickens with even more dust, officials fear the rovers' batteries may empty and silence the robotic explorers forever.
Opportunity's energy-gathering ability has been slashed to a dangerous 280 watt-hours-enough power to light only three 90-watt light bulbs.
"The worst-case scenario is that enough dust in the sky decreases solar energy to the point that we have to shut down too many things to save power," Lemmon said. "The rovers keep their battery alive by keeping their electronics alive."
"The reality of the situation is that we're limited as to what we can do from the ground by cutting power use," Callas said. "If it continues to worsen and stay that way, it's a survivability issue for Opportunity. If Mars wants to kill the rovers, it can."
http://www.space.com/news/070705_dusty_rovers.html
This is starting to look like it might need it's own topic.
http://www.space.com/news/070705_dusty_rovers.html
With Home plate and the inside of Victoria on the menu I really hope this blows over.
99% drop in direct beam flux is Tau of around 5.2. That's slightly worse than the highest Tau levels measured by the Vikings in 1977.
Edited. Doh! My bad - it's actually about 4.6 which is not quite as bad as the worst the Viking's saw in 1977.
I saw this article on Yahoo News and thought everyone might want to see it regarding both Rovers on Mars.
Martian dust storm affecting twin rovers:
http://news.yahoo.com/s/ap/20070705/ap_on_sc/mars_rovers;_ylt=AkehfcA59RNkZbvYqwxIae_737YB
Hope this doesn't get any worse... don't want to see pics like this coming down...
It would be awesome if the pictures can show something visually dramatic like that. Unfortunately, the pictures appear to show the the landscape getting slowly murkier and murkier. An animated movie would be awesome.
It's probably not too bad if any pictures can still come down. It's bad if no pictures can come down.
I know there's no way we'd ever get pics like that, I was just imaginin' ...
Can the rover be shut down until the storm passes? Or at least put in sleep mode?
Yes, but the heaters need to be on to keep the electronics in safe condition. Nomatter what, Opportunity needs a certain level of power to survive. The latest news suggests that those power levels are uncomfortably close to that lower limit even with sleep mode.
This is a very unfortunate turn of events. But if opportunity survives intact, then this storm and its aftermath is an incredible new science opportunity for the rover. Let's just hope that the dust storm does Not get any worse than it has over the 4th of July.
If you believe in the Gia hypothesis, then maybe Mars was just celebrating with it own brand of fireworks! ;-) ...the kind that some western states had to ban because of the drought.
What is the impact of the storm on dust deposition rates? Is the activity mostly too high in the atmosphere to blow heaps of dust onto the solar arrays?
TTT
Strangely, if I get this right - regional dust storms are quite good because they cause high wind speeds ( note the cleaning that Opportunity got just over a week ago ) - BUT I would imagine that there comes a point when the dust loading, whatever the wind speed, must cause increased deposition.
Doug
It must all fall down when the wind stops. If it causes almost complete obscuration when it's airborne then I fear it will do the same when it settles, unfortunately.
What happened after the, admitedly much more modest regional storm, that Opportunity had in the 600-ish range - the one that made it sleep in late one morning?
Doug
Are there any pictures of the dust storm anywhere? This isn't looking good.
Would not the air be warmer if the airborne dust is consuming the solar light? It's summer in the southern hemisphere, and Mars should be close to its perihelion, so maybe the power requirements for the heater are not so high as in the middle on the winter?
That's true - I remember the depths of Spirits winter, and they mentioned that they got away with less than the 240whrs they thought they needed, because the vehicle ended up staying warmer than they expected.
Doug
it is my oppinion that if Oppy survives this we should take to Ithaca...in shoulders!
Is the MRO's Mars Climate Sounder able to return observations that are helpful in understanding the current dust storms? Are the observations useful for rover operations or only for long-term assessments of the atmosphere?
TTT
Here's another nice site for amateur images of Mars, and other Mars news:
http://elvis.rowan.edu/marswatch/images.php
John.
Dr. Lemmon has an update on his http://www.lpl.arizona.edu/~lemmon/mer_dd.html, with some specific tau figures:
Just got some feedback that Sol 1225 Tau is 4.125.
Oppy is at 255Whr.
Pray!
The dust storm has delayed Oppy from entering Victoria Crater for now:
http://www.jpl.nasa.gov/news/features.cfm?feature=1411
What with the stuck shoulder joint heater, 255 is a lot worse for Opportunity than for Spirit
Doug
Dust storm.... high tau...... high winds.....
Knowledge always comes with a price......
Yes, hang in there little rovers......
Craig
There is an interesting article about dust storms on the hubble-site http://hubblesite.org/newscenter/archive/releases/2001/31/text/ - that foretells a possible second following storm. (Hope not!)
Here's the relevant excerpt:
After three months, the storm is beginning to wane. The planet's shrouded surface has cooled, and this allowed the winds to die down and the fine dust to begin settling. However, Mars is approaching the closest point of its orbit to the Sun. Once the atmosphere begins to clear, the return of unfiltered solar radiation may trigger additional high winds and kick up the dust all over again. This one-two punch has been seen in previous Mars storms for centuries.
The article is old - but could multiple storms be caused, or have been caused in this fashion with this episode?
Multiple major storms do happen in some years - the Vikings saw two in 1977 for example.
At least she was still taking pictures on sol 1225, and the calibration target looks clean. It's now morning on sol 1226. Let's keep our fingers crossed...
http://www.flickr.com/photos/marscat/737827497/
http://www.flickr.com/photos/marscat/737827331/
Speaking of Hubble, it will look at Mars near the end of this month to help with MARCI's calibration woes, but in the process, it may catch the aftermath of this.
colorized Spirit sol 1244 ( July 4, 2007 ) L0 1x2:
http://www.flickr.com/photos/hortonheardawho/738900848/
Just a guess.
I'm actually a little more worried about Spirit than I am about Oppy. This dust is all still entrained in the atmosphere, it hasn't really started to fall out yet. I don't know why, but I have this gut feeling that Meridiani may collect less dust from this storm than Gusev eventually will. Maybe because there is less overall dust accumulation on the ground at Meridiani than there is at Gusev; it just feels like Meridiani doesn't collect dust as effectively as Gusev does. (Maybe Gusev's crater rim causes a large-scale swirl in the winds that tends to make dust collect within, while the lack of any such circulation patterns at Meridiani keeps it from getting dumped on nearly as much.)
I guess I'm thinking that the dust ought to have specific patterns of fallout, based on when in the year the storms occur and what the wind patterns are like at the time. It also may have something to do with your distance from where the storms start and how they grow. It just feels like, since Oppy was closer to this storm as it formed, it may actually get away with having less of the dust dumped on it than other places on the planet -- perhaps even halfway across the globe.
Also, rather obviously, the polar caps display a process in which dust is often sandwiched between layers of dry ice. It may well be that a majority of the dust pulled up during these major storms ends up being deposited at the fall/winter pole, to which the air is flowing and where the air is precipitating out and plating itself onto the ground. That would tend to make sense from a global circulation pattern perspective.
-the other Doug
Some new information in this National Geographic http://news.nationalgeographic.com/news/2007/07/070706-rovers-dust.html.
Jacob Matijevic is confident of rover survival.
Jake seems confident;
best rover news I've heard in a couple of days!
A handful of sol 1226 images are online. Just solar-filter images so far.
Sol 1226...look how clean the rover looks!
http://qt.exploratorium.edu/mars/opportunity/navcam/2007-07-06/1N236754570EFF85R9P1962R0M1.JPG
She looked very clean, but that image should be from sol 1223. I suspect she is still pretty clean, despite the dust storm.
It's nice to hear that somewhat positive news from national geographic. I can't help but wonder if this would have been more of a survivability issue for the rovers if they hadn't been cleaned by the earlier winds. I also can't help but wonder if such early, cleaning winds might be expected prior to a dust storm.
www.spaceweather.com reports the storm has intensified and grown.
Strong winds with the storm mean that Opportunity's going to be VERY clean as long as we don't catch a big chunk of dust when...er...the dust settles, as it were
Doug
As a reminder, here are the fully calibrated comparison pics showing the minimum of light level encountered by Viking Lander 1 on sol 324 (1977).
Tau was between 5 and 6 depending your reading sources...
Enjoy ! (if I may say...)
Hey, welcome back vikingmars! Missed your gorgeous pics!
Just for my own interest, not claiming 1000% accuracy or anything, but there's a LOT less detail visible on them that hills...
( left: June 13th, right: yestersol. )
how do we know how high the winds are at the surface?
Well - from the rovers we don't really. For dust to be leaving the rover it has to be 'higher' than normal. Orbital imagery can track dust, clouds etc and gauge wind speeds that way.
Just a bit of fun from the values on Mark's page. Looks like we might be seing the turn in the trend- but as you can see, Meridiani already fooled us once in that regard.
Doug
OK - doing a total inline quote is one thing - doing it with your own post is madness!
Pointless quote removed! - Doug
And shine a light on your petals!!!!!!!
Craig
Yes, whatever goes up must come down, but thanks to the winds it also travels sideways. I guess it's kind of a crap shoot. As the forces blowing dust around this planet run out of energy, let us hope that most of the entrained dust falls somewhere else. Everyone, cross your fingers.
Let´s hope for this descending trend in the tau values.
Meanwhile, Opportunity´s imaging operations are limited to tau measurements only since sol 1226. Same is expected/planned for tosol (1229) and tomorrow.
The early trend is in the hoped-for direction, but Dr. Lemmon's page still has no new tau values as I go to sleep tonight.
Ignore the last Opportunity point - that's my guess, not an actual value.
I THINK...(well, guess) that we're closer to the 400 whr level rather than the 255 whr level now.
Doug
Out of curiosity, to reach Tau levels as we saw here (e.g. 4.0) would it typically take a storm to throw it up?
As such, would there be globally increased wind levels? Or can the storm be localised and kick the dust up into the higher atmosphere, leaving regions further from the storm with normal winds (virtually none) but high Tau? I don't know how low atmospheric pressure affects all that.
While high Tau is bad for solar junkies like Oppy and Spirit, will these events have helped glean a better understanding of mass air movement on Mars? What will they be trying to learn from the past few weeks?
Sorry for all the questions, guess I'm just thinking out loud....
During Monday's Phoenix Mission press conference, Doug McCuistion, NASA's Mars Exploration Program manager, gave a brief but upbeat report on Opportunity's ability to survive the storm. I thought I also heard him say that Opportunity could function at a power level of about 100 watts. (It appeared later on that at least one reporter interpreted the 100 watts comment as referring to Phoenix, but I recall it as relating to the rovers).
That's a lot lower than the approximately 270-80 watt figure that's been discussed here as the rover's survival threshold. I assume that a good deal of the difference is represented by the fact that less power (no power?) ihttp://news.nationalgeographic.com/news/2007/07/070706-rovers-dust.html
Aside from heating, does anyone know what functions require power (and how much) for minimum survival? Does the rover draw no power at all during Deep Sleep?
TTT
Edit to fix typo.
To cut down power consumption, they would also need to reduce communication windows.
Emily has posted a http://www.planetary.org/blog/article/00001029/ on her blog, with a full transcript of McCuistion's comments.
Most intriguing was this, which I had forgotten: "We have the ability to charge the batteries below 100 Watts. We can do imaging even below 100 Watts. So we can select the instruments we want; we don't communicate with the orbiters as frequently."
Emily has also promised to try to obtain more information.
TTT
I've been looking for images of the magnets on the rover. I found a few; but I wish I could find a whole lot more.
These are the most recent images downloaded in order.
June 27th, 2007
http://qt.exploratorium.edu/mars/opportunity/micro_imager/2007-06-27/1M236222506EFF85R9P2976M2M1.JPG
July 1st, 2007
http://qt.exploratorium.edu/mars/opportunity/micro_imager/2007-07-01/1M236222650EFF85R9P2976M2M1.JPG
July 3rd, 2007
http://qt.exploratorium.edu/mars/opportunity/micro_imager/2007-07-03/1M236754439EFF85R9P2936M2M1.JPG
July 9th, 2007
http://qt.exploratorium.edu/mars/opportunity/micro_imager/2007-07-09/1M236754439EFF85R9P2936M2M1.JPG
As you can see, the wind is blowing some of the magnetic particles off of the magnets. I think that is an indicator of just how strong some of these winds must be.
The first two are both from Sol 1217 and the last two are the same picture, from sol 1223.
So there is no evidence for more than one gust.
Yup - raw images 101. The date something appears at the Exploratorium has little relation to when it was actually taken. The file name shows you when it was taken
1M236222506EFF85R9P2976M2M1
That's the time tag in red.
Doug
jaywee,
Helvick, the forum expert on Martian solar power, briefly discussed the effect of dust on surface temperature http://www.unmannedspaceflight.com/index.php?s=&showtopic=4375&view=findpost&p=94286 (post #20, responding to http://www.unmannedspaceflight.com/index.php?s=&showtopic=4375&view=findpost&p=94279).
Of course it would also be great to hear what the Mars weather scientists are learning and expect to learn about this storm from the instruments in orbit.
TTT
http://midnightmarsbrowser.blogspot.com/
Get it.
Be confused no more.
Doug
I just noticed this http://www.aviationweek.com/aw/generic/story.jsp?id=news/aw070907p2.xml&headline=Rover%20Ready%20for%20Dangerous%20Descent%20After%20Dust%20Storm&channel=space (Rover Ready for Dangerous Descent After Dust Storm) It seems to have a little new information about the dust storm and operations planned for inside the crater.
Hi guys, I went to the Mars meeting at Caltech today and planned to get some answers but had to leave because I wasn't feeling well. I did catch Ray Arvidson before I left and asked him about the 100-Watt number and he said that was an error. A woman with him said she thought the number was more like 280 or 290.
--Emily
Hi all
A few times without posting because I've broken my wifi pcmcia card (thanks to gravity who have made fallen my laptop ). The problem is now solve.
I learned that a dust storm hit our rovers.... And Olivier made us a little visit
So, a picture I've made showing the inversion phenomena through the sky during a dust storm :
http://astrosurf.com/merimages/Opportunity/Images_en_couleur/Temp%EAte-Sol1224.jpg
And here, a color panorama of Victoria crater during the storm :
http://astrosurf.com/merimages/Images_opportunity-2007.html#Sol1224
In expecting that the storm will not during a lot of time
It's a pleasure to read you at new
That 255 whr figure for Sol 1225 is bugging me (Sorry Astr0 - feel free to object right back )
I calculate that at a Tau of 4.1 on Sol 1225 for Opportunity she should have generated around 310Whr.
All of the other numbers that I've seen recently indicate that the insolation model I'm using underestimates the real values by 10% or so ( e.g. on sol 1221 @ Tau=3.3 the MER team have published a value of 402 Whr when I estimated about 360 Whr ). That would make me expect a real value of about 340 Whr if the Tau value of 4.1 is correct. Furthermore I really suspect that there was at least one small (5% or so) cleaning event sometime between Sol 1211 and 1220 which would put the number closer to 355Whr.
The most likely reason for this is that the diffuse Insolation model I'm using becomes increasingly unreliable as Tau rises past ~3 but it is also possible that the 255 Whr number isn't accurate. I'm also very surprised at Opportunity being able to function at all at that level, my understanding all along has been that 270-280Whr is extremely marginal for her given her stuck heater.
Very much looking forward to published numbers from the team.
Is it possible that the Tau reading is just a single point on a line, ie the Tau could be 4.6 now, but could be lower or higher before and after that reading. Tau comes from looking at the sun, right? So power produced could be slightly off from what you expect because the dust isn't consistent either across the sky, or from morning to evening.
high dust opacity drops daytime temperatures, but raises nighttime temperatures.
Local dust storms, if strong, show strongly convecting or at least dynamically churning clouds, often with some mixed-in condensation clouds, as seen from orbit. They can probably be quite opaque, but then the dust spreads out and disperses, like the storm that happened shortly before Beagle and MER's arrived.
Globe-encercling storms have been observed from orbit in development phase 3 times (2 viking orbiter storms and the 2001 storm), and once in the decay phase (the greatest of all, the 1971 global storm: Mariner 9.) Storm heating probably has a massive "ripple" effect on the adjacent atmosphere, as well as strongly boosting global atmospheric thermally-driven tidal oscillations, and can probably cause unusually strong winds even in non-storm-dust affected areas before the dust arrives. Areas near an active storm may plausibly have such strong induced winds that there is strong local dust scouring and lifting, causing a propagation of the main storm, starting solar heating of the newly raised dust in a sort of chain-reaction effect.
We just don't really understand the meteorology of storms and their growth. Vikings got some good photography at intervals, as well as infrared thermal mapper data. The 2001 storm was before Odyssey's arrival, I think but had good coverage by MGS's wide angle cameras and the thermal infrared spectrometer. With the wide angle cam on recon orbiter and the climate sounder, we're getting our first meteorology instrument look at a big storm :-) I hope to hell the've switched the instrument back into scanning mode for the storm.
Thanks for the input folks.
The MER team's Tau values into account the solar zenith angle and the resulting increase in air mass as do my calculations for beam insolation. You can see this in the published Tau charts - the air mass numbers and DN's vary as they should with the changes in the local true solar time of the Pancam shots the readings are based on and the resulting Tau values are pretty consistent throughout each sol (on the occassions that multiple readings are taken)
However even though they are consistent there is definitely a daily cycle - Tau (generally) increases slightly over the course of a normal sol and then clears up slightly again overnight. Whether this cycle is more or less pronounced during a storm I can't say but for the vast majority of the year the variation is <0.1 over the course of each sol. To explain the variation I'm puzzled by we would need a variation of about 2.0 for about half the sol.
It is probable that part of the explanation is that very short time scale events (passing higher density dust flurries for example) are causing significant variations in Tau during the day.
For fun, a question that I can probably dig for an answer for if there is not a quick one available here.....
Question: Is there engineering data available from the rovers (in the PDS I would presume) which reports the output from the solar arrays? If so, what is the temporal resolution (and averaging period if any) of the data?
It would be fascinating data if available in decent resolution.
-- Pertinax
I was wondering if we have, here on Earth, the equivalent of Marsian's dust storms?
For exemple, dusts coming from deserts that goes very high in our atmosphere where the pressure could be comparable to what it is on Mars?
Saharan dust landing on cars in the UK isn't uncommon - I remeber two distinct occurances of that in the past decade or so.
Meanwhile - updated to 1230/1250 actual figures
Massive kudos to Mark for putting these on line so quickly.
The Sirocco:
Some nice pics here of the dust blowing from the Sahara up towards Europe.
http://en.wikipedia.org/wiki/Sirocco
Infact -thinking about it - I remember finding comedy in the fact that a Sirocco was dumping sand on my mums VW Sirocco.
Doug
A similar phenomenon we have here is "muddy rain"; it isn't really muddy, of course, but it is rich enough in dust that was lofted into the atmosphere in arid West Texas and deposited here to leave a significant film on one's car.
'helvick' said that figure is "bugging me".
Hi Helvick,
That number came straight from someone on the MER team.
I'm sure that there's room for error though.
Astro0
The latest navcam shows several changes in the tracks - the wind's been a-howlin' at Meridiani. And the shadows are much stronger now! (These views are less than half an hour apart local time.)
http://marsrovers.jpl.nasa.gov/gallery/all/1/n/1224/1N236844860EFF85R9P1963R0M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/1/n/1231/1N237464520EFF85R9P1963R0M1.JPG
Thanks for the confirmation Astr0. I'm going to have to hope that this means that Tau was varying fairly dramatically that day. Otherwise I might have to accept I've been wrong. Oh The Shame!
According to this report on space.com the dust storm is still spreading.
http://www.space.com/scienceastronomy/070711_mars_dust.html
and
http://themis.asu.edu/dustmaps/
The enormous dust storm raging across Mars' southern half has begun to creep into the northern hemisphere as well, new satellite images reveal.
"This storm isn't as big or severe as the one in 2001," Bandfield said. "THEMIS and other orbiters can still see the surface, despite the continuing dust activity."
It's uncertain how long the current storm will last, but it probably won't disappear as quickly as it began. "Mars will remain dusty for at least a couple more months," Bandfield predicts.
Sounds like the rovers will remain power-starved for a Long time.
Good eyes fredk. I'm going to make an animation to show this more evident
The Themis link is very good : hop! direct favourite
Edit : gif is finish.
It occurs to me after comments in the Spirit thread that even though the local times are very similar in the two navcams I posted above, the tau has dropped from around 4 to around 3 so the lighting is less diffuse now. That should account for some of the changes visible in the tracks, but not all.
From http://www.lpl.arizona.edu/~lemmon/mer_dd.html Oppy is stable at tau = 2.9 as of sol 1231, but Spirit has climbed in the past few sols to tau = 2.8 on sol 1252, which is the highest Spirit has ever been.
I get the sense this could linger for some time. http://en.wikipedia.org/wiki/It_ain't_over_'til_the_fat_lady_sings
I think you are correct Fred. This storm is not over yet. It could last a few more weeks. These peaks keep rolling into new peaks for other areas of Mars. We don't how bad this will get. It appears to becoming a global storm. Yet as far as we know, it could start to settle down tomorrow.
I'm glad that the tau at Meridiani appears to be stable; but who knows what will happen next?
What Viking and Mariner 9 saw was that storm activity keeps popping up and regenerating as long as there are relatively clearer parts of the atmosphere.
Once circulation and recirculation of storm-dust has pretty much uniformly filled the atmosphere with some relatively uniform few tau of dust, temperature differences drop below levels needed to churn up more dust. The storm then transitions to a decay phase, with an atmospheric dust half life of something like a couple weeks. Maybe that's equivalent to one tau's drop per two weeks..
Viking had two dust storms in one year -- most unusual -- the second one started just after the decay of the first storm got dust levels down to maybe about tau=1.. the levels present before the first storm really started.
As I recall, the first storm was pre-perihelion.. late spring.. the second was in summer.
talking of popping up again...
I've added a few bits - can you tell I was bored on the train yesterday
Hi Doug
These graphs have been very helpful to get an idea of whats going on.
Thanks for finding Marks data so quickly and putting it on the site, nice new touches too but perhaps there should be more orange (dust) on the top half of the graph to match the Tau going up.
Roy
Well, according to Mark Lemmon's site tau is now 3.3 for Spirit. Same as Oppy. Maybe it will stabilize around this value then.
Everybody says Martian dust storms begin in the summer. But what time of year IS it anyway? The official MER-site and the MMB both have very nice martian clocks, but no calendar!
Is it 'June', 'July' or 'August' now? And is there a comparison somewhere on the net with the 1971 and 2001 storms? In which 'months' did those storms start and decay?
The southern summer solstice was last week.
For a Mars calendar/clock, I like Mars24:
http://www.giss.nasa.gov/tools/mars24/
--Greg
And here's a table showing some past and future Mars seasonal dates. I have always intended to add some past ones going back to Mariner days, but never got around to sitting down with Mars24 and plugging dates in to find all the solstices and equinoxes.
http://planetary.org/explore/topics/mars/calendar.html
The Mars dust storm season begins just after perihelion at around Ls = 260°, wich is 10° (that is, 1/36 of a year or 1/3 "month", whatever that means for Mars) before the summer solstice.
--Emily
Look at those drastic differences in the tracks after the new drive!
http://qt.exploratorium.edu/mars/opportunity/pancam/2007-07-13/1P237557300EFF85RZP2571L2M1.JPG
That's amazing. Does anyone know which days those tracks are from? I know the clear ones were just made.
Actually....from mark lemmon's site:
Sol 1233B: Opacity B1233 was 3.8 but it got above 4 during the sol.
Continues to rise for both Oppy and Spirit. Unfortunately.
D'oh. Okay, I guess it has spiked back up. How unfortunate.
Yeah, mhoward, I could have said "some updated old numbers".
Speaking of http://www.lpl.arizona.edu/~lemmon/mer_dd.html he also writes:
Yeah, I saw those frames come down today and wondered, "are they doing DD movies at Meridiani?" I suspect all of the frames are not down, but some looked to be fast, and others were many seconds apart. We at least seem to have parts of two movies so far.
I thought I noticed some subtle, local brightness variations in the sky among the available raw navcams. Maybe some of our "above the horizon" image magicians can find evidence of dust being lifted from the ground. That's what I think was meant by lifting.
The storm is certainly not subsiding yet. Meridiani and Gusev are experiencing new peaks. Searching for some good news, it sounds as if the rovers have plans for tau values around 5,
New record for Opportunity on B1234 of 4.2. Much kudos to Mark for keeping the figures updated despite being involved in a Phoenix ORT.
Doug
Oh my...not good. I searched in vain for the latest amateur Mars obs of this storm...anybody have any updates? This data suggests regional enrichment.
Damian Peach has put a few up at the BAA website ( www.britastro.org )
Doug
I also found this site:
http://elvis.rowan.edu/marswatch/news.php
Click on images on the left.
Some new info on the HiRise blog. From July 11th:
http://hirise.lpl.arizona.edu/HiBlog/?p=92#more-92
Some HiLights:
At this point, the storm is considered a "hemispherical event," meaning it's mainly affecting "only" half of the planet (the southern hemisphere, in this case). We have our fingers crossed that this will not expand and become a global event like the 2001 dust storm.
The CRISM instrument can measure the composition of the dust, for example, so we've helped them acquire extra images by canceling a number of our own images that would have been obstructed by the dust anyway.
While we wait to see what the dust does, our Targeting Specialists are scrambling to cancel observations and figure out where to take a chance and try imaging.
From New Scientist: http://space.newscientist.com/article/dn12276-martian-dust-storm-continues-to-affect-rovers.html
I'm still a bit worried. As I said before it all has to fall down and it won't be any less opaque when it does. If it's 'hemispheric' as opposed to regional then there is no escape from the debris. We will need a fortuitous late gust at the end of the storm to do the cleaning.
Hopefully it will all fall in the northern hemisphere
The distant horizon is fading from view. Compare this sequence from sols 1225, 1233, and 1235, taken near the same local time:
http://marsrovers.jpl.nasa.gov/gallery/all/1/p/1225/1P236931207EFF85R9P2629L6M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/1/p/1233/1P237639549EFF85W0P2688L6M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/1/p/1235/1P237817092EFF85W0P2689L6M1.JPG
Still no word on tau for 1235, but tau was a bit higher on 1225 than 1233. Yet the horizon is hazier on 1233. This seems to suggest that the atmosphere was dustier at low altitudes on 1233, but a bit clearer overall. Is this due to dust settling? Or to new dust being kicked up from the surface?
Things aren't pretty right now, my sources tell me that tau is about 5 and increasing.
Let's all hope Oppy survives this...
More than 5! NIGHTMARE.
I'll have to change the scale of the Y axis on my graph!!!
Ouch... What's the bare minimum of whrs Opportunity needs to survive and can it survive with less than that for a short period of time? 150 whrs? How about 100?
Fuzy horizon, dark ground, too red skies,
I request for clearer days.
Damn, the winds must be really picking up.
This is bad...very, very bad. The worst part about it is the wait for information.
This is like having a family member in the hospital and not knowing whether they are going to make it.
http://www.unmannedspaceflight.com/index.php?showtopic=821
Funny then. Not funny in THIS situation IMHO.
These could be the last pictures Opportunity transmits:
http://qt.exploratorium.edu/mars/opportunity/navcam/2007-07-17/1N237728274ESF85W0P1569L0M1.JPG
I have a fair ammount of confidence that even with a couple of weeks of <200whrs essentially out of touch all together - the vehicle would be recoverable once the tau gets back to <3. It's summer, it's warmer at night, perhaps the MiniTES lens will go (but it hasn't with some very cold nights so far) - but I'm quietly confident.
Doug
Speaking of lenses, I wonder what all this particle movement is doing to the hazcams. It's not uncommon in the US desert Southwest regions for autmobile windshields to become buffed and pitted in sandstorms. The MI has a cover, and the pancam can be pointed downward but those hazcams just have to sit and take it.
Spirit's FHAZ's are filthy right now, that much is obvious.
Doug
Tau 5! very scary.
I remember Mariner 9....... was just out of High School and wandering the hippie havens of the University of Akron.
That 1971 dust storm actually helped dispel the notion that Mars was just a larger version of cratered Luna but with a wisp of atmosphere. I will never forget seeing the "spots" materialize out of the settling dust...
which turned out to be the summits of the Tharsis volcanoes..... the dust storm of 71 helped to highlight those features. And a revolution in our understanding of Mars.
Now, 36 years later, we are seeing the effects of one of these storms from the ground. I cannot help but find this fascinating as well as scary.
But....
Hang in there, Little Rovers....
Craig
From Lemmon's site, Oppy's at 5.0-5.2 (sol 1236), "estimate based on array energy due to a no-activity plan, and last data for a couple sols".
Hang in there, indeed.
Also from Lemmon's site
I'd be lying if I said I am not concerned, but I am not terribly worried at this point, either. Oppy has felt she had enough power to take some images through sol 1236, even though the images have decreased in number. Furthermore, she has transmitted tens of images, including those "dust lifting" movies taken on sols 1233-4 as recently as today (sol 1237), two sols into tau5 conditions.
They have apparently suspended imaging as of sol 1237 and are not planning activities for a while, I am guessing as a precautionary measure.
One thing that we all can feel happy about is that both rovers look to be as clean as whistles, and so are able to absorb as many photons as are able to penetrate the gloom. Being a die hard optimist, I was looking for other good news, and this is the best I could come up with. There has been a bit of a correlation between tau, as recently measured by Spirit, and that measured by Opportunity. Just look at Doug's graph. According to Dr. Lemmon's site Spirit has seen a slight decrease from it's recent peak tau, from 3.8 to 3.6. That was tosol. We might not, but then again we just might, see dust levels on this side of the planet do something similar. Let us pray that it doesn't get much worse.
Just as an example of how the current low power situation affects the rover activities, sol 1235 was initially planned to be a driving sol but only a few imaging sequences were executed, driving was cancelled. Imaging started around 10:54 local time and finished at 11:35; just 40 minutes of activities.
If we compare that with, let's say, sol 1203, the difference is significant. That sol imaging activities started at 09:41am, followed by a 60m drive lasting from 12:35 to 14:04, and finished at 16:31; that means a rover alive and kicking during almost seven hours!
Hang in there girls.
Yikes indeed
And I think it would look even worse with the figures for the previous month in, a nice flat line at first and then it would sky rocket.
It would not be a good idea to put a trend line on that curve as it would be too depressing.
Roy
Think positive, we have a clean rover and summer temperatures. Things could be much worse with dirty solar panels and during winter times.
I'm worried about the fact that the last 5.2 value is based on array energy only. Look at these images from Horton:
http://www.flickr.com/photos/hortonheardawho/831774782/
I get the impression there's more dust on the deck on sol 1235. What if the power is dropping because there's more and more dust deposition?
From this image, I tend rather torward more dust coming along with the wind than from above. Anyway we will need "back side" wind after the clouds of dust are over, I think.
Rather such dust stroms on Mars than one from Earth http://tagesschau.sf.tv/sfvideo/view/173120/1 (click "Breitband (450 kbit/s)")
Here is the development of the
Duststorm seen through the eye of Spirit.
Views taken with the L5 Pancam between
Sol 1216 and Sol 1255
jvandriel
Wow, that's pretty scary.
Saw it mentioned that summer temps might be kind to the rovers, but what is the primary part that, if failed, would stop a rover waking up in the morning.
Is it the WEB cooling down too much?
5.2-5.5 guestimated from array power on Marks latest update.
Doug
Bad news.
Well - good news in so far as the vehicle is healthy enough to tell us the solar array output from which the figure has been derived.
Doug
And, for those of you not reloading Lemmon's page every five minutes, also this:
Pardon my ignorance, but if they do a deep sleep during the day to save power - would the batteries still charge? Or is that an automatic hardwired function?
Just wondering if they would even want to do that to conserver power to ride out the worst...
It would be ironic and cruel beyond words if Oppy succumbed to this dust storm after all she's survived to get here. What an adventure she's had so far... Surviving technical difficulties and deadlines on Earth before launch, then surviving the fiery plunge thru Mars' atmosphere, the boing-boing of landing and the "hole in one" bounce into Eagle Crater... countless long treks across the Meridiani desert... getting stuck in Purgatory Dune... the loooooong drive south the Victoria... and now, just when she was days away from entering the crater, and fulfilling what many see as her destiny - to explore the interior of the huge martian crater - the Great Ghoul of Mars, that has claimed so many other probes, finally turns its gaze on little Oppy and stops her in her tracks...
Trying to think positive
I'm wondering if, once the Storm will have receded, it'll be worth trying to re-image all the others landers (V1, V2, MPF) to see if we can see any clean-ups as we see on Spirit & Oppy. I'm not sure the differences in albedo will show up but it could be an idea to submit to MRO's team. Any thoughts ?
Thanks Del Palmer, that's what I was afraid of...
I become te be more and more anxious about the rovers and especially for Oppy.
I have the very bad sensation that the storm will not dicrease so quickly and will during a few month...
I have lots of feelings for the rovers and this could be a shock to broke definitly contact with them
I want to say in french : tempęte, je commence ŕ en avoir ma claque, tu dégages de lŕ!!
Well, we definitely don't want a dead battery while in deep sleep. If that happens, then I'm afraid it would be R.I.P. for the rover.
Actually, after thinking and reading more about this, I'm not sure it's actually possible to deep sleep during the day (unless day is like night, not impossible at the moment!) as deep sleep works by disconnecting the BCB and ends when the BCB is naturally repowered by the solar arrays at dawn (when ~0.2 Amps is generated), ending deep sleep whether you want it to or not.
James
There are so many questions I could ask here - eg, if the batteries are receiving little or no charge from the arrays, but are fully charged to begin with, how long will they retain their charge? I'm also curious whether they've had any sort of "action plan" in place for this kind of scenario. More than anything, I'd like to hear the level of confidence that the folks in control are expressing at this time. The last we heard from Squyres a few days ago was pretty confident.
BTW, welcome back James!
But - iirc - that heater only comes on if it's cold.
I was thinking that actually the situation might arise when it's better to leave the battery cut off because even at noon, the array output wouldn't be high enough to power the heater - BUT - citing Encyclopedia Roveranica (Roving Mars ) -
"It kicked in half an hour before midnight Mars time, and it didn't go away until about 1000 the next morning. And whatever was responsible, it sucked more than 170 watt-hours of energy out of the batteries overnight"
Given that it's summer, and warm because of the dust - the arm heater might not kick in at all.
I don't know the specifics of the PCB, but is it intelligent enough to be preprogrammed for an expected wake up array voltage of X volts (when X is a lower number right now ) - which could be estimated to be 11am - then the master sequence for the day is sleep all day, wake up for the earliest Odyssey pass at which point you both uplink for the next day and downlink for that day, and then enter deep sleep till 19 hours later.
Doug
I'm doing some research to write about the storm and just thought I'd share some now-comical quotes from http://www.planetary.org/news/2007/0131_Mars_Exploration_Rovers_Update_Spirit.html regarding tau values measured by Spirit:
Latest update for Spirit: tau at 4.0
To add a little bit more to our stress : is there one of the two rovers in restricted sols at this time ?
I was searching for more information about the current status of the rovers, but found this video instead--Unfinished Business. Please excuse the distraction at the beginning before the video starts.
http://www.space.com/php/video/player.php?video_id=060707Rovers_end
I certainly hope this global storm does not signify the end. At least, I'm not willing to give up hope, even if communications stop. It's possible communications could still be reestablished again when the dust settles.
Latest update on the tau values by Mark Lemmon for Opportunity is 4.6-4.8 for sol 1238.
We are back below 5.0. Uff!
I never thorght i'd be glad to see a Tau of 4.6-4.8!
That should give about 200Whr if my maths is right. That is probably just about enough, right?
James
Keeping it up to date
Even with 200 Whrs - all I'd want to do is charge the battery. Figure out the times of day when solar-array wattage > non-deep-sleeping rover wattage requirements and just power up for those times and then shut down again. Be 'on' when the potential is for power-positive operations, be 'off' the rest of the time. Because if this storm has taught us anything it's that it can get worse again faster than it gets better.
Doug
There are still down links every day. It's just not in time to do planning.
Actually - they've started culling them. According to Mark, they tried an uplink on 1237 to tell the rover to NOT to that afternoon's Odyssey pass- but the uplink didn't go through
(my best guess - an atmosphere rammed full of ferric dust does things to radio waves)
Doug
Back of envelope maths...
A full battery is 600 Whrs.
Basic spirit ops during winter were 240 Whrs
Opportunity currently 150-200 Whrs ( let's say average of 175 )
Battery Out In End
600 240 175 535
535 240 175 470
470 240 175 405
405 240 175 340
340 240 175 275
275 240 175 210
210 240 175 145
145 240 175 80
80 240 175 15
15 240 175 -50
etc etc
Doug
A few questions :
Do we know if there's a day/night effect on the storm? If yes, can this explain tau ups & downs?
Did we see this with Viking?
Are storms able to increase Tau at Phoenix landing latitude ?
Spirit atmospheric observations following upadated with the Sol 1254, where we "see" Grissom Hill faintly :
http://astrosurf.com/merimages/Images_de_spirit-2007.html#atmopacite
And in addition, an animation showing Grissom Hill "immersion" through the thickness of the dust storm :
A full NEW battery is 600 W-hrs. These batteries are ~5 years old and have gone through >1200 discharge cycles. We're probably looking at more like 400 W-hrs max capacity now given that the cells show a ~30% charge capacity loss after 1000 cycles. That cuts a few days off the run-down-to-dead calculations. http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/38847/1/04-2590.pdf
To be fair - it's more like 10.2 Ahrs down to about 8 Ahrs - so from 600 Whrs to 470 Whrs at the very worst - but given that it's not had 1000+ FULL cycles - but partial cycles, and in good power states, probably less than 1/3rd cycle per sol - I would argue for >500Whrs of battery capacity.
Doug
But the question is not how much charge the batteries can hold but how much they actually have right now. I doubt the batteries are fully charged at the moment!
Also I was under the impression that Oppy could get away with quite a bit thess than 240Whr during these warm summer nights?
So all in all I don't think we can make any guesses about how long a rover can hold out under these conditions, not to mention how quickly these conditions change. We just need to hope, each sol they survive is one sol closer to the end of the storm...
James
Would moving Oppy to a more advantageous tilt and direction to the sun help at all in this situation? I know it worked well for Spirit last winter but that was not under these kinds of elevated dust levels. I'm thinking this lilypadding technique might give Oppy just a few more watts and it could be just enough to get her though the storm. Any thoughts on this idea?
MARCI images of the storm, including many over Opportunity:
http://www.msss.com/msss_images/2007/07/19/
EDIT: Arg. I was going to make an animation of the nine-frame image at the bottom but their little white circle showing Opportunity isn't quite steady on the map -- it's going to take a little doctoring to make it look right, which I don't have time for right now...maybe tomorrow...or maybe one of you will beat me to it
--Emily
None of the images in that sequence nor the circles are aligned properly.
Line up the circles and the background jumps. Line up the background and the circle jumps.
However, if you just animate them anyway, you get the idea of just how bad this storm has been.
A very big dust cloud sweeps around Oppy's location from left to right, then a big cloud comes from the south and seems to land of top before everything is obscured from view.
Astro0
EDIT: I've updated the image to blend out the missing data. Not perfect but it gives you an idea of what's happening.
The baby gave me a little more time to work after all, so here's my version. I found that only one of the circles was seriously badly aligned, so I fudged that one and aligned all the images on craters as long as I could see them (none visible in the last image!) I also replaced the black gores with a slightly less distracting color.
Wow, Astro0! I can't believe what I am seeing.
"...farthest hills are now almost completely invisible. This is under tau = 4.0 skies..."
Though the analysis of data will be more complicated than for sun images and for skylight data, the view of the hills gives an independent measure of dust opacity along a NEAR SURFACE line of sight, instead of integrated through the vertical height of the atmosphere. They are not necessarily the same.
Here's another stretched version of the storm to show up more of the lower cloud detail.
Astro0
What's with the wave-like effects that appear to correspond to MARCI's imaging strips and propagate to the east? I presume those are just imaging artifacts though they do look a bit like surface illumination effects?
Remember - this isn't a snapshot of the whole planet at one time - it's slices of planet at 3pm local - and thus you get lighting effects from one side of each stripe to the other.
Doug
I'm aware of the slices, but I forgot to take into account the wide FOV the instrument has that encompasses a range of local times, not just 3 PM. Shame, the "waves" distract from the dust clouds visible in the animations Astr0 and Emily posted and almost give a feeling of wave nature to the storm. In case of the dust storm there's probably an additional factor of optical depth of the atmosphere when looking way off nadir.
Gusev remained at Tau = 4.0 for 1259, for those few not watching Mark's page closely.
Pre-storm, I was wondering whether the decision to go with a nuclear-powered MSL was wise in the light of the MER's solar-electric longevity.
I have no doubts now.
Andy
Another advantage of a nuclear powered MSL is that it can work at night. Dust storms would not slow progress, and continuous night studies could be a very significant development. The MSL could operate basically 24/7 if need be.
I do think there could be some additional advantages if a combined approach could be developed for future missions. Also, maybe a soft brush could be included to manually sweep clean any solar arrays. I also hope that better wheels are developed. I would think something could fairly easily be developed to last a few thousand miles worth of surface travel. The problem might be staying within weight constraints.
That's why a combined approach might be useful. It might be too late to change the MSL design; but I don't think it will be the last rover. Also, 7 hours per Sol is an average. If the batteries are fully charged, then I believe that it could operate longer.
With a combined approach, then closer to continuous 24/7 could be achieved. However, the batteries might not last as long. So there are multiple trade offs.
I just think it would be a waste to completely throw away the advantages of solar power. The MER proves the application of the technology. I just want a brush so that we don't have to wait for the wind to blow.
Get rid of the brush, get rid of the arrays use an RTG and you've fine. And remember - there is another short-link in the chain. People. You can't have a rover that operates 24/7 - not least of all because you'd have to take floodlights with you - but also because you need downtime for the operations team to design the next sols sequence based on the results of the previous sequence. The downtime inbetween can be used a little like the rover's nights have been from time to time - APXS/Mossbauer integrations ( in the case of MSL - APXS integrations and the SAM suite )
You want to add arrays, a big arm with a brush ( which is more mass, more volume, more money )
That RTG is going to be producing X Watts, every hour of every sol, and that figure is more than is required to operate the vehicle. There isn't any sense in adding a further power source when you could spend the mass, volume and money elsewhere (like, a slightly larger RTG for instance). The very point of the RTG is that it gives a perfectly predictable, reliable power source for as long as you need it (over a primary mission of a martian year) - it's eliminates every down-side of the solar arrays in one - excuse the pun - sweep.
Doug
I always wondered why they couldn't emulate a good strong gust of wind by drawing in some Martian "air" and using a method of blowing off the dust.
Locate a nozzle in the centre of the array in such a way that as it spins as it blows and you could cover a large percentage of the array. Likely only needs to be pretty small and lightweight too.
You don't need floodlights. You just use infrared sensors. There is a whole host of instruments that you don't need lights for. It all depends upon what kind of science you want the rovers to do. You are correct that only certain things can be done during the day. Yet, valuable measurements could easily be done at night with the right instrument package.
The trade off because of human limitations is a valid point. Yet, team shift management can solve a lot of those problems. The real problem with approaching 24/7 is a commitment of time and money. It could be done and, in my opinion, would be worth it. But getting funding for such a program would be a problem.
NASA Mars Rovers Braving Severe Dust Storms:
http://www.jpl.nasa.gov/news/news.cfm?release=2007-080
On Tuesday, July 17, the output from Opportunity's solar panels dropped to 148 watt hours, the lowest point for either rover. On Wednesday, Opportunity's solar-panel output dropped even lower, to 128 watt hours.
Engineers calculate that skipping communications sessions should lower daily energy use to less than 130 watt hours.
A possible outcome of this storm is that one or both rovers could be damaged permanently or even disabled. Engineers will assess the capability of each rover after the storm clears.
Gulp... Only 128 Watt!
http://www.jpl.nasa.gov/news/news.cfm?release=2007-080.
"On Tuesday, July 17, the output from Opportunity's solar panels dropped to 148 watt hours, the lowest point for either rover. On Wednesday, Opportunity's solar-panel output dropped even lower, to 128 watt hours."
"To minimize further the amount of energy Opportunity is using, mission controllers sent commands on Wednesday, July 18, instructing the rover to refrain from communicating with Earth on Thursday and Friday. This is the first time either of the rovers has been told to skip communications for a day or more in order to conserve energy. Engineers calculate that skipping communications sessions should lower daily energy use to less than 130 watt hours"
Interesting quote from Richard Zurek:
http://www.jpl.nasa.gov/multimedia/audioclips/mer-20070720/
"If you're at the rover, for instance, sitting on the surface, and you're looking up at the sky, you're not going to see the sun's disk, even during the day because the cloud, the dust haze, is thick enough that the sunlight has been either absorbed or scattered."
How can this be? Spirit can still see the sun in those Tau images:
From Sol 1259 ( Tau 4 ):
Hum... That's explain the form of the Sun, a little stretched, by I longer exposure than a normal-tau day, due to Mars rotation during it?
"This is, I think, one of the most significant challenges we've faced over this entire mission," Squyres told http://www.space.com/news/070720_rover_dust.html today. "The nature of the risk is well understood, but the magnitude of the risk is not. We simply don't know what's going to happen next."
"Whatever we do, though, the problem is not going to get much better rapidly," he said. "I think that we have a good chance. If Mars really wants to kill these vehicles it can, but we have a lot of things working in our favor."
I saw videos of that electrostatic mechanism at the IAC'06 in Valencia - it was brilliant. Far FAR better than any mechanical system.
Doug
Meanwhile, even if kind of OT we get 2500 sols total today... and Spirit is very close to 100.000 pictures.
AND Spirit is only 20 sols away from beating Viking 2!
Back OT. From the space.com article:
If Mars really wants to kill these vehicles it can, but we have a lot of things working in our favor.
Question: what things?
THEMIS dust maps:
http://themis.asu.edu/dustmaps/
It'll last for years and years and years - like NH's or the Voyager ones.
Doug
The http://mars.jpl.nasa.gov/msl/technology/tech_power.html describes the RTG power system as "giv[ing] the mission an operating lifespan on Mars' surface of a full Martian year (687 Earth days) or more." (my emphasis) All the page is saying is that the power system will work for a lengthy nominal mission. It's not discussing how much longer than the nominal mission the RTG can operate.
The prose could be a little more clear, but I think that mission designers are understandably wary of making comments that could be interpreted as predictions of exceptionally long lifespans for the equipment. The fact that the RTG will keep working for decades isn't very important unless lots of other systems are still working as well.
TTT
Phew! Story posted. This was a complex one and done in a bit of a rush so I'd appreciate an email if anyone finds any errors.
http://www.planetary.org/news/2007/0720_The_2007_Martian_Dust_Storm_Crisis_for.html
--Emily
Thanks Emily, great article,
I'm still in awe looking at the http://www.planetary.org/image/Horizon_Survey_1205B_1235B.jpg image in there...
The MCS stuff is great as well - really good to see what could be an outreach-challenging instrument get good airtime via TPS.
Doug
There's a lot more where that came from -- I only got those graphs an hour before I posted, so there's much more in there than I had time to explain. More from MCS next week -- that's the instrument that's REALLY designed to stuyd what's going on with the storm.
--Emily
Emily,
Wonderful story; it's exactly what I was hoping for as a backgrounder on the storm.
Is MCL still unable to perform vertical profiles?
TTT
Emily,
As always, your article provides a clear and concise explanation of the situation. The dimming horizons graphic is outstanding.
Great work Emily, I always enjoy reading your articles!
Yeah, I agree with everyone else. That was really a well done summary, Emily. I'm still hopeful the storm is subsiding, and that the rovers will survive, but if not, we will still learn something...
Here is a set of 3 pics (calibrated and all that sort of things...) showing the fading of the local horizon at Gusev starting from sol 1122 to sol 1197 and finally ending at sol 1254.
Enjoy it (on Earth, NOT on Mars) !
Yes, I have the same question : where?
From http://www.reuters.com/article/scienceNews/idUSN2035182320070720 :
The rovers have electric heaters to prevent vital core electronics from getting too cold. One concern is that absence of sunlight could make the rovers drain their batteries.
That worst-case scenario is still weeks off at a minimum, Callas added. He said that because it was now Martian summer for the rovers, there was a chance temperatures would not fall low enough to ruin the electronics even if the rovers were starved of power.
Sounds optimistic.
Idle question -- please consider me off my rocker, but I'm curious if anyone's anticipating the storm to warm some areas enough for a "water release event" in various crater walls.
The phase diagram shows that the window for liquid water at these pressures is very small. It's quite likely that these conditions putting both the liquid AND solid phase out of the question for much of the day.
Doug
CBS News radio in Los Angeles picked up the story (pretty doom & gloom... ), had an interview with Robert Zubrin...was there a press conference today?
This may be viewing Mars through rose-colored glasses, but Our Intrepid Explorers have been though several tight situations and they've managed to survive. I'm sure they'll weather this dust event. And if not, it's ben a good ride...
--Bill
Anyone unfamiliar with Vikingmars's work - or wondering "how he does it" should check out his stunning book "Visions of Mars", which is truly a thing of beauty. If "Roving Mars" is The Book for engineering types, then Olivier's book is The Book for all us romantics and frustrated artists out here.
Been working on this for a while, hope some of you like it...
THE STORM
The Sun has almost gone now,
fading from my sight behind
a molasses-murky sky, and Earth’s
post-sunset sapphire spark
is just a distant memory.
I cannot move, and drooling over new Victorian vistas
must await until Sol’s golden glow
warms my frozen heart again for I am cold,
so cold, and feel ten thousand sols old
as I stand here, fearful that the dust I see
fouling the sky above me will fall suddenly,
smothering me, Mars murdering me
with her deadly pillow of particles
pushed down against my face –
But I am not dead yet, and although
I itch insanely, and would scratch myself
to wreckage if I had been built with hands
I shall stand here, sentinel-still, until
the sky begins to clear… or I hear
my stubborn heartbeat start to slow,
and then I’ll know my stay
on Meridiani’s rolling plains is at an end
and you, my faithful friends Out There,
must promise not to mourn for me,
but celebrate my life and all the wondrous sights
we saw together. Never think
of me with sadness, but be glad
we walked this world hand in hand,
cresting wind-carved dunes, swooning
at the sight of sunlight painting
Endurance’s epic walls,
falling to our knees in awe as
Victoria’s rippled floor opened up before us..!
But trust me, while a single warming spark
sputters on inside my shivering heart
I will prevail, and as the dust clouds sail
across my sky I shall just close my eyes
against the wind and bide my time,
for Barsoom gloomiest, darkest day
is still a thing of beauty… And if I am to die
here I will still have lived a life
far longer than was planned in this land
of rock and stone. Meridiani is my home,
and if Victoria is to be my lonely
tomb then there is no view I would rather see,
as I drift into my final, well-earned sleep.
© Stuart Atkinson 2007
As long as the rover is internally warm enough, then there shouldn't be any component failures - it doesn't really matter how hot it gets - as long as it's not too hot.
The challenge is this. Is combination of whatever energy they are using inside the WEB plus the 8w of RHU's (two on the rem, 6 on the bettery) enough to put enough heat into the WEB to keep the night min.temp. above whatever temperature would cause a failures?
Given that the use of deep sleep has been a regular thing - and that survival heaters were used only during the very coldest nights with Spirit - and that graph suggests 15-20 degrees warmer minimums - then I don't see it as a problem.
[quote name='MichaelT' date='Jul 22 2007, 10:06 AM' post='95554']
I had a search for some Viking data of the great dust storm in 1977 to find out what happened to temperatures then. .../... I do not know how representative such a temperature record is for a Martian dust storm, but, it shows that the daily average temperature does not increase. Rather, the diurnal temperature range is greatly reduced. he nightly minimum is higher, but, the daily maximum also much lower. That nights are warmer is certainly a good thing. What about the much lower daily maximum, though? Any ideas?
Michael
I confirm, Michael :
Here are your figures of temperatures (Celcius) during dust storms measured by VL1 and VL2 :
5:00 AM 2:00 PM
VL1 -83° -69°
VL2 -81° -71°
Yes : the rovers will suffer a lot !
Enjoy (if I may say..)
Stu... perfect words as always.
I've been working on a illustration for 'The Storm' and now you've created the words to accompany it.
Brilliant prose. I hope that other UMSF'ers appreciate it as well.
Cheers
Astro0
Don Parker's new shots really show how bad it has gotten.
http://img515.imageshack.us/my.php?image=bdd4bj4.jpg
Playing what-if: What if the batteries go to zero, but the temperature doesn't go low enough to damage the electronics. Would it be possible to restart the rovers when power is available? If power goes to zero one or more times, would that in itself be damaging to the batteries?
I don't think that's a damaging scenario - Li-Ion's don't have memory issues like some older technologies - but I think the tie in is that a little bit of battery activity is possibly required to keep them warm enough to avoid damage.
Doug
Is the next planned communications session sometime today?
http://trs-new.jpl.nasa.gov/dspace/handle/2014/39793
Very interesting stuff - well worth reading.
Doug
Thanks for the update Mark.
If the circuitry is such that it can charge even without an array wake up - will each sol be, technically, power positive?
Doug
Mark, thanks for a very informative answer!
Ahh - so actually - things are better than I thought they might be. Still a bit crap - but not quite as doom and gloom as I thought.
I'm going to plough through the JPL TRS search again and see if I can't understand and interpret this at a system level a little better - BUT - I think this may be the sort of flow of things as I understand them. I'm still not sure whever the cut-off of deep sleep is though.
Obviously ITAR has both hands firmly around the neck of any detailed info on this stuff - BUT - from here :
http://hobbiton.thisside.net/rovermanual/
specifically here
http://newport.eecs.uci.edu/impacct/d_research/d_presentation/JPL-PACC092600.ppt - very very out of date but I'm sure the figures are still roughly accurate
Suggests the 'battery charger board' ( I assume the battery controller board which you refer to) pulls 200mW - <5Whrs / sol.
Rovers are complicated.
Doug
Cautious optimism as reported in space.com (italics added)
http://www.space.com/scienceastronomy/070723_rovers_update.html
>Steve Squyres of Cornell University, the lead scientist for the Mars Exploration
>Rovers (MER) project, said that both Spirit and Opportunity are in
>"excellent shape" based on a radio transmission received this morning.
>
>"Both came through the weekend beautifully," Squyres said in a telephone interview.
>"They were both power positive over the weekend, meaning they were generating
>more power than they were consuming."
>
>The amount of sunlight penetrating the dust-choked martian atmosphere has
>increased slightly in recent days, and the batteries of both rovers are fully charged,
>said Michael Meyer, lead scientist for the Mars Explorations Program at NASA
>Headquarters in Washington, D.C.
***
>"At its worst, tau was a little over five [for Opportunity]," Meyers told SPACE.com. "
>It now has dropped down to a little less than four."
>
>The tau value for Spirit, hunkered down half a world away from its twin,
>has dropped slightly and is currently just less than four, Meyers added.
Of course the storm could get worse again, as the article mentions.
TTT
With a Tau of 5 and <1% of sunlight getting to the surface, how much worse could it get? What would it take to really knock down diffuse lighting worse then it has been and to a truly catastrophic level?
For solar reliant machines, these rovers really are marvels of modern engineering, coming out power positive after what was the worst of the storm to date. A credit to the people watching out for them.
Extraordinary. People have been asking me 'how long can they hibernate' - and under these sorts of conditions, it would seem the answer is basically however long they need to. The systems design - although never designed to - can handle this beautifully.
Doug
Superb.
MarK, thank you for the fantastic info and insights.
its great to hear that the "line of death" is much lower and a indeed much more complicated than thought just a week ago!
and the rover teams accomplishments even more impressive !
Well, here is a NASA update from today July 23 with a few more details. next com session set for Thursday July 26
NASA Mars Rovers Braving Severe Dust Storms
July 20, 2007
Updated July 23, 2007
NASA's Mars Exploration Rover Opportunity sent signals Monday morning, July 23, indicating its power situation improved slightly during the days when it obeyed commands to refrain from communicating with Earth in order to conserve power.
Dust storms on Mars in recent weeks have darkened skies over both Opportunity and its twin, Spirit. The rovers rely on electricity that their solar panels generate from sunlight. By last week, output from Opportunity's solar panels had dropped by about 80 percent from a month earlier.
Rover controllers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., commanded Opportunity last week to go into a very low-power state and to communicate only once every three days. The rover transmitted a small amount of information today. Next scheduled transmission will be Thursday, July 26, though controllers may command Opportunity to send information on Tuesday, July 24.
Meanwhile, communications from Spirit over the weekend indicated that the sky had cleared slightly at Spirit's location on the other side of Mars from Opportunity.
"The outlook for both Opportunity and Spirit depends on the weather, which makes it unpredictable," said JPL's John Callas, project manager for both rovers. "If the weather holds where it is now or gets better, the rovers will be OK. If it gets worse, the situation becomes more complex.
The MERs continue to shine as examples of truly superior systems engineering, all right. If I wasn't so far along on my topic already, I'd change my thesis subject to them. Maybe one of my classmates who are still looking for an idea might be interested.
Absolutely incredible machines, these little rovers. Blessed with a special genius.
I am in awe..... they are our Martian Voyagers... always striving to phone home........
Thanks Stu for the prose. Thanks Mark for the insight and updates.
Craig
It would be really cool if Spirit (since its situation is a bit better) could take a 3 color panorama right now. It could be heavily binned, since the purpose would be to show the overall scene in the dust storm, not resolve fine details. But whether it was a partial or a 360 degree pan, it would be a really nice addition to the MER collection.
I'm tempted to give in to a small sigh of relief, but the last time I did, the storm regained strength. If we do see yet another peak on the graph, I won't be nearly as worried as the last time. It's absolutely amazing that Opportunity was power positive through this last peak.
I don't remember anyone posting a link to http://themis.asu.edu/dustmaps/ of the dust storm. I discovered it today while looking for news on the storm.
Mark's updated the figures a little
We're now at the point in the decay where during the last decay - we had another outburst.
Doug
Best news for a long time!
Anyone else noticed this "stain" in the centre of Oppy's tracks as seen on the new pancam shots..?
Looks like the removal of a lighter coloured crust rather than any sort of staining to me. Some MI's would help.
The last horizon survey image ( which I think is the one you've posted there ) was actually from 1235, 8 sols ago - and is infact - when calibrated - the darkest slice of this cake
http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20070720a/Opportunity_horizon_br.jpg
Doug
Was using the word "stain" v v loosely. Wasn't actually suggesting that Oppy had.. well, you know...
The last horizon survey image ( which I think is the one you've posted there ) was actually from 1235, 8 sols ago - and is infact - when calibrated - the darkest slice of this cake
Really? Took it off the latest set of pancams released. Oh. B****r. I'll get me coat.
Well - I think it is - what's the actual file name of any one of the three files involved? Somewhere out there ( and I can't find it now..grrr) is a website where you drop the file name in and it converts it to the information for you. That - or using MMB - will tell you when the image was taken.
Doug
http://www.tnni.net/~dustymars/Observing_Mars_6
Since 1971, the year of the "Great Dust Storm of Mars," the ALPO Mars Recorders have suspected that these disturbances came in pairs. We have seen that in 1971 a major dust storm occurred on 213° Ls, followed by a "planet encircling" dust storm on 259° Ls. Again, in 1973 a major storm began on 244° Ls and was followed by a "planet encircling" storm on 300° Ls and [Martin, 1974]. The Viking Lander recorded two "planet encircling" storms on 204° and 268° [Tillman, 1988]
This is only the first big storm this season. At present, it's 282° Ls. And the big 1971 storm began to dissipate by 314° Ls. Still a long way to go...
Thanks for the info, OWW...
So now the question would be, once this storm's abated, do the Opportunity planners take a dip into Victoria, with the risk of getting caught somewhere less pleasant towards the end of a potential 50-60 day window, or sit still for two months with at least the potential for no more bad weather (is storm #2 chance or certainty?) and the risks that accompany an aging rover?
Andy, glad to not be decision-making.
Why would being in the crater be worse than being outside?
Because being flat on the plain you get the maximum indirect illumination of the arrays by the dust. On a slope - that will drop off (which every direction the slope is)
With clear skies and 800 Whrs, it doesn't really matter given that the slope runs down to the East (better power in the morning, but lower power in the evening) but with almost all the power currently coming from the difuse route - you want to be flat as you can.
Doug
Reading over the http://marsrovers.jpl.nasa.gov/mission/spacecraft_rover_energy.html, I found this chestnut:
I expect it wouldn't have amounted to a great loss of power if Oppy had been on the planned ingress route to the white layer. Being inside the crater would mean that the apparent horizon as viewed from the rover would be higher than the true horizon, so less sky would be visible. But the white layer is only 4 metres or so vertically inside the crater. The nearest cliffs to the expected ingress route are on Cabo Verde, about 30 m away (recall that they don't plan to drive near any cliffs!). That means (allowing for the height of the solar panel deck above the ground) that only 6 or 7 degrees of the horizon towards Verde would be obscured. Similarly, because of the tilt of the crater slope, a "sliver" of sky very roughly 15 degrees maximum width at the near rim and tapering to zero width at the far rim would be obscured.
You could imagine working out this way what percentage of sky, or how many steradians, would be obscured at the expected white layer study sites. No doubt an accurate elevation model would help here. I very crudely estimate a fraction 0.13 of the sky would be obscured at the white layer.
But there are more factors than just solid angle obscured. The solar arrays are much less sensitive to sky illumination from near the horizon than from overhead, just because light from near the horizon strikes the arrays at a glancing angle. Thus to estimate the power loss you must multiply that 0.13 fraction by a small geometrical factor, which is going to be something like the sine of the typical altitudes of obscured sky - that works out to another factor or order 1/10. Also, from the latest pancam images the sky appears to grow darker near the horizon. Therefore you get down to the 1% order of magnitude for total loss of power at the white layer.
Of course, if levels are truly critical, then even a couple percent reduction (like from 100 Whrs to 98 Whrs) could conceivably be fatal. Still, this likely wouldn't have been very important. I could see us entering Victoria soon after power levels allow mobility.
But, when the storm(s) end, wouldn’t more dust settle on Oppie inside the sheltered crater than on the rim? And wouldn’t there be less wind down there to remove said dust?
Months, not weeks...
The storm started in Aug or Sept 71. When Mariner arrived in November, most of the surface was hidden except for south polar cap and the top of the Tharsis volcanos and Olympus. Craters were visible as bright circular spots due to increased scatter from the deeper dustier atmosphere compared with adjacent higher terrain, as was Valles Marineris. After proving that their pre-planned mappign and observation sequences were near worthless, they replanned repetitive storm observation sequences and mapping tests to see how things were clearing. They finally started systematic mapping of the planet in January 72, starting with the least dusty high southern latitudes and progressively moving northwards.
Are they calling this a global event yet?
I haven't heard that term used in public yet, Ed. This storm seems not to have engulfed the entire planet so far. It has, however, encircled the planet.
The http://themis.asu.edu/dustmaps/ has been updated with an atmospheric opacity map for July 22-24. Per the latest map, it appears that opacity has improved somewhat for both rovers. But it's not obvious yet that the storm is dying as of Opportunity sols 1243-1244.
Big storms used to be called global, but Viking and later data showed that that was not strictly true as polar region dust levels are low enough the surface remains visible. Some papers <late 80's?> called the 1971 greatest-ever storm as truely global, while calling other storms as "globe encirclig"
Most pre-1971 storms were not observed well enough to make a clear distinction, and it's likely storms occured during perehelic solar conjunctions and the long periods when Mars is on the far side of the sun and until CCD imaging and advanced amateurs, was essentially not being observed at all.
The basic fact is that the historical record of storm statistics stinks.
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