Author Topic: Opportunity rover updates and discussion  (Read 19027 times)

Offline Star One

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Opportunity rover updates and discussion
« Reply #20 on: 02/18/2018 08:35 PM »
« Last Edit: 02/18/2018 08:35 PM by Star One »

Offline FutureSpaceTourist

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Re: Opportunity rover updates and discussion
« Reply #21 on: 02/23/2018 07:26 PM »
Quote
Feb. 15, 2018

Long-Lived Mars Rover Opportunity Keeps Finding Surprises

NASA's Mars Exploration Rover Opportunity keeps providing surprises about the Red Planet, most recently with observations of possible "rock stripes."

The ground texture seen in recent images from the rover resembles a smudged version of very distinctive stone stripes on some mountain slopes on Earth that result from repeated cycles of freezing and thawing of wet soil. But it might also be due to wind, downhill transport, other processes or a combination.

Opportunity landed on Mars in January 2004. As it reaches the 5,000th Martian day, or sol, of what was planned as a 90-sol mission (see related story), it is investigating a channel called "Perseverance Valley," which descends the inboard slope of the western rim of Endeavour Crater.

"Perseverance Valley is a special place, like having a new mission again after all these years," said Opportunity Deputy Principal Investigator Ray Arvidson of Washington University in St. Louis. "We already knew it was unlike any place any Mars rover has seen before, even if we don't yet know how it formed, and now we're seeing surfaces that look like stone stripes. It's mysterious. It's exciting. I think the set of observations we'll get will enable us to understand it."

On some slopes within the valley, the soil and gravel particles appear to have become organized into narrow rows or corrugations, parallel to the slope, alternating between rows with more gravel and rows with less.

The origin of the whole valley is uncertain. Rover-team scientists are analyzing various clues that suggest actions of water, wind or ice. They are also considering a range of possible explanations for the stripes, and remain uncertain about whether this texture results from processes of relatively modern Mars or a much older Mars.

Other lines of evidence have convinced Mars experts that, on a scale of hundreds of thousands of years, Mars goes through cycles when the tilt or obliquity of its axis increases so much that some of the water now frozen at the poles vaporizes into the atmosphere and then becomes snow or frost accumulating nearer the equator.

"One possible explanation of these stripes is that they are relics from a time of greater obliquity when snow packs on the rim seasonally melted enough to moisten the soil, and then freeze-thaw cycles organized the small rocks into stripes," Arvidson said. "Gravitational downhill movement may be diffusing them so they don't look as crisp as when they were fresh."

Bernard Hallet of the University of Washington, Seattle, agrees the alignments seen in images of Perseverance Valley are not as distinctive as the stone stripes he has studied on Earth. Field measurements on Earth, near the summit of Hawaii's Mauna Kea where the soil freezes every night but is often dry, have documented how those form when temperature and ground conditions are right: Soils with a mix of silt, sand and gravel expand more where the finer-grain material is most prevalent and retains more water. Freezing expands the soil, pushing larger particles up. If they move to the side, as well as down the general slope, due to gravity or wind, they tend to move away from the finer-grain concentrations and stretch out downslope. Where larger particles become more concentrated, the ground expands less. The process repeats hundreds or thousands of times, and the pattern self-organizes into alternating stripes.

Perseverance Valley holds rocks carved by sand blowing uphill from the crater floor, and wind might also be the key in sorting larger particles into rows parallel to the slope.

"Debris from relatively fresh impact craters is scattered over the surface of the area, complicating assessment of effects of wind," said Opportunity science-team member Robert Sullivan of Cornell University, Ithaca, New York. "I don't know what these stripes are, and I don't think anyone else knows for sure what they are, so we're entertaining multiple hypotheses and gathering more data to figure it out."

Every sol Opportunity keeps working may add information to help solve some puzzles and find new ones. For more information about Opportunity, visit:

https://www.nasa.gov/rovers

https://marsrovers.jpl.nasa.gov

https://www.nasa.gov/feature/jpl/long-lived-mars-rover-opportunity-keeps-finding-surprises

First image caption:

Quote
Textured rows on the ground in this portion of "Perseverance Valley" are under investigation by NASA's Mars Exploration Rover Opportunity, which used its Navigation Camera (Navcam) to take the component images of this downhill-looking scene.

The rover took this image on Jan. 4, 2018, during the 4,958th Martian day, or sol, of its work on Mars, looking downhill from a position about one-third of the way down the valley. Perseverance Valley descends the inboard slope of the western rim of Endeavour Crater. A view on the same sol with the rover's front Hazard Avoidance Camera includes ground even closer to the rover at this site. Opportunity was still working close by as it reached the mission's Sol 5,000 (Feb. 16, 2018).

In the portion of the valley seen here, soil and gravel have been shaped into a striped pattern in the foreground and partially bury outcrops visible in the midfield. The long dimensions of the stripes are approximately aligned with the downhill direction. The striped pattern resembles a type of feature on Earth (such as on Hawaii's Mauna Kea) that is caused by repeated cycles of freezing and thawing, though other possible origins are also under consideration for the pattern in Perseverance Valley.

The view is spans from north on the left to east-southeast on the right. For scale, the foreground rock clump in the lower right is about 11 inches (28 centimeters) in width.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for NASA's Science Mission Directorate, Washington.

Second image caption:

Quote
This late-afternoon view from the front Hazard Avoidance Camera on NASA's Mars Exploration Rover Opportunity shows a pattern of rock stripes on the ground, a surprise to scientists on the rover team. Approaching the 5,000th Martian day or sol, of what was planned as a 90-sol mission, Opportunity is still providing new discoveries.

This image was taken inside "Perseverance Valley," on the inboard slope of the western rim of Endeavour Crater, on Sol 4958 (Jan. 4, 2018). Both this view and one taken the same sol by the rover's Navigation Camera look downhill toward the northeast from about one-third of the way down the valley, which extends about the length of two football fields from the crest of the rim toward the crater floor.

The lighting, with the Sun at a low angle, emphasizes the ground texture, shaped into stripes defined by rock fragments. The stripes are aligned with the downhill direction. The rock to the upper right of the rover's robotic arm is about 2 inches (5 centimeters) wide and about 3 feet (1 meter) from the centerline of the rover's two front wheels.

This striped pattern resembles features seen on Earth, including on Hawaii's Mauna Kea, that are formed by cycles of freezing and thawing of ground moistened by melting ice or snow. There, fine-grained fraction of the soil expands as it freezes, and this lifts the rock fragments up and to the sides. If such a process formed this pattern in Perseverance Valley, those conditions might have been present locally during a period within the past few million years when Mars' spin axis was at a greater tilt than it is now, and some of the water ice now at the poles was redistributed to lower latitudes. Other hypotheses for how these features formed are also under consideration, including high-velocity slope winds.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for NASA's Science Mission Directorate, Washington.

Third image caption:

Quote
This image shows stone stripes on the side of a volcanic cone on Mauna Kea, Hawaii. The stripes are made of small rock fragments and they are aligned downhill as freeze-thaw cycles have lifted them up and out of the finer-grained regolith, and moved them to the sides, forming stone stripes.

This site is at about 13,450-foot (4,100-meter) altitude on the mountain. For scale, the rock cluster toward the bottom right of the image is approximately 1 foot (30 centimeters) wide. The image was taken in 1999 by R. E. Arvidson.

Such ground texture has been seen in recent images from NASA's Mars Exploration Rover Opportunity. For more details about "rock stripes" on Mars, see PIA22217 and PIA22218.
« Last Edit: 02/23/2018 07:27 PM by FutureSpaceTourist »

Offline Dalhousie

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Re: Opportunity rover updates and discussion
« Reply #22 on: 04/05/2018 07:52 AM »
This is a nice find, and we do see similar features in periglacial environments on Earth. I'll try and dig up some photos from northern Canada.  However one word of caution, these features are an order of magnitude smaller than the features called slope stripes on Earth. 
"There is nobody who is a bigger fan of sending robots to Mars than me... But I believe firmly that the best, the most comprehensive, the most successful exploration will be done by humans" Steve Squyres

Offline hop

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Re: Opportunity rover updates and discussion
« Reply #23 on: 06/09/2018 08:19 PM »
Opportunity is now in the midst of a very serious dust storm: https://www.jpl.nasa.gov/news/news.php?feature=7155

Quote
Opportunity Hunkers Down During Dust Storm

NASA Mars Exploration Rover Status Report

Science operations for NASA's Opportunity rover have been temporarily suspended as it waits out a growing dust storm on Mars.

NASA's Mars Reconnaissance Orbiter first detected the storm on Friday, June 1. As soon as the orbiter team saw how close the storm was to Opportunity, they notified the rover's team to begin preparing contingency plans.

In a matter of days, the storm had ballooned. It now spans more than 7 million square miles (18 million square kilometers) -- an area greater than North America -- and includes Opportunity's current location at Perseverance Valley. More importantly, the swirling dust has raised the atmospheric opacity, or "tau," in the valley in the past few days. This is comparable to an extremely smoggy day that blots out sunlight. The rover uses solar panels to provide power and to recharge its batteries.

Opportunity's power levels had dropped significantly by Wednesday, June 6, requiring the rover to shift to minimal operations.

This isn't Opportunity's first time hunkering down in bad weather: in 2007, a much larger storm covered the planet. That led to two weeks of minimal operations, including several days with no contact from the rover to save power. The project's management prepared for the possibility that Opportunity couldn't balance low levels of power with its energy-intensive survival heaters, which protect its batteries from Mars' extreme cold. It's not unlike running a car in the winter so that the cold doesn't sap its battery charge.There is a risk to the rover if the storm persists for too long and Opportunity gets too cold while waiting for the skies to clear.

Ultimately, the storm subsided and Opportunity prevailed. The Martian cold is believed to have resulted in the loss of Spirit, Opportunity's twin in the Mars Exploration Rover mission, back in 2010. Despite this, both rovers have vastly exceeded expectations: they were only designed to last 90 days each. Opportunity is in its 15th year; the team has operated the rover for more than 50 times longer than originally planned.

Full dust storms like this one are not surprising, but are infrequent. They can crop up suddenly but last weeks, even months. During southern summer, sunlight warms dust particles, lifting them higher into the atmosphere and creating more wind. That wind kicks up yet more dust, creating a feedback loop that NASA scientists still seek to understand.

Mars Reconnaissance Orbiter and two other NASA spacecraft orbiting the Red Planet --Odyssey and MAVEN -- routinely support rovers on the ground.

For more information about the Mars Exploration Rovers, visit:

https://mars.nasa.gov/mer/home/index.html
« Last Edit: 06/09/2018 08:20 PM by hop »

Online ChrisGebhardt

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Re: Opportunity rover updates and discussion
« Reply #24 on: 06/10/2018 02:01 PM »
Oppy talking to DSN via Goldstone right now.

Offline hop

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Re: Opportunity rover updates and discussion
« Reply #25 on: 06/11/2018 03:02 AM »
Updated https://www.nasa.gov/feature/jpl/opportunity-hunkers-down-during-dust-storm

Quote
NASA Mars Exploration Rover Status Report

Updated at 4:30 p.m. PDT on June 10, 2018

NASA engineers received a transmission from Opportunity on Sunday morning — a positive sign despite the worsening dust storm. Data from the transmission let engineers know the rover still has enough battery charge to communicate with ground controllers at NASA’s Jet Propulsion Laboratory in Pasadena, California. Science operations remain suspended.

Sunday's transmission was especially good news considering the dust storm has intensified in the past several days. A dark, perpetual night has settled over the rover's location in Mars' Perseverance Valley. The storm's atmospheric opacity — the veil of dust blowing around, which can blot out sunlight -- is now much worse than a 2007 storm that Opportunity weathered. 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.

Opportunity's team has requested additional communications coverage from NASA's Deep Space Network, a global system of antennas that talks to all the agency's deep space probes.

This latest data transmission showed the rover's temperature to be about minus 20 degrees Fahrenheit (minus 29 degrees Celsius). One saving grace of dust storms is that they can actually limit the extreme temperature swings experienced on the Martian surface. The same swirling dust that blocks out sunlight also absorbs heat, raising the ambient temperature surrounding Opportunity.

Engineers will monitor the rover's power levels closely in the week to come. The rover needs to balance low levels of charge in its battery with sub-freezing temperatures. Its heaters are vitally important to keeping it alive, but also draw more power from the battery. Likewise, performing certain actions draws on battery power, but can actually expel energy and raise the rover's temperature.

The rover has proved hardier than expected by lasting nearly 15 years, despite being designed for a 90-day mission.
MER folks on twitter noting this breaks the Viking record for tau
« Last Edit: 06/11/2018 03:03 AM by hop »

Offline Nomadd

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Re: Opportunity rover updates and discussion
« Reply #26 on: 06/11/2018 05:45 AM »
 I have a good excuse for not remembering what equipment could be permanently harmed by a complete loss of heat and power. It was 11 years ago that they talked about it.

Online Chris Bergin

Re: Opportunity rover updates and discussion
« Reply #27 on: 06/11/2018 09:02 PM »
ARTICLE: Opportunity hunkers down as dust storm descends over the intrepid little rover -

https://www.nasaspaceflight.com/2018/06/opportunity-dust-storm-descends-intrepid-little-rover/

By Chris Gebhardt

Offline speedevil

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Re: Opportunity rover updates and discussion
« Reply #28 on: 06/11/2018 11:15 PM »
Is there any reported Wh/Wh impact of - say - last time the weather was good, compared to today?

Clearly, heater demand may have gone down, but charging over the day is impacted more subtly than simply 'good day Wh/tau', as for example, diffuse light plays a bigger part and may extend the charging time a little.

Offline theinternetftw

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Re: Opportunity rover updates and discussion
« Reply #29 on: 06/12/2018 12:22 AM »
A quite good summary video giving perspective on the storm. Recommend pausing to read the twitter conversations with the NASA folks, which contain such gems as:

Quote
Day is night, viewed from 1000 feet deep in a coal mine, while your head is in a bag, with your eyes closed.




Also, the video contains a little more extrapolated version of the light chart shown in the article. I've attached that below.

Offline djellison

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Re: Opportunity rover updates and discussion
« Reply #30 on: 06/12/2018 01:21 AM »
Using some math, the published Tau value of 10.8, and the info here : https://mars.jpl.nasa.gov/mer/mission/status_opportunityAll.html#sols-5094

The pre-storm number was around 650 Whrs.   The direct illumination is basically gone (it's about 1/50,000th of what it was) and diffuse glow of the sky would allow no more than a couple of tens of Whrs.   

It's basically not possible for the power to go much lower.   

Both Tau, and power, are all time Mars exploration records ( high, and low, respectively)

The good points..... rover was very clean going into this, summer is coming, and the overnight minimum temperatures will be warmer because of the dust.
« Last Edit: 06/12/2018 01:23 AM by djellison »

Offline Blackstar

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Re: Opportunity rover updates and discussion
« Reply #31 on: 06/12/2018 03:15 AM »
I wish people would avoid anthropomorphising machines.


Online ChrisGebhardt

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Re: Opportunity rover updates and discussion
« Reply #32 on: 06/12/2018 12:50 PM »
Is there any reported Wh/Wh impact of - say - last time the weather was good, compared to today?

Clearly, heater demand may have gone down, but charging over the day is impacted more subtly than simply 'good day Wh/tau', as for example, diffuse light plays a bigger part and may extend the charging time a little.


I asked for specifics on this front and have not had my email or phone call returned the JPL contact.

Offline Targeteer

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Re: Opportunity rover updates and discussion
« Reply #33 on: 06/12/2018 09:37 PM »
June 12, 2018
MEDIA ADVISORY M18-093
NASA to Hold Media Teleconference on Martian Dust Storm, Mars Opportunity Rover
Mars
Mars, as seen by Mars Global Surveyor in 2003.
Credits: NASA/JPL-Caltech/MSSS
Full image and caption

NASA will host a media teleconference at 1:30 p.m. EDT Wednesday, June 13, to discuss a massive Martian dust storm affecting operations of the agency’s Opportunity rover and what scientists can learn from the various missions studying this unprecedented event.

The storm is one of the most intense ever observed on the Red Planet. As of June 10, it covered more than 15.8 million square miles (41 million square kilometers) – about the area of North America and Russia combined. It has blocked out so much sunlight, it has effectively turned day into night for Opportunity, which is located near the center of the storm, inside Mars' Perseverance Valley.

Participants in the teleconference will include:

    John Callas, Opportunity project manager at NASA’s Jet Propulsion Laboratory (JPL)
    Rich Zurek, Mars Program Office chief scientist at JPL
    Jim Watzin, director of the Mars Exploration Program at NASA Headquarters
    Dave Lavery, program executive at NASA Headquarters for the Opportunity and Curiosity rovers

To participate, media must email their name and affiliation to Elena Mejia at [email protected] or call 818-393-5467 / 354-5011.

Visuals accompanying the teleconference will be posted at the start of the event at:

https://www.nasa.gov/marsduststormtelecon

Audio of the teleconference will be streamed live at:

https://www.nasa.gov/live

The teleconference andvisuals will be carried live and archived on:

https://youtube.com/nasajpl/live
Best quote heard during an inspection, "I was unaware that I was the only one who was aware."

Offline Nomadd

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Re: Opportunity rover updates and discussion
« Reply #34 on: 06/13/2018 12:17 AM »
 Practical power level from the array will be zero at much higher illumination than this. The theoretical bit they might get isn't usable because it wouldn't be high enough voltage to do anything.
« Last Edit: 06/13/2018 12:19 AM by Nomadd »

Offline hop

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Re: Opportunity rover updates and discussion
« Reply #35 on: 06/13/2018 03:00 AM »
Probable low power fault (edit: telecon is the same as mentioned above): https://www.jpl.nasa.gov/news/news.php?feature=7155

Quote
NASA Mars Exploration Rover Status Report

Updated at 6:30 p.m. PDT on June 12, 2018

NASA engineers attempted to contact the Opportunity rover today but did not hear back from the nearly 15-year old rover. The team is now operating under the assumption that the charge in Opportunity's batteries has dipped below 24 volts and the rover has entered low power fault mode, a condition where all subsystems, except a mission clock, are turned off. The rover's mission clock is programmed to wake the computer so it can check power levels.

If the rover's computer determines that its batteries don't have enough charge, it will again put itself back to sleep. Due to an extreme amount of dust over Perseverance Valley, mission engineers believe it is unlikely the rover has enough sunlight to charge back up for at least the next several days.

The Martian dust storm that has blotted out the sun above Opportunity has continued to intensify. 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.

NASA is holding a news teleconference on Wednesday, June 13, to discuss the storm and the observations of it by various spacecraft. Details at: https://www.jpl.nasa.gov/news/news.php?feature=7158

Hang in there Oppy  :'(
« Last Edit: 06/13/2018 03:01 AM by hop »

Offline Don2

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Re: Opportunity rover updates and discussion
« Reply #36 on: 06/13/2018 06:37 AM »
Poor little rover, slowly freezing to death in the dark and the cold, smothered by the  dust. Now and again it hears a faint shout from Earth, but it no longer has the energy to reply. The cold seeps into its circuits, embrittles its materials and freezes its electrolytes. Sunshine is just a memory, and the memory is fading.  :'(

Offline as58

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Re: Opportunity rover updates and discussion
« Reply #37 on: 06/13/2018 07:47 AM »
How exactly is the "tau value" defined? It's optical depth (at some, probably optical, wavelength), but towards what? Zenith? Maximum Solar elevation? Mean optical depth towards the Sun over a day?

Offline zhangmdev

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Re: Opportunity rover updates and discussion
« Reply #38 on: 06/13/2018 01:20 PM »
How exactly is the "tau value" defined? <snip>

"Several times a sol, the Mars Exploration Rovers take images of the Sun (using a very dark solar filter) to determine the opacity of the atmosphere (a property that is referred to as "tau"). Here, images of the sun taken since sol 1200 of Opportunity's mission have been calibrated to show how dim the Sun appeared through the dust storm. For sols 1236-1242 (July 16-22, 2007), the skies were so dark that Opportunity could not muster enough power to perform its usual tau measurements.Credit: NASA / JPL / Cornell / animation by Emily Lakdawalla "

http://planetary.org/explore/space-topics/space-missions/mer-updates/2007/07-31-mer-update.html

The situation is much worse than it was 11 years ago.

Offline as58

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Re: Opportunity rover updates and discussion
« Reply #39 on: 06/13/2018 01:28 PM »
"Several times a sol, the Mars Exploration Rovers take images of the Sun (using a very dark solar filter) to determine the opacity of the atmosphere (a property that is referred to as "tau"). Here, images of the sun taken since sol 1200 of Opportunity's mission have been calibrated to show how dim the Sun appeared through the dust storm. For sols 1236-1242 (July 16-22, 2007), the skies were so dark that Opportunity could not muster enough power to perform its usual tau measurements.Credit: NASA / JPL / Cornell / animation by Emily Lakdawalla "

Thanks, but that still doesn't say what exactly tau means.

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