Author Topic: Opportunity rover updates and discussion  (Read 36749 times)

Online ccdengr

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Re: Opportunity rover updates and discussion
« Reply #40 on: 06/13/2018 02:16 PM »


Thanks, but that still doesn't say what exactly tau means.
https://en.wikipedia.org/wiki/Optical_depth under "atmospheric sciences"

Offline zhangmdev

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Re: Opportunity rover updates and discussion
« Reply #41 on: 06/13/2018 02:45 PM »
My understanding is, to estimate how much light is attenuated after passing through the media, i.e. the Mars atmosphere, need to estimate the transmittance of the media based on the brightness of the Sun in those tau images, calibrated against its brightness in a clear sky, of the same solar elevation angle.

https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law

Offline as58

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Re: Opportunity rover updates and discussion
« Reply #42 on: 06/13/2018 02:57 PM »
https://en.wikipedia.org/wiki/Optical_depth under "atmospheric sciences"

Thanks. So apparently in atmospheric (and I guess also planetary) science tau, without further qualification, means optical depth towards the zenith.

Online redliox

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Re: Opportunity rover updates and discussion
« Reply #43 on: 06/13/2018 03:21 PM »
"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.

Fingers crossed for Opportunity, but something this large, if anything, sadly might be the final nail in the coffin.  We'll only know for sure after a few days.
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Offline Ilikeboosterrockets

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Re: Opportunity rover updates and discussion
« Reply #44 on: 06/13/2018 04:08 PM »

Offline Nomadd

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Re: Opportunity rover updates and discussion
« Reply #45 on: 06/13/2018 04:50 PM »
 This would be one helluva last series of photos.
http://bgr.com/2018/06/13/opportunity-dust-storm-mars-nasa-photos/
« Last Edit: 06/13/2018 04:50 PM by Nomadd »

Online Orbiter

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Re: Opportunity rover updates and discussion
« Reply #46 on: 06/13/2018 04:53 PM »
This dust storm is so intense even amateurs can easily spot it in a small telescope. I've been watching it with my 8" dobsonian and Syrtis major, one of the more prominent features on Mars, is almost completely obscured. This is turning into a global event.
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Offline 1

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Re: Opportunity rover updates and discussion
« Reply #47 on: 06/13/2018 05:33 PM »
JPL news conference going live.


Offline Chris Bergin

Re: Opportunity rover updates and discussion
« Reply #48 on: 06/13/2018 05:48 PM »
How the Mars dust storm caught Opportunity right in the middle of it.

Offline Chris Bergin

Re: Opportunity rover updates and discussion
« Reply #49 on: 06/13/2018 05:57 PM »
Sounds positive. Won't breach the coldest allowable temperatures. Won't be "buried alive" (reporter question). Can hunker down for a long time and recharge when the sky clears. The concern is how long they can continue in low power (and then to wake up/communicate correctly).

Offline Chris Bergin

Re: Opportunity rover updates and discussion
« Reply #50 on: 06/13/2018 06:12 PM »
"We're very concerned. The team has a very tight bond with the Rover. It's like a loved one (and said an old grandma, due to the age) in the hospital with a coma."

Offline Ilikeboosterrockets

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Re: Opportunity rover updates and discussion
« Reply #51 on: 06/13/2018 06:29 PM »
Sounds positive. Won't breach the coldest allowable temperatures. Won't be "buried alive" (reporter question). Can hunker down for a long time and recharge when the sky clears. The concern is how long they can continue in low power (and then to wake up/communicate correctly).

"Won't breach the coldest allowable temperatures" as long as the heaters stay active, correct? Or can the rover survive without the heaters? And do we know if the rover has enough reserve power to keep the heaters active for weeks/months?

Offline 1

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Re: Opportunity rover updates and discussion
« Reply #52 on: 06/13/2018 06:32 PM »
Sounds positive. Won't breach the coldest allowable temperatures. Won't be "buried alive" (reporter question). Can hunker down for a long time and recharge when the sky clears. The concern is how long they can continue in low power (and then to wake up/communicate correctly).

"Won't breach the coldest allowable temperatures" as long as the heaters stay active, correct? Or can the rover survive without the heaters? And do we know if the rover has enough reserve power to keep the heaters active for weeks/months?

Mentioned a few times, but since ambient temperatures aren't expected to drop below minimum, primary concern is providing sufficient power to the mission clock. All electronics, including heaters, can be deactivated. Further loss of power will cause a 'clock fault' that will cause the rover to lose track of what time it is and will cause erratic behavior in terms in communications. Team is prepared for that possibility and will hopefully be able to restore proper behavior if that happens.

Offline Yellowstone10

Re: Opportunity rover updates and discussion
« Reply #53 on: 06/13/2018 07:05 PM »
"Won't breach the coldest allowable temperatures" as long as the heaters stay active, correct? Or can the rover survive without the heaters? And do we know if the rover has enough reserve power to keep the heaters active for weeks/months?

The electric heaters are off when the rover is in a low-power fault, but it also has 8 radioisotope heater units that put out about 1 watt each. In today's briefing, they said that between those heaters and the ambient temperature, the rover is expected to stabilize at -36 °C. It's designed to operate down to -40 °C, so it should be good.

Online FutureSpaceTourist

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Re: Opportunity rover updates and discussion
« Reply #54 on: 06/13/2018 07:20 PM »
Great twitter thread capturing lots of key points from press conference:

https://twitter.com/elakdawalla/status/1006952540234059776

Thread is too long to capture all here.

Scary pic of the increasing atmospheric opacity attached.

2nd pic for:

Quote
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.

https://twitter.com/elakdawalla/status/1006955982969135104

Quote
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

https://twitter.com/elakdawalla/status/1006957012280700938

Offline Star One

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Opportunity rover updates and discussion
« Reply #55 on: 06/13/2018 07:58 PM »
Quote
Briefing’s over. Key takeaway is that, despite some concerns, the Opportunity project team is optimistic that the rover will make it through the dust storm.

https://mobile.twitter.com/jeff_foust/status/1006967973880451081

Quote
NASA doesn’t expect storm to affect Curiosity; only in worst-case scenario would there be any concerns about dust being deposited on optics.

https://mobile.twitter.com/jeff_foust/status/1006962856426917889
« Last Edit: 06/13/2018 08:01 PM by Star One »

Offline theinternetftw

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Re: Opportunity rover updates and discussion
« Reply #56 on: 06/13/2018 08:01 PM »
Here are the last two slides that were in the presentation, one of Curiosity's observation of the planet-wide storm, and another of the storm spreading animation.

edit: clarifying what the first slide is.
« Last Edit: 06/13/2018 08:59 PM by theinternetftw »

Offline Don2

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Re: Opportunity rover updates and discussion
« Reply #57 on: 06/13/2018 11:27 PM »
The dust storm is good news for some: From Jan 2018 article:

Quote
Some Mars experts are eager and optimistic for a dust storm this year to grow so grand it darkens skies around the entire Red Planet.

This biggest type of phenomenon in the environment of modern Mars could be examined as never before possible, using the combination of spacecraft now at Mars.

A study published this week based on observations by NASA's Mars Reconnaissance Orbiter (MRO) during the most recent Martian global dust storm -- in 2007 -- suggests such storms play a role in the ongoing process of gas escaping from the top of Mars' atmosphere. That process long ago transformed wetter, warmer ancient Mars into today's arid, frozen planet.

https://www.nasa.gov/feature/jpl/dust-storms-linked-to-gas-escape-from-mars-atmosphere

On another topic, the best positioned camera to monitor this dust storm is probably the Indian one. Is there any chance we might see anything from them?
« Last Edit: 06/13/2018 11:29 PM by Don2 »

Online DaveS

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Re: Opportunity rover updates and discussion
« Reply #58 on: 08/16/2018 09:53 AM »
There's good news today! DSS-34 has detected a strong carrier signal from Opportunity! Active commanding is currently in progress.

Edit: Based on the frequency and data rate of the initial AOS, this was from the rover's steerable high gain antenna (6.00 Mb/s, 8.44 GHz).
« Last Edit: 08/16/2018 10:06 AM by DaveS »
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Online DaveS

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Re: Opportunity rover updates and discussion
« Reply #59 on: 08/16/2018 10:23 AM »
The Opportunity downlink signal disappeared for a while indicating most likely that the playback of stored data has been completed. This is an indication that the rover is following a preset schedule of commands of what do to when ever it recovers from a low-power fault.

The signal has now returned some 18 minutes after active commanding began which shows that the rover is alive and can be commanded from the ground.
"For Sardines, space is no problem!"
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