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NASA's Perseverance rover sends stunning images

bbc.com

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Re: NASA's Perseverance rover sends stunning images

#41

Post by Robotbeat »

walrus01 wrote: post #30
Robotbeat wrote: post #24

Earlier quoted context omitted.

They use the same kind of compression as the last mission. JP2, I believe. https://en.wikipedia.org/wiki/JPEG_2000 I'm not sure that data compression has progressed that much since Curiosity in 2012 or Insight in 2018. There have been some formats that have improved compression at the expense of large amounts of memory or processing power, but neither of those are abundant on a rad-hardened processor. Neither is elec…

One of the obvious constraints is that for science reasons they transmit each image in a lossless format, so we're up against the limits of what a lossless image compressor can do. If there were a future mission's requirement to send back lossy images first, and CPU power was significant, something like AVIF or JPEG-XL would likely be a candidate. https://netflixtechblog.com/avif-for-next-generation-image-c... ICER a…

Thanks for that. Yes, they do both lossless and lossy compression. I think sometimes they may send the lossy image (especially if for a navigation or engineering camera) and request a lossless image if there's something particularly interesting.

Re: NASA's Perseverance rover sends stunning images

#42

Post by sp332 »

jcims wrote: post #27
milofeynman wrote: post #8

How close was the rover to its intended landing spot?

Nailed it - https://www.jpl.nasa.gov/images/avoiding-hazards-at-jezero-c... (A little more complicated than that of course. If I understand correctly, anything in blue was a candidate landing spot that it was free to select from. I'm pretty sure the header image is an artistic crop :) )

It was almost that good. It had a five-mile-wide ellipse to search, and found a spot close to the middle. https://science.sciencemag.org/content/sci/371/6532/870/F1.l... If you have a Science magazine subscription, the image is from this article: https://science.sciencemag.org/content/371/6532/870?rss=1/sh...

Re: NASA's Perseverance rover sends stunning images

#43

Post by rsj_hn »

jcims wrote: post #39
moltar wrote: post #35

Earlier quoted context omitted.

I admire your efforts to clean. But unfortunately it’s pointless. There are entire million and billion population countries that treat oceans as waste baskets, simply because they don’t know better. I’ve talked to fishermen in rural Thailand and they don’t have waste collection. So they take their trash every day and just dump it in the middle of the ocean somewhere. They didn’t understand why that was a problem when…

My imagination has a pretty big range for 'rural Thailand', do they have a safe way to dispose of it inland? Subsistence folks, to the extent that it might apply here, get a pass from me.

The issue is that 90% of the plastic in the ocean is dumped from 10 rivers in Asia and Africa where the waste disposal system consists of driving a truck up to a river and dumping the trash in. Of the remaining 10%, it comes from Latin American nations that do the same thing.

Meanwhile western people see these masses of trash and plastic in the ocean and conclude the rational response is to ban straws in the western nations that do have effective waste disposal systems that don't consist of transporting said waste to the ocean and dumping it.

So the question is whether the outrage about ocean pollution is harnessed towards effectively addressing the problem or whether it is dissipated in the heat of pointless kabuki rituals that we do to absolve ourselves of guilt, even as the trash in the oceans piles up every time someone in the third world throws something away.

Re: NASA's Perseverance rover sends stunning images

#44

Post by 11thEarlOfMar »

Stupid question, but where is Perseverance's energy source?

Answer: Plutonium

It powers a Multi-Mission Radioisotope Thermoelectric Generator.

The plutonium decays at a few % per year, so that means it should be able to bring Elon a sandwich when he lands.

https://mars.nasa.gov/mars2020/spacecraft/rover/electrical-p...

Re: NASA's Perseverance rover sends stunning images

#45

Post by Cogito »

milofeynman wrote: post #8

How close was the rover to its intended landing spot?

It landed quite close to the centre of its landing ellipse, which was significantly smaller than the landing zones of previous missions.

Perhaps most impressive is the success of the terrain relative navigation. During descent a specific landing site was chosen, after going through atmospheric entry. That site had to be reachable based on where they ended up after entry, needed to be safe to land in, and should land as close as reasonable to scientifically interesting sites. The system chose a pixel from the initial images taken during descent, and the final landing was within 5m of that spot.

Re: NASA's Perseverance rover sends stunning images

#47

Post by azernik »

rsj_hn wrote: post #32
uomo wrote: post #11

Earlier quoted context omitted.

https://mars.nasa.gov/mars2020/multimedia/raw-images/ Would be the best place to get images/videos from Perseverance.

I want to see that little helicopter fly! I scoured the site and as yet can't find any images of it, when I thought they were going to take mutual selfies -- heli of the rover and vice versa.

The helicopter hasn't flown yet - they put it down on the ground, and they're going to run it through a lot of remote checks before flying it. IIRC it's gonna be a month or two before first flight.

Re: NASA's Perseverance rover sends stunning images

#48

Post by vlovich123 »

jcims wrote: post #39
moltar wrote: post #35

Earlier quoted context omitted.

I admire your efforts to clean. But unfortunately it’s pointless. There are entire million and billion population countries that treat oceans as waste baskets, simply because they don’t know better. I’ve talked to fishermen in rural Thailand and they don’t have waste collection. So they take their trash every day and just dump it in the middle of the ocean somewhere. They didn’t understand why that was a problem when…

My imagination has a pretty big range for 'rural Thailand', do they have a safe way to dispose of it inland? Subsistence folks, to the extent that it might apply here, get a pass from me.

What’s the waste stream looking like? Like can we trace how this trash originates and why it’s not ending up where it should? If poor areas with weak government services are the problem, then that’s a problem, no?

Re: NASA's Perseverance rover sends stunning images

#49

Post by asdff »

hanniabu wrote: post #29
soheil wrote: post #18

Nasa's image gallery UI is such a pain to use, I wish someone would upload these into a more user friendly photo viewer tool.

What's difficult about it?

Multiple clicks to get to the full resolution image. 50 thumbnails able to be viewed at a time, many uninteresting to lay people (solid gray screen, dozens of repeated images of of a portion of the rover itself, etc), for the monumental task of sifting through the 6407 images the rover has transmitted so far in mere days. Wholly unusable in a few months I imagine.

Re: NASA's Perseverance rover sends stunning images

#50

Post by AnimalMuppet »

perardi wrote: post #40
medium_burrito wrote: post #22

Earlier quoted context omitted.

You triggered the fuck out of me. The saving grace of the Joint Strike Jobs program is that maybe 1% of the people learned what to do next time.

Yes yes, I know, it’s trite to point out that boondoggle of a project. Except…NASA apparently spent all of $80 million on a helicopter that will work on Mars. One has to wonder what the military-industrial complex could accomplish with a bit of financial discipline and oversight.

The NASA helicopter had to work at all on Mars. It's amazing that they succeeded. But it didn't have to survive in an environment with Martian SAM sites, or even rifle fire from the ground.

That is, the military requirements are much more intense than we often realize.

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