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#226 2018-02-20 22:21:03

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
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Re: Opportunity & Spirit **8** - ...More...

2 years and this is the first visit to post about the little engine,,,Rover that could...

http://www.marsdaily.com/reports/Mars_R … s_999.html

That warrantee expired a long time ago and its still making us all want to go to mars still..

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#227 2018-06-10 19:46:59

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

Something that Curiosity is not going to be as serverly effected by in a https://www.space.com/40847-mars-dust-s … rover.html

aHR0cDovL3d3dy5zcGFjZS5jb20vaW1hZ2VzL2kvMDAwLzA3Ny8wMTIvb3JpZ2luYWwvbWFycy1kdXN0LXN0b3JtLW9wcG9ydHVuaXR5LWp1bmUtMjAxOC5qcGc=

The intesnsity is still on the up swing and will make the rover go into energy saver mode as it gets thicker.

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#228 2018-06-13 21:07:48

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

The storm is increasing and the rover is in a shutdown mode as the amount of solar is putting the rover into a cold condition as it needs to be heated to keep alive.

Here’s what NASA’s Opportunity rover saw as it was swallowed up by the Martian dust storm

AAyARkb.img?h=587&w=799&m=6&q=60&o=f&l=f&x=442&y=314

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#229 2018-06-14 17:39:16

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

This may be the end of the little rover that could:

https://en.wikipedia.org/wiki/Opportunity_(rover)

This class of rover has two rechargeable lithium batteries weighing 7.15 kg (15.8 lb) each, each composed of 8 cells with 10 amp-hour capacity .
In Eagle crater the cells were producing about 840 watt-hours, but by Sol 319 in December 2004, it had dropped to 730 watt-hours.
During its first winter power levels dropped to under 300 watt-hours per day for two months, but some later winters were not as bad
When fully illuminated, the rover triple junction solar arrays generate about 140 watts for up to four hours per Martian day

mars-opportunity-rover.jpg

NASA noted that as the storm blotted out the sun, Opportunity’s power supply dropped steadily: from 645 watt-hours, to 345, and finally to merely 22 watt-hours — little more than what a large iPhone’s battery holds.

It’s been 4 days since a signal was heard from Opportunity. The storm, which was first detected on May 30, now blankets 14-million square miles (35-million square kilometers) of Martian surface -- a quarter of the planet an area greater than North America.

Louis you need to remember that the solar panel does not put out power until its above the 70% levels with it charging the batteriy during the around or aproximate 3hr period of a day and that will not be achieveable once the amount of light drops.

The previous storm had an opacity level, or tau, somewhere above 5.5; this new storm had an estimated tau of 10.8 as of Sunday morning. See the image from earlier in the page.


NASA’s Opportunity rover is fighting for its life in a Martian dust storm

The growing storm image:
UBNWQLECYM3FJI7UUFULKVRM2Y.gif

Since the storm began two weeks ago, the amount of light the spacecraft receives has dropped to less than 1 percent of normal levels. Energy production has fallen from hundreds of watt-hours a day to almost nothing.

Mars Exploration Rover project manager John Callas, team is operating under the assumption that the charge in Opportunity's batteries has dipped below 24 volts and that the rover has entered a low-power fault mode, when all subsystems except the mission clock are turned off.

Opportunity's batteries — even though they are 15 years old, they are still working at 85 percent of their capacity.

The clock is programmed to rouse the rover at periodic intervals to check whether light levels are sufficient to wake up — a state called “solar groovy.” But the storm is still growing and should encircle the planet in a matter of days. NASA expects that it will be weeks, if not months, before the dust clears enough to allow the spacecraft to turn back on.

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#230 2018-06-15 15:30:21

GW Johnson
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Re: Opportunity & Spirit **8** - ...More...

That "less than 1% of normal levels" of insolation in a big dust storm does not surprise me.   Not at all.  It can get really black underneath a typical North American desert dust storm. 

Louis has never seen such a thing,  coming from the UK as he does,  and so he does not believe it can really get that dark.  But he is wrong.  I have seen it,  many times.  I grew up with it. 

Depending upon how long this lasts,  and just how cold the little rover soaks out,  we will probably lose the little guy. 

Any exploration site,  base,  or other settlement we put on Mars must be prepared for this.  Any significant darkening is going to render the panels unable to generate voltage. 

These things on Mars can last anywhere from hours to many months.  The storm that already blanketed all of Mars when the 1969 orbiter arrived lasted 9 months after that orbiter arrived. 

THAT is why you take two sources of power (solar and nuclear),  and why you make each one redundant by a factor of 2,  and preferably 3.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#231 2018-06-15 15:36:35

Oldfart1939
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Re: Opportunity & Spirit **8** - ...More...

There is also a reason why the research camps in Antarctica are not depending on solar power. I give GW a "two thumbs up," for his comments.

Last edited by Oldfart1939 (2018-06-15 15:37:09)

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#232 2018-06-15 16:54:05

louis
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Re: Opportunity & Spirit **8** - ...More...

Your storms are probably 100 x more powerful than what is happening on Mars. Wind on Mars is really weak. We do have lots of tornadoes in the UK you may be surprised to learn. smile

This from the NASA website doesn't suggest that 99% reduction in insolation ever occurs on Earth, or if it does, it must be a very shortlived phenomenon, otherwise the reduction in temperature would be much more dramatic than one degree celsius (in most parts of the world night time temperatures see a drop of several degrees and , as we see in polar regions, if insolation reduces by that amount for several weeks you get a very sharp drop in temperatures)...

https://www.giss.nasa.gov/research/briefs/miller_01/

I'd like to see something a bit more scientific as to what the levels of insolation on Mars are during dust storms. What is received by a dusty and deteriorated solar panel does not equate to insolation. Everything I have previously read suggests 20% of normal is the mark of a serious worst-case dust storm.

Yes, they can go on for a very long time. But do they carry on at 20%?  No. I doubt that very much.  That's a very low point which is probably only rarely exceeded.

GW Johnson wrote:

That "less than 1% of normal levels" of insolation in a big dust storm does not surprise me.   Not at all.  It can get really black underneath a typical North American desert dust storm. 

Louis has never seen such a thing,  coming from the UK as he does,  and so he does not believe it can really get that dark.  But he is wrong.  I have seen it,  many times.  I grew up with it. 

Depending upon how long this lasts,  and just how cold the little rover soaks out,  we will probably lose the little guy. 

Any exploration site,  base,  or other settlement we put on Mars must be prepared for this.  Any significant darkening is going to render the panels unable to generate voltage. 

These things on Mars can last anywhere from hours to many months.  The storm that already blanketed all of Mars when the 1969 orbiter arrived lasted 9 months after that orbiter arrived. 

THAT is why you take two sources of power (solar and nuclear),  and why you make each one redundant by a factor of 2,  and preferably 3.

GW


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#233 2018-06-15 20:21:09

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

https://mars.nasa.gov/

science that is being conducted:

DustStorm_Jun2018_ScienceObservations-1440.jpg


The curiosity rover is seeing the dust in the atmosphere as well.

PIA22520-600.jpg

These two views from NASA’s Curiosity rover, acquired specifically to measure the amount of dust inside Gale Crater, show that dust has increased over three days from a major Martian dust storm june 7 - june 10th.

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#234 2018-06-15 22:37:29

GW Johnson
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Re: Opportunity & Spirit **8** - ...More...

Louis,  I do not understand your predilection for ignoring real data that you do not like.  You are entitled to your own opinions.  You are NOT entitled to your own facts. 

Look at the second quote in Spacenut's post 229 above.  That measurement (!!!) is where the 1% figure that I quoted came from. 

And yes,  the temperature here on Earth does drop several degrees when it gets so very black underneath any kind of dark cloud,  including a dust storm.  The effect is mitigated some by the wind,  which convects heat from the adjacent warm ground. 

Whether the winds on Earth are more powerful than the winds on Mars (and they are) makes no difference to the dimming of insolation in a dust storm.  The available data clearly show dust storm events that can engulf the entire planet miles deep in dust.  All that really matters to dimming is those miles,  once the dust is "dense enough".  And it doesn't really take all that much density.

Remember the 1969 event:  even Olympus Mons was covered up in the storm,  and its peak is about 50,000 feet (17 km) higher than datum on Mars.  We did not see it or the other volcanic peaks until some months after the orbiter arrived.  As I said:  miles deep in dust.  For several months.

And that's why the light gets so dim.

GW

Last edited by GW Johnson (2018-06-15 22:45:57)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#235 2018-06-16 18:12:49

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

https://mars.nasa.gov/weather/storm-watch-2018/

https://mars.nasa.gov/resources/21914/t … june-2018/

Mars Reconnaissance Orbiter’s Mars Colour Imager (MARCI) camera. MARCI acquires a global view of the Red Planet and its weather patterns every day and can tell us about seasonal and yearly changes in climate. It also observes dust storms and changes in the polar cap and makes ultraviolet observations to detect variations in ozone, dust, and carbon dioxide in the atmosphere. MARCI observes these processes on scales of tens of kilometers.


https://mars.nasa.gov/news/1854/the-fac … st-storms/

Big Dust Storm Blows up on Mars

Telescope view of mars:

Mars-May-31-John-Boudreau.jpg

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#236 2018-06-16 19:01:27

louis
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From: UK
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Re: Opportunity & Spirit **8** - ...More...

Yep. We can still make out features. No way is that 99% obscurity.  People are confusing obscurity increase with insolation reduction. The two have a relationship but it is not one for one owing to diffusion of incoming solar radiation. I have not found a single scientific paper suggesting the insolation reduction is greater than 80% max in a dust storm for any significant length of time...let's say more than 1 sol. If you can find one, I'll be interested to read it.


SpaceNut wrote:

https://mars.nasa.gov/weather/storm-watch-2018/

https://mars.nasa.gov/resources/21914/t … june-2018/

Mars Reconnaissance Orbiter’s Mars Colour Imager (MARCI) camera. MARCI acquires a global view of the Red Planet and its weather patterns every day and can tell us about seasonal and yearly changes in climate. It also observes dust storms and changes in the polar cap and makes ultraviolet observations to detect variations in ozone, dust, and carbon dioxide in the atmosphere. MARCI observes these processes on scales of tens of kilometers.


https://mars.nasa.gov/news/1854/the-fac … st-storms/

Big Dust Storm Blows up on Mars

Telescope view of mars:

http://wwwcdn.skyandtelescope.com/wp-co … udreau.jpg


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#237 2018-06-16 19:42:21

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

post 228 image is the increase obscurity with insolation reduction and to this point the rover has not called back home as the intensity of the storm is still continuing.

https://ntrs.nasa.gov/archive/nasa/casi … 012929.pdf

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#238 2018-06-16 21:20:07

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

Here is the day to day power and images that I can find:

The tau and the telescope view are for differnet days as the storm was approaching

may 30th Opportunity’s batteries were delivering 645 watt hours
may 31 Mars-May-31-John-Boudreau.jpg

jun 1st   Opportunity’s energy levels had dropped to 345 watt hours
jun 2nd  Opportunity’s drops farther to 133 watt hours this is at a tau of 5 ish for solar being able to charge the battery

while the current storm had an estimated tau of nearly 11 as of June 6
jun 6th Mars-Oppy-MRO-June-storm-NASA_JPL_MSSS.jpg

science operations on June 8 suspended

jun 9th Mars-dust-storm-before-after-Damian-and-Anthony.jpg

jun 11  Two days later, a final transmission came in from Opportunity showing the energy level had dropped to just 22 watt hours, which would be expected to trigger a low-power fault mode in which everything but the mission clock is turned off.

Opportunity rover on June 12 but did not hear back probably because the charge in its batteries has dropped below 24 volts.


“The good news there is the dust storm has warmed temperatures on Mars. We’re also going into the summer season, and so the rover will not get as cold as it would normally.

The 2007 was a tau of 5.5 for the same rover:
Operations Strategies for the Mars Exploration Rovers During the 2007 Martian Global Dust Storm

estimated that the dust in the atmosphere prevented over 99.6% of direct sunlight from reaching the surface at the peak of the storm. Data collected indicated that solar array energy output was reduced to approximately 15% of maximum.

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#239 2018-07-08 14:54:41

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

Happy Birthday.... NASA's Mars Opportunity rover is celebrating its 15th birthday with a nap because of a giant dust storm. Look back at its unlikely journey.

No word has been given as to whether or not Nasa has given up yet on contacting the little rover that could...built to last just 90 Martian sols, or 92 Earth days.

5b3fddf542e1cc15113594a2-750-488.jpg

The rover blasted off from Kennedy Space Center at 11:18 p.m. on June 7, 2003.

5b3fddf242e1cc1511359492-960-1464.jpg

A Delta II Heavy launch vehicle carrying the rover Opportunity takes off from Launch Complex 17-B, at Cape Canaveral in Florida

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#240 2018-07-31 19:53:58

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

Saw news that the dust storm is starting to abate and slowly showing signs that landscape marking for mars are beginning to be visible.
It will be most likely a month or more before the little rover might possibly call home.

Nasa is making the most out of the opportunity taking advantage of a rare opportunity — global dust storms engulf the Red Planet just once every six or eight Earth years — to learn more about the Martian atmosphere and climate.

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#241 2018-08-01 22:23:05

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

https://en.wikipedia.org/wiki/Opportunity_(rover)

Solar array energy production throughout mission graphs on the page

A lot of variation between the date windows....

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#242 2018-09-12 20:03:57

SpaceNut
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Re: Opportunity & Spirit **8** - ...More...

The dust has begun to settle but the question is how much of it rests on the solar panels and will the light as it intensify get bright enough to bring the little rover back to life.

A new listening plan for Mars Opportunity rover

No signal from Opportunity has been heard since Sol 5111 (June 10, 2018), though NASA has approved a strategy for listening for the rover through January of 2019.

It is expected that Opportunity has experienced a low-power fault and perhaps, a mission clock fault and then an up-loss timer fault. The science team continues to listen for the rover either during the expected fault communication windows or listening over a broader range of times using the Deep Space Network Radio Science Receiver.

The science team is also sending a command three times a week to elicit a beep if the rover happens to be awake, and will soon be expanding the commanding to include "sweep and beeps" to address a possible complexity with certain conditions within the mission clock fault. These will continue through January of 2019.

The dust storm on Mars continues its decay with atmospheric opacity (tau) over the rover site continuing to decrease. Once the tau has fallen below an estimated measurement of 1.5 twice - with one week apart between measurements - a period of 45 days will begin representing the best time for us to hear from the rover.

We will also actively attempt to command the rover to communicate during the 45-day listening period to cover the clock fault condition.

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