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‘My power’s low’: NASA’s Insight Mars lander prepares to sign off

theguardian.com

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Re: ‘My power’s low’: NASA’s Insight Mars lander prepares to sign off

#111

Post by matrix12 »

penguin_booze wrote: post #58
thathndude wrote: post #12

I know these are inanimate objects and we shouldn’t humanize them. Blame XKCD, I suppose. But I feel a connection to these robots, and I pray that one day we can go to Mars and erect them a place of honor or bring them “home” to a Smithsonian. They are a testament to the best of our space programs and the men and women who work in them. It’s amazing how well some of these machines overperformed.

I was suddenly reminded of Alex the African Gray Parrot's dying words: "You Be Good, See You Tomorrow. I Love You". https://www.wired.com/2007/09/super-smart-par/

Not Dying words. Merely the same thing he said every day when put in his cage. Died in his sleep.

Re: ‘My power’s low’: NASA’s Insight Mars lander prepares to sign off

#113

Post by armatav »

Avshalom wrote: post #43
thathndude wrote: post #12

I know these are inanimate objects and we shouldn’t humanize them. Blame XKCD, I suppose. But I feel a connection to these robots, and I pray that one day we can go to Mars and erect them a place of honor or bring them “home” to a Smithsonian. They are a testament to the best of our space programs and the men and women who work in them. It’s amazing how well some of these machines overperformed.

>>we shouldn’t humanize them Nah, our ability and willingness to develop empathy and emotional connections to dogs, bugs, robots, small rocks... It's one of our best traits.

Yup - big part of what makes us human

Re: ‘My power’s low’: NASA’s Insight Mars lander prepares to sign off

#114

Post by Retric »

m4rtink wrote: post #80
Retric wrote: post #55

Earlier quoted context omitted.

Most critically, other components are also failing so you don’t get that much more lifespan with unlimited power. A brush doesn’t work well in a zero moisture environment. The dust is horrifically abrasive and brushing it along the panels would cause damage. The added weight would have to be compensated for.

Well, the MERs lasted quite a bit longer & were moving systems. A bit of a shame a static lander can't beat them. :P

Insight isn’t dead just hibernating which both MERs did several times.

If Insight dies then Spirit will have lasted 50% longer and opportunity significantly longer, but both rovers lost quite a bit of functionality over time. So, the difference isn’t as stark as you might assume when you consider how much time rovers spent with reduced power or hibernating, stuck, etc.

Re: ‘My power’s low’: NASA’s Insight Mars lander prepares to sign off

#115

Post by mturmon »

hn_throwaway_99 wrote: post #84
logicallee wrote: post #32

Earlier quoted context omitted.

After reading your note "why it's not possible for the solar panels to be self cleaned" I clicked through and as I clicked I was thinking "okay so obviously it is possible for the solar panels to self-clean. prove me wrong." I mean how hard could it be? No way is that an "impossible" task. I went out of it thinking, "yep, look at these excuses we are making for the state of robotics." - the quote is: "A system like t…

This reply completely misses the point. All missions have an expected lifespan. The reason why they didn't use some sort of cleaning system is simply because it wasn't needed . The lander gathered all the data it was expected to, and then some. Why add complexity if it isn't useful?

^-- This is the answer: this capability wasn't needed to fulfill science objectives. End of story.

To add context: InSight was proposed to a cost-capped, competitive NASA program. Within competed programs, you can't spend money on nice-to-have's. You have to come in under a cost cap, while demonstrating you will achieve science objectives. Period.

The science objectives are carefully time-bound by a very knowledgeable science team, and from those science requirements, all the engineering requirements, including lifetimes, are derived. InSight didn't need more than one Mars year for the science, so that's that.

There were 2 instruments. In the case of the heat probe, they needed to observe at least one full annual heating cycle. For the seismograph, I think they had an approximate event rate and they needed to capture X number of events of a given magnitude to get insight (heh!) into the subsurface structure.

Here's a description of how this works in general, from someone who was involved in InSight formulation and who is in the leadership of mission formulation at JPL:

https://science.nasa.gov/science-red/s3fs-public/atoms/files...

The whole presentation is great: the first introductory slides, some InSight examples, and the last 3 slides in particular give background on some of my claims above.

The person who (with the PI, Bruce Banerdt) led the InSight "requirements trace" is Peg Frerking (https://scholar.google.com/citations?user=t6XZBAIAAAAJ&hl=en), who is now a JPL fellow in part because of her work in adding engineering rigor to the formulation process.

As this thread shows, it's very easy for clever engineers to add on nice-to-have's that are not required to meet science objectives. That's how you get overruns.

Here's another recent HN reference point on capabilities that don't contribute to a great product: https://news.ycombinator.com/item?id=34032672 [Steve Jobs Insult Response]

Re: ‘My power’s low’: NASA’s Insight Mars lander prepares to sign off

#116

Post by kitd »

photochemsyn wrote: post #72
simonswords82 wrote: post #19

Interesting thread on why it's not possible for the solar panels to be self cleaned: https://twitter.com/NASAInSight/status/1590736220199735296?c...

Given the success of the helicopter drone (Ingenuity) on Mars, I wonder if that's an option for cleaning solar panels - i.e. put a simple rotating brush/fan system on the drone, keep it in a port on the main lander, and every once in a while, launch it and have it land on the solar panels, where it does a roomba routine. Since drones already expand the abilities of a lander, i.e. exploring the immediate area and coll…

Or have the drone fly low over the panels, making use of the down-draught.

Re: ‘My power’s low’: NASA’s Insight Mars lander prepares to sign off

#117

Post by Zancarius »

JoeAltmaier wrote: post #109
simonswords82 wrote: post #19

Interesting thread on why it's not possible for the solar panels to be self cleaned: https://twitter.com/NASAInSight/status/1590736220199735296?c...

Cant just use a pad on the arm to rub away at them?

What happens when the pad gets choked out with dust?

Re: ‘My power’s low’: NASA’s Insight Mars lander prepares to sign off

#119

Post by idlewords »

prettyStandard wrote: post #2

I'm confused on why the end state for all these rovers is to loose power because of dust on the solar cells. They did such a good job engineering these things to survive the trip and the conditions in general, but they can't give them "windshield wipers for dust"? Seems like with that minor upgrade they could have much longer lifespan. Can someone enlighten me?

They gave Curiosity and Perserverance a plutonium power source to avoid this issue.

My experience with "why don't they just X" for space stuff is that there's almost always a technical paper on it. This looks like a comprehensive review of different approaches to cleaning solar panels on rovers:

"Cleaning Mechanisms for Solar Panels of Rovers and Other Extraterrestrial Unmanned Vehicles" https://doi.org/10.2514/6.2019-3452

Re: ‘My power’s low’: NASA’s Insight Mars lander prepares to sign off

#120

Post by jws »

wazoox wrote: post #42
simonswords82 wrote: post #19

Interesting thread on why it's not possible for the solar panels to be self cleaned: https://twitter.com/NASAInSight/status/1590736220199735296?c...

It's pretty amazing to think it still works with the panels as covered in dust as they are in the last frame!

Solar panel output is remarkably resilient to visible dirt. I have an installation on a seagull rookery. As you can imagine things get thoroughly “whitewashed”, especially since the top edge of the angled array is prime “standing around squawking and crapping” space. They can be covered to the point that there isn’t a clean spot the size of your fist anywhere on them and they will still be putting out 75% of their rated power.

I suspect it has something to do with the non-linear response of the human eye. You don’t have to reflect a lot of light to be perceived as significantly lighter than black, so diverting 25% of the light from the panel to reflected light makes the panel look quite light.

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