EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: Gary350z on February 14, 2019, 02:25:11 am
-
NASA has offically declared Mars Opportunity rover dead on February 13, 2019 after trying to wake it for the last few months. It was designed to last 90 days, but it lasted 15 years and traveled 28 miles.
A quote from the video's comments:
"The last message from Mars Opportunity rover was:
BATTERY VOLTAGE (main) 47.2V (79% nominal voltage, 8% operational time remaining)
BATTERY VOLTAGE (secondary) 41.6V (70% nominal voltage, 4% operational time remaining)
LIGHT SENSOR LEVEL: 0.0 Lumens"
(I don't know if the above three lines are actually true)
The last image the rover sent was of a dark world, cloaked in dust. Jacob Margolis, a science reporter for KPCC in Pasadena, made a poetic translation of the data Opportunity sent out before going silent: "My battery is low and it's getting dark." :'(
https://youtu.be/w2oFtu_KAbI
Edit 2-17-2019: provided the correct source for the above quote.
-
Nooooooooooooooooooooooo! :-BROKE
Lets go to mars and do cardiopulmonary resuscitation on the toddler! :-DMM
-
This was from 2010, when Spirit got stuck, and then lasted another 2 months:
(https://imgs.xkcd.com/comics/spirit.png)
(Original rollover text: "On January 26th, 2274 Mars days into the mission, NASA declared Spirit a 'stationary research station', expected to stay operational for several more months until the dust buildup on its solar panels forces a final shutdown.")
https://xkcd.com/695/
Also, we need to find out who designed this hardware, which outlasted its design lifetime by about 22 and 59 times, respectively!
-
And this is the one from 2015:
(https://imgs.xkcd.com/comics/opportunity.png)
(Original rollover: "We all remember those famous first words spoken by an astronaut on the surface of Mars: "That's one small step fo- HOLY SHIT LOOK OUT IT'S GOT SOME KIND OF DRILL! Get back to the ... [unintelligible] ... [signal lost]"")
https://xkcd.com/1504/
And then this one just now:
(https://imgs.xkcd.com/comics/opportunity_rover.png)
(Original rollover: "Thanks for bringing us along.")
https://xkcd.com/2111/
-
Poor thing :-( ... Luckily it didn't have AI yet, otherwise it'd have planned human vengeance for leaving it there to die :-)
-
No worries, Musk is already warming up his space car engine, he will go and get it for us.
-
A big gust of wind will fix this right up!
Surely someone is keen enough to sneak some telescope time to keep checking ;D
-
A big gust of wind will fix this right up!
Surely someone is keen enough to sneak some telescope time to keep checking ;D
I'm sure there will be an observatory or two that will be monitoring for a "heartbeat" or some kind of carrier signal for years to come when they aren't engaged in other operations.
Actually, I'll ask someone who is in the industry... standby...
-
A big gust of wind will fix this right up!
Surely someone is keen enough to sneak some telescope time to keep checking ;D
This ^ ^ ^
As I understand it, Opportunity has had similar problems in the past where dust has accumulated on the solar panels. If this is just another (possibly extreme) example, a decent enough gust of wind might just clean them off again.
It may be that the curtain has closed on Opportunity - but I'd not be surprised if we had an encore.
-
Interesting idea for newer rovers, perhaps an onboard compressor to blow potential dust off the panels in the event something like this happened again.
-
It's not unknown for spacecraft to come back to life. One of the ham satellites, AO-7 for example, launched in 1974 became unreliable in 1981 when the battery failed short, and not long afterwards it completely fell silent.
In 2002 one of the cells went open, presumably from temporal chemical changes and continual electrical stress from attempted solar charging.
As a result, when in sunlight, the satellite still operates to this day as an analogue voice transponder. There's no on board computer, it's a bunch of CMOS logic controlling it, so it's pretty dumb. When it goes into eclipse, the limited state held in the CMOS logic is forgotten and it's a crap shoot what analogue transponder mode it comes back up in when back in sunlight as a result. But it still works!
-
Interesting idea for newer rovers, perhaps an onboard compressor to blow potential dust off the panels in the event something like this happened again.
Could you not just have a sheet of some kind of exotic plastic on a roll covering the solar panel (imagine a conveyor belt) and as it rotates, built-in brushes dislodge any loose material? That way if it gets dirty, you could just rotate the covering 180 degrees and have a clean bit on top of the panel itself.
-
Reply from my contact...
Obviously, without power, Opportunity is dead for now and it cannot uplink a signal.
However, all the Mars rovers cannot link directly back to Earth or at best very, very weakly. They can only carry small antennae and Mars is rotating just like Earth so they are not always pointing at Earth. That is why NASA placed other satellites into Mars orbit to act as repeaters because they could carry more power and larger high gain antennas.
What this means is that Opportunity is still being listened for by Mars Reconnaissance Orbiter (MRO) which acts as the repeater. The signals from MRO and other missions are received by the 3 identical NASA Deep Space Network (DSN) stations at Tidbinbilla (Canberra), Goldstone (New Mexico) and Madrid in Spain.
Radio telescopes around the globe might be able to receive a signal if it was being sent and they were pointing in the right direction at the time of signal but they do not have the demodulation equipment to understand a signal nor uplink to it. Hence, they don’t do that. It is left exclusively to the DSN which is listening to the repeater orbiters whenever they transmit at predetermined times based upon their own orbit periods.
Hence, say Tidbinbilla hears a signal, it can recommence a command link IF it is felt economically worthwhile. However, mission planning duty cycles no longer contain tasking for Opportunity.
-
Interesting idea for newer rovers, perhaps an onboard compressor to blow potential dust off the panels in the event something like this happened again.
Could you not just have a sheet of some kind of exotic plastic on a roll covering the solar panel (imagine a conveyor belt) and as it rotates, built-in brushes dislodge any loose material? That way if it gets dirty, you could just rotate the covering 180 degrees and have a clean bit on top of the panel itself.
Better off using RTGs, newer rovers are bigger and do more science, they make solar power not very practical .
Even in full sun Spirit and Opportunity had limitations on how much they could do in a day due to power.
Curiosity with its RTG can do much more science.
I do like the idea of solar power though, there's something cool about it.
I considered building a solar powered quadcopter. once, something that can keep itself hovering in full sun. Just because it would be damn cool. The math says it's doable, but it was to be a meter or two across, weigh almost nothing and use raw silicon solar panels that will crack if you look at them wrong. A lot of work for something that will completely destroy itself after the first crash landing.
-
If part of the solar panels of the rover had to be unfolded when the rover was deployed on Mars, couldn't they be lifted again to some degree in order to make the dust fall off on those panels?
"Just shake the wings and fly again"
-
If Opportunity comes back to life, I'm sure NASA will proudly continue tasking it with something. Even if there isn't anything useful that it could do, the prestige of running a rover for more than a decade is enough reason.
-
<sarcasm>
And besides, it's all done in a hollywood studio anyway, so it isn't like it would cost a lot. If the Karsashian show is so good at keeping the American public sedated, a little help from the Opportunity drama woldn't hurt :-DD
</sarcasm>
-
If part of the solar panels of the rover had to be unfolded when the rover was deployed on Mars, couldn't they be lifted again to some degree in order to make the dust fall off on those panels?
"Just shake the wings and fly again"
Unfortunately, such mechanisms are usually designed to operate in one direction - to deploy the solar cells which then stay deployed for the duration of the mission. There would have to be a pretty compelling argument to make those mechanisms bidirectional as this would add complexity, weight and an increase in the number of potential failure modes, not to mention cost. While designs of such craft are given as many safeguards, redundancy, backups, etc. as possible, there has to be a line drawn somewhere.
Considering the time Opportunity has logged over and above its original mission, I'd say the design was eminently successful.
-
Some Opportunity hardware porn
The radiation hardened PowerPC 750 CPU boards cost $200K each
(https://www.extremetech.com/wp-content/uploads/2012/10/rad750-bae-systems.jpg)
(https://external-preview.redd.it/Ek85jWTfvJwkem6upAF2CyVlrnb73IVeTaeau2lKhZo.jpg?auto=webp&s=b3a1fbdd28d245fdc9c035662c409f97f7baa284)
(https://www.nasa.gov/images/content/682929main_SAM_exposed_annotated_Mahaffy.jpg)
-
The radiation hardened PowerPC 750 CPU boards cost $200K each
I believe Spirit and Opportunity use the 20Mhz BAE RAD6000.
Curiosity/2020 Rover and several others use the 200 MHz BAE Power 750 with 256 MB of RAM, 2GB flash, 256KB of ROM. It has been mentioned several times this CPU power has been a limiting factor for them and a newer much faster system is in the works. :-+
-
that bodge on the lt1764a :o
-
https://www.youtube.com/watch?v=1Ll-VHYxWXU (https://www.youtube.com/watch?v=1Ll-VHYxWXU)
:-+
-
Not sure how much of a window they have for Opportunity to revive itself if the solar panels did get somehow cleaned. If it is out of power for too long and it is too cold then the electronics and batteries are damaged permanently. It has radioisotope heaters to keep the internals warm but those aren't sufficient by themselves so it also has electrical heaters.
-
Hardware Porn indeed!
The only recognizable device from the photo is the LT1761 a Low Noise, LDO Micropower Regulator from Linear Tech.
The datasheet is too large to attach, but here is the webpage: https://www.analog.com/en/products/lt1761.html (https://www.analog.com/en/products/lt1761.html)
What I find surprising is that it is plastic encapsulated, as there are several other ICs as well. I would guessed that everything would use either ceramic or frit-sealed metal packages.
Of course, this must be a special device which has been tested and burned-in as hell!
Edit:
OOOOPS! It is a LT1764
-
Not sure how much of a window they have for Opportunity to revive itself if the solar panels did get somehow cleaned. If it is out of power for too long and it is too cold then the electronics and batteries are damaged permanently. It has radioisotope heaters to keep the internals warm but those aren't sufficient by themselves so it also has electrical heaters.
Strange things do happen.
Amsat Oscar 7 was launched in 1974, & enthusiastically used by the Amateur Radio community, till it ceased operating in 1981.
It then became a "fond memory", until June 21, 2002, when its beacon was heard by Amateurs.
It appears that the original fault was a shorted battery.
Over time, the battery became open circuit, allowing the satellite to work when the solar cells were fully illuminated.
It has been used, whenever that is happening, ever since.
-
Interesting idea for newer rovers, perhaps an onboard compressor to blow potential dust off the panels in the event something like this happened again.
Could you not just have a sheet of some kind of exotic plastic on a roll covering the solar panel (imagine a conveyor belt) and as it rotates, built-in brushes dislodge any loose material? That way if it gets dirty, you could just rotate the covering 180 degrees and have a clean bit on top of the panel itself.
They evaluated various solutions including blowing air, wipers, and removable plastic film but the extra complexity and weight was judged to be too much. Like roof mounted solar panels in many applications, it would be better to just include excess capacity.
What I find surprising is that it is plastic encapsulated, as there are several other ICs as well. I would guessed that everything would use either ceramic or frit-sealed metal packages.
Plastic packages got better and once ceramic package production volumes dropped, reliability dropped also. LT has not made ceramic TO-220s in a long time if they ever did. Extra screening is not that big a deal.
Personally I have used commercial plastic packaged parts down to liquid nitrogen temperatures without problems. It is kind of eerie when everything still works but some linear ICs have startup problems at cold temperatures.
-
Hardware Porn indeed!
The only recognizable device from the photo is the LT1761 a Low Noise, LDO Micropower Regulator from Linear Tech.
The datasheet is too large to attach, but here is the webpage: https://www.analog.com/en/products/lt1761.html (https://www.analog.com/en/products/lt1761.html)
What I find surprising is that it is plastic encapsulated, as there are several other ICs as well. I would guessed that everything would use either ceramic or frit-sealed metal packages.
Of course, this must be a special device which has been tested and burned-in as hell!
Edit:
OOOOPS! It is a LT1764
That's exactly what I noticed too, that mix of plastic and more durable encapsulations even on the same board. It may be a matter of using the best you can get.
-
They evaluated various solutions including blowing air, wipers, and removable plastic film but the extra complexity and weight was judged to be too much. Like roof mounted solar panels in many applications, it would be better to just include excess capacity.
Plastic packages got better and once ceramic package production volumes dropped, reliability dropped also. LT has not made ceramic TO-220s in a long time if they ever did. Extra screening is not that big a deal.
Personally I have used commercial plastic packaged parts down to liquid nitrogen temperatures without problems. It is kind of eerie when everything still works but some linear ICs have startup problems at cold temperatures.
These parts are probably used in a pressurised hull, but outgassing can be a huge problem in space. You need very few particles to contaminate sensors and other sensitive surfaces.
-
If part of the solar panels of the rover had to be unfolded when the rover was deployed on Mars, couldn't they be lifted again to some degree in order to make the dust fall off on those panels?
No. Usually solar panels are spring loaded. When they need to deploy a cord holding the panels folded together is cut using a thermal knife and the springs do the rest.
-
That's exactly what I noticed too, that mix of plastic and more durable encapsulations even on the same board. It may be a matter of using the best you can get.
There might also be contribution from the differences in how digital and linear ICs are packaged in plastic packages. Linear ICs use an encapsulation inside the plastic package to isolate the silicon die from the package. Otherwise strain induced in the silicon die ruins transistor matching. I expect that plastic packaged digital ICs would be less reliable over wide temperature swings making ceramic packages desirable although they got away with plastic for the memory ICs.
There is an interview with I think Bob Dobkin where he relates a story of a manager complaining that linear ICs cannot use the cheaper packaging process of digital ICs and once where someone changed it and ruined production of linear ICs until they fixed it.
-
cellphone vibration motor to shake the dust off
-
cellphone vibration motor to shake the dust off
Panels are fixed horizontal.
-
Last images uploaded from Opportunity (includes an impressive high resolution interactive panorama): https://www.jpl.nasa.gov/news/news.php?feature=7348 (https://www.jpl.nasa.gov/news/news.php?feature=7348)