OK, time to hear about dust and Opportunity and other Mars missions. #marsduststorm
#MarsDustStorm Visuals here (reposting for threading) nasa.gov/marsduststormt…
John Callas: There's a severe dust storm on Mars that is threatening Opportunity. The project team is very concerned. The vehicle has fallen asleep. Timeline:
May 30: MRO saw first indication of dust storm and notified MER team.
Indeed we saw increases in atmos opacity.
May 30: MRO saw first indication of dust storm and notified MER team.
Indeed we saw increases in atmos opacity.
Callas: On June 2, tau (opacity was 0.6). Next day it was 1.5. On Monday morning, June 4, we decided to reconfigure rover for low power operation. We measured tau at a little over 2, energy production had dropped to 345 watt hours. Next day, did another low power plan
Callas: We were unable to get another direct measurement of tau because it was so high; power dropped to 133 watt hours.
Our concern level continued to increase. On June 6, we decided to do a 2-day plan with no comms til second day as a power saving measure.
Our concern level continued to increase. On June 6, we decided to do a 2-day plan with no comms til second day as a power saving measure.
Callas: We do have to maintain *some* level of activity on the rover, because activity is what keeps the rover warm. On Friday we did a three-sol low power plan, nothing except an uplink of tau and a UHF relay with MRO. We did get it down on the ground on Sunday June 10.
Callas: Atmospheric opacity on June 10 was estimated at 10.8, an all-time high. It's completely black. Energy production on rover was measured at only 22 watt hours. I made decision to declare a spacecraft emergency because the rover would drop into a low power fault.
Callas: In a low power fault, rover turns off everything except a master clock, and does nothing but trickle power into batteries. We have heard nothing since then. We believe rover has gone to sleep, and rover will remain in that mode until batteries reach a charge threshold.
Callas: We're in a waiting mode, listening every day. Going forward, our concern is temperature on the rover, because it's inactive. Good news is that dust storm keeps things warmer, and it's going into summer season. We believe rover should stay above min operating temps.
Callas: One less complexity: If rover is generating less than 22Wh, then it won't have enough power to maintain clock, and rover will forget what time it is. Then it will have a clock fault. Will use power levels on solar arrays to "learn" that it's daytime, and will try comms.
Now onto Rich Zurek, who will talk about question of why major dust storms occur some years and not others.
Zurek: Planet encircling storms were observed by spacecraft on 2001 and 2007, but no such event has happened since then. This one will become one such event.
Zurek: On May 30 it was just a small local storm, noticed by MARCI team, which produces daily global weather maps.
On June 1 it headed south toward Opportunity.
Dust haze is now spread across a quarter of Mars. It is now a "dust event." Curiosity is seeing dust haze, too.
On June 1 it headed south toward Opportunity.
Dust haze is now spread across a quarter of Mars. It is now a "dust event." Curiosity is seeing dust haze, too.
Zurek: As dust expands, it absorbs sunlight, heating and producing a positive feedback cycle. Dust has now reached high altitudes. We're doing integrated observations with all Mars spacecraft to follow how the dust storm develops.
Jim Watzin, representing HQ. Regardless of how this turns out, this little rover has turned out to be an invaluable asset. Very briefly mentions InSight. I hope someone asks about that.
Mike Wall Q: How long can Opportunity last? How is this different from Spirit?
Callas: Spirit was going into winter; Opportunity is going into summer -- as soon as sky clears it'll have ample power.
Callas: Spirit was going into winter; Opportunity is going into summer -- as soon as sky clears it'll have ample power.
Callas: Models suggests rover hits a steady state temperature, with heating from its 8 internal Radioisotope Heater Units which provide 1 watt heat each from plutonium decay. Minimum allowable temp is -40C. We expect to hit as low as -36C
Marcia Dunn: Can rover get covered with dust? What about Curiosity?
Callas: Amount of accumulation is a monolayer of dust. There is concern that vehicle will get dusty.
Zurek: Curiosity is actually doing science, looking for dust movement inside crater. They're not too worried.
Callas: Amount of accumulation is a monolayer of dust. There is concern that vehicle will get dusty.
Zurek: Curiosity is actually doing science, looking for dust movement inside crater. They're not too worried.
And that's just NASA! ESA has two orbiters, and ISRO has one at Mars. Quite a fleet.
Joe Palca: How did Opportunity do in 2000 dust storm [he means 2007]? What's effect of old battery?
Callas: We were able to maintain sequence control throughout storm, but we did have periods where we chose not to communicate for 4 days.
Batteries are still at 85% capacity
Callas: We were able to maintain sequence control throughout storm, but we did have periods where we chose not to communicate for 4 days.
Batteries are still at 85% capacity
Callas: "They really are the finest batteries in the solar system." Still at 85% capacity even though they're 15 years old.
Zurek: There's huge variability in tau across planet. Opportunity has 10.8 but at Curiosity it's just 2 or 3 though it's rising. We're hoping skies were open up. Also storms often move past Meridiani; it didn't this time, it stalled.
Sarah Kaplan: How do these storms start?
Zurek: A lot like Earth storms -- local dust lifting. But on Mars dust lofts itself to high altitudes because of solar heating warming air with dust. The higher elevation it is, the longer it will take for it to subside.
Zurek: A lot like Earth storms -- local dust lifting. But on Mars dust lofts itself to high altitudes because of solar heating warming air with dust. The higher elevation it is, the longer it will take for it to subside.
Alex Witze: How will InSight landing be affected?
Watzig: InSight's navigation is not affected by dust. We can fly right through it during landing.
Zurek: Storm is not expected to last, but will a second storm develop later in the year? It's rare but we've seen it
Watzig: InSight's navigation is not affected by dust. We can fly right through it during landing.
Zurek: Storm is not expected to last, but will a second storm develop later in the year? It's rare but we've seen it
Zurek: InSight thinks they have margins to adequately deal with all possibilities -- global dust storm, regional dust storm.
Jonathan Amos: What's health situation of the rover, other than power situation?
Callas: It's in excellent health. We're doing 2-wheel steering instead of 4 because of steering actuator issues, but otherwise fine.
Callas: It's in excellent health. We're doing 2-wheel steering instead of 4 because of steering actuator issues, but otherwise fine.
Irene Klotz: Science update on what Opportunity was doing prior to storm?
Callas: Working at Perserverance Valley, which looked from orbit like it might be water-carved. We're exploring it, are halfway down, and are testing origin hypotheses -- water vs wind.
Callas: Working at Perserverance Valley, which looked from orbit like it might be water-carved. We're exploring it, are halfway down, and are testing origin hypotheses -- water vs wind.
Callas: Once we're done with that, we want to work further down the rim to look at crater's layers.
Zurek: This is a good example of how interpretations that seem easy from orbit get a lot more complicated once you're actually on the ground. "Ground truth is a good thing."
Zurek: This is a good example of how interpretations that seem easy from orbit get a lot more complicated once you're actually on the ground. "Ground truth is a good thing."
Alan Boyle: How is the team handling it?
Callas: It is concerning. This team has a very strong bond with the rover, we have a very tight emotional connection with it. We anthropomorphize this rover. It's like we have a loved one in a coma in the hospital.
Callas: It is concerning. This team has a very strong bond with the rover, we have a very tight emotional connection with it. We anthropomorphize this rover. It's like we have a loved one in a coma in the hospital.
Callas: We're very concerned. By no means are we out of the woods here. It's threatening. We have no idea how long it will last. We are all concerned, and you can see it in the team members.
Zurek: Opportunity is in a windy place, and as long as dust isn't being lifted locally, the wind will actually clean off the panels, as has happened several times in the past.
Zurek: It can take several weeks to a few months for dust to come out of the atmosphere after a planet encircling event.
Leo Enright: I'm wondering about collateral damage to other missions. For MAVEN, were there plans for a deep dip? Or dust fall on Curiosity?
Dave Lavery: With regard to orbiters, we don't expect any issues from the storm, they're above it and will be learning a lot.
Dave Lavery: With regard to orbiters, we don't expect any issues from the storm, they're above it and will be learning a lot.
Lavery: As for Curiosity, we have already noticed a darkening of the skies. Because it is nuclear power, we don't have power concerns. Only thing that could possibly concern is could dust be deposited on optics? At this point we don't have any concern.
Callas: Reminds that a low power state is actually normal for Opportunity -- they do it every day, call it Deep Sleep mode. Only difference is that it wasn't commanded this time.
Lisa Grossman: what data are you taking of storm?
Zurek: Infrared data tells us about particle sizes. We're looking at atmosphere at many levels. MAVEN is dipping down to 160 km at moment. They're safe, and it's interesting to see response of upper atmos to lower atmos.
Zurek: Infrared data tells us about particle sizes. We're looking at atmosphere at many levels. MAVEN is dipping down to 160 km at moment. They're safe, and it's interesting to see response of upper atmos to lower atmos.
Callas: We had very good dust factor so our energy production was excellent going in to this time. We'd already taken steps to maximize energy production anyway. There were no real measures to take, and in hindsight, nothing we could do to set up better.
Zurek: We've been trying to be prepared for this storm, define operations sequences that we'd implement if the dust got high in the atmosphere, but much of it was to continue standard observations so we could catch the beginning of it.
Callas: When designing Opportunity, we gave consideration to cleaning methods for solar panels, but in the end, the best solution was to build bigger solar panels. It's worked really well for us so far.
(If you look at early concepts for Opportunity, you'll see much smaller solar arrays. They added those bat-wing-like extensions later in development to dramatically increase array extent. In hindsight a choice that enabled its incredible longevity.)
Oooh a good question, asking Zurek to compare and contrast what it probably looks like to the opening of The Martian.
Zurek: Wind speeds are high, but you're not going to be able to blow a spacecraft over with it.
Zurek: Wind speeds are high, but you're not going to be able to blow a spacecraft over with it.
Zurek: surface winds near Opportunity may not be very strong; it's high winds at altitude that are spreading it globally.
Briefing is over. I'm attending a conference right now but can try to answer some questions throughout the day. #MarsDustStorm
But I'll say I actually feel very good about this briefing. The fact that Opportunity is not predicted to drop below its allowable temperature for the foreseeable future is EXTREMELY GOOD NEWS.
JPL's Mars Storm Watch page: mars.nasa.gov/weather/storm-…
@threadreaderapp could you please unroll this thread for me?
