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

[Tom Dahl]

Wow, an amazing image to have captured yourself!

[JRehling]

Thanks! I wish the dust storm had not been in the way, and I know that many others feel the same. Perhaps it will fade soon.

[marsophile]

Hmm. Although the seasonal upward trend is similar, the pressure during this dust storm, as measured by REMS, is about 20 pascals lower than at a similar period during the last three Martian years.

Pressure (pascals) for LS 198-208:
2018 779-807

2016 798-823
2014 802-829
2012 805-830

Sources:
https://mars.nasa.gov/msl/mission/instrumen...onsensors/rems/
https://github.com/the-pudding/data/blob/ma...ars-weather.csv

[serpens]

I wouldn't read too much into this. The Gale crater temperature/pressure during the course of a sol is governed by the crater topography so that during the day as temperature increases atmosphere flows out of the crater reducing the air pressure while at night colder air settles into the crater from the rim. The drop in upper atmosphere temperatures and increase in lower atmosphere temperatures due to the dust storm has probably had an effect on this cycle.

[marsophile]

The lower pressure this Mars year seems to have preceded the dust storm by several months.
For example at LS 135:

2018 727

2016 747
2014 750
2012 N/A

The 2018 LS 135 was on 02-27. Perhaps an overall lower pressure is predictive of the year in which a major dust storm is likely to occur?

[mcaplinger]

The lower pressure this Mars year seems to have preceded the dust storm by several months.

According to http://cab.inta-csic.es/rems/wp-content/up...RATION_PLAN.pdf the pressure sensor is only required to be accurate to 10 Pa at beginning of life and 20 Pa at end of life (end of the primary mission, I presume.) It may be doing better than that, but I'd be reluctant to draw any conclusions from absolute pressure measurements over long time scales without taking possible instrument drift into account.

[marsophile]

I'd be reluctant to draw any conclusions from absolute pressure measurements over long time scales without taking possible instrument drift into account.

Good point! Based on your comment I took a look at when the larger pressure differential occurred.

Earth_date ls month pressure

2017-08-18 048 Month 2 881
2015-10-01 048 Month 2 901

2016-09-12 220 Month 8 859
2014-10-24 220 Month 8 862

The deficit in pressure from the previous year seems to have gradually widened over a period of about a half Martian year, and to have stayed roughly constant since then. This could be consistent with instrument drift. It will be interesting to see where it goes from here. It's a pity there is no ongoing way of calibrating the instrument.

[JRehling]

Can radio occultation measurements from orbiters be used to measure pressure? That was how atmospheric density was measured in many other cases in the past, e.g., Voyager 1 and Titan.

[Deimos]

The interpretation of the pressure differences above might be different if the altitude change were considered: ~225 m in the Ls 48 comparison, but only ~89 m in the Ls 220 comparison. One would expect a more than 2% drop in the first case (little residual), but <1% in the second (residual increases slightly with time between those two specific points). Given the possibility for drift, interpreting any residual variation seems sporty.

[marsophile]

Just saw what looked like a brief downllink from Opportunity on DSN Now:

DOWN SIGNAL

SOURCE
OPPORTUNITY

TYPE
CARRIER

DATA RATE
1.10 Mb/sec

FREQUENCY

8.45 GHz

[EDIT: Now it is showing MAVEN as the source with similar data rate and frequency. Maybe it was some kind of switch-over glitch.]

[djellison]

You will regularly see very brief appearances of Opportunity 'locking up' briefly.

It's usually side bands from MRO, and less frequently MAVEN drifting thru the frequency we're looking at - and the receiver incorrectly locking up on it. We have to manually drop lock and then carry on looking - so briefly, it appears Opportunity is transmitting when it isn't.

[marsophile]

https://mars.nasa.gov/mer/home/

New status report and press release about the dust storm posted at the MER home page.
Misfortune for Opportunity but an opportunity for MAVEN.

Ever since the MAVEN orbiter entered Mars' orbit, "one of the things we've been waiting for is a global dust storm," said Bruce Jakosky, the MAVEN orbiter's princip[al] investigator.

[fredk]

Glimmer of hope from the latest MRO MARCI Weather Report that things might start improving:

Some atmospheric clearing was spotted over Noachis and Aonia Terra as the planet-encircling dust event transitioned to a decay phase.

[PaulM]

When spirit failed to restart when the spring came I was convinced by the official explanation that the electronics had been damaged by low temperatures. However it was also possible that spirit did not restart correctly because of an error in the software or hardware designed to carry out this recovery. I realize that insight has different hardware but I wonder if there has been a full end to end test of recovery from a flat battery and no sunlight using the insight reference hardware. The insight radio science experiment simply requires radio communications over more than two years to be successful. I wonder if insight would recover correctly in a similar scenario to that currently being endured by opportunity?

[mcaplinger]

I wonder if insight would recover correctly in a similar scenario to that currently being endured by opportunity?

No idea. Probably Giang Q. Lam, Scott Billets, Timothy Norick, and Richard Warwick. "Solar Array Design For The Mars InSight Lander Mission", 14th International Energy Conversion Engineering Conference, AIAA Propulsion and Energy Forum, (AIAA 2016-4520), https://arc.aiaa.org/doi/abs/10.2514/6.2016-4520 has some information, but it's behind a paywall.

I'm not sure if a worst-case global dust storm was a credible contingency for InSight planning; I suspect not.