Dust Storm- Opportunity EOM, the end of the beginning of a new era in robotic spaceflight Options

[marsophile]

https://mars.nasa.gov/msl/mission/instrumen...onsensors/rems/

Maximum daily ground temperature from REMS now above freezing. This suggests a clearing at least at the Curiosity site. Being a worry wart, I am now wondering if, ironically, Opportunity might overheat the warm electronics box while in fault mode with no human supervision.

[djellison]

There is no risk of Opportunity overheating. That would require an amount of power than would guarantee reliable communication with Earth.

[Fran Ontanaya]

https://mars.nasa.gov/msl/mission/instrumen...onsensors/rems/

As a side note, those conditions are above the triple point aren't they? Above 611 pascals and 0ºC during the day.

[mcaplinger]

As a side note, those conditions are above the triple point aren't they? Above 611 pascals and 0ºC during the day.

It's a sol-average pressure so you can't tell if the triple point was exceeded at some point diurnally, not that it would be so amazing if it was.

[serpens]

Even of it is the important variable is the absolute humidity. The actual amount of water vapour in the atmosphere so in this environment being above the triple point for a brief period would be of passing interest only.

[xflare]

I wonder if we will get another twitter/internet false alarm today

Attached thumbnail(s)

 

[djellison]

https://www.jpl.nasa.gov/news/news.php?feature=7227

"When the tau level [a measure of the amount of particulate matter in the Martian sky] dips below 1.5, we will begin a period of actively attempting to communicate with the rover by sending it commands via the antennas of NASA's Deep Space Network. Assuming that we hear back from Opportunity, we will begin the process of discerning its status and bringing it back online........

.....If we do not hear back after 45 days, the team will be forced to conclude that the Sun-blocking dust and the Martian cold have conspired to cause some type of fault from which the rover will more than likely not recover," said Callas. "At that point our active phase of reaching out to Opportunity will be at an end. However, in the unlikely chance that there is a large amount of dust sitting on the solar arrays that is blocking the Sun's energy, we will continue passive listening efforts for several months."

[Explorer1]

Reading this article a quote stuck out:

Engineers have carried out simulations predicting Opportunity’s current conditions. But they can’t account for how much dust remains—if any—on Opportunity’s solar panels. “The initial results [of the simulations] suggest that if tau was below about 1.5, there is a chance, depending on the dust loading on the panels, that we would be able to hear from Opportunity,” says Matt Golombek, the project scientist for the Mars Exploration Rover mission, which covers Opportunity and the now-defunct Spirit. “Although we have an estimate of the dust in the atmosphere, we have no idea how much dust is on the panels.”

Can't MRO just take a picture? I can guess that HiRISE is either in the wrong orbit to attempt imaging, or the resolution isn't quite high enough to resolve the rover as dust-covered or not, so it's not worth bothering to do? Would the surface be visible from orbit by now?

[mcaplinger]

Can't MRO just take a picture?

Have you looked at the images of Opportunity already taken by HiRISE? They are useless, IMHO, for assessing anything about the dust loading.

[marsophile]

Can't MRO just take a picture?

I think the answer is yes. AFAIK MRO is in a sun-synchronous orbit, so it should pass over every part of Mars in due course. It used to pass always at 2pm local time, but that may have changed. Even if the dust completely settles, there should be only a couple of microns of dust cover (as discussed in a previous post). I can't believe that would blanket the terrain in a way that would make the rover invisible. The only caveat I can think of is that Oppy is on a slope, which may help rather than hinder. IMHO, the only scenario in which Opportunity should be unrecoverable is if some combination of fault modes conspired somehow to place Oppy in an infinite loop of recovery efforts.
[EDIT: Evaluating the dust loading is a very different matter. Maybe it might be possible to look for a glint (specular reflection) from the solar panels?]

[fredk]

I suppose you may not need to resolve Oppy. In principle I could imagine comparing images of Perserverance Valley now with images before the storm under the same lighting conditions, and looking for signs of increased dust on the ground more generally. In principle.

In practice this sounds hard if not impossible. Can images at sufficiently similar lighting be obtained, especially given the changing season? And a current tau above the pre-storm level will surely confound a fair comparison due to the atmospheric dust contribution. And it's not clear how much of an increase of dust cover on the panels would be implied by some increase on the ground, due to the different surface characteristics.

[mcaplinger]

Maybe it might be possible to look for a glint (specular reflection) from the solar panels?

I think that's not possible given the orbital geometry; given the low tilt the imaging would have to happen around local noon, and MRO is in a roughly 3 PM orbit.

[djellison]

The one time we’ve seen a ‘glint’ via HiRise was off Spirit years after it died. And it was just lucky. I don’t believe it can be used quantitatively.

There is a huge back catalog of dust factor and tau data that’s been collated by people here.....one could quite easily see when cleaning events occur by plotting dust factor against Ls and looking for periods of general improvement.

[marsophile]

I think that's not possible given the orbital geometry; given the low tilt the imaging would have to happen around local noon, and MRO is in a roughly 3 PM orbit.

I think if an orbital pass was chosen to be about 22.5 degrees to the east of Opportunity, the geometry might be about right to hope for a reflection, since 3pm should mean a sun angle of 45 degrees from the zenith. Of course it would still take careful planning and a lot of luck.

[mcaplinger]

I think if an orbital pass was chosen to be about 22.5 degrees to the east of Opportunity...

I think that would be way off nadir, since from the MRO orbit the limb is only about 27 degrees of longitude from nadir. But I haven't studied the geometry carefully, and if there was an observed glint from Spirit there must be some way to make it work, though I don't remember what Spirit's tilt was.

However, I still argue that it's not diagnostic at all anyway.