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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

#21

Post by theandrewbailey »

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?

Spirit and Opportunity lasted for much longer (6 and 14 years, respectively), aided by periodic winds that blew dust off the solar panels. It appears that Insight's location doesn't receive many of these compared to others.

https://www.sciencealert.com/nasa-s-insight-lander-enters-hi...

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

#22

Post by bluGill »

danw1979 wrote: post #9
jacquesm wrote: post #4

Earlier quoted context omitted.

(1) they were intended to last for three months and (2) dust is extremely static and there is no really good way there to get rid of this static charge, (3) dust is pretty sharp ('abrasive') and will scratch the surface of the cells if removed mechanically.

Regarding (1), almost all of these Mars robots seem to do useful science well beyond the end of the stated mission, I think the OP was suggesting that maybe it’s time we start trying out solutions for much longer duration missions ? (2) - could it be possible to introduce an oppositely static charged layer on the panel surface to repel dust to stop it settling in the first place ?

Every part needs to last 3 months. If even one part breaks after 2 months the whole thing failed. Each part increases the odds that one will break after 2 months. The only way to work around this is to design each part to last for 5 years, that way the odds are high that all parts survive for the required 3 months. It also means that odds are reasonable the rover will work for much longer than 3 months, and in many cases you can operate in a degraded state for a even longer.

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

#23

Post by bluGill »

hawski wrote: post #6
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?

I am sure it comes down to economics really, but I do wonder now about a mission in far future, that would clean solar panels of all those older missions to make them work again. For shits and giggles I guess.

It might be fun to try, but realistically, without heat, thermo issues will ensure that even if you did this the rovers wouldn't work anymore.

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

#24

Post by brnt »

bamboozled wrote: post #3
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?

Windshield wipers add weight and complexity but more importantly add to the budget. These things are designed only to serve the mission. This rover was designed to last 1 year and went for 4 so it’s a pretty good result. Some good discussion here [1] on Astronomy Cast regarding this topic and potential solutions NASA is working on. Such as an electrostatic dust blaster. 1. https://podcasts.apple.com/vu/podcast/astron…

They add weight, but also may extend the mission, meaning for science for buck. NASA rovers outlast their no doubt conservatively estimated life expectancy consistently.

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

#25

Post by bluGill »

user3939382 wrote: post #17

As a programmer my first thought reading this was: If I was designing a program to send me back a message and it was super critical I received it, I wouldn't put any quotes or non-alphanumerics in the message. Even if my string handling checks out, if the stakes are sufficiently high, I don't trust em!

If I was designing such a message I'd make sure there is a lot of redundancy in the message so even if I only received part of it I could figure out what it was. Adding quotes and other non-alphanumerics can add more clues that make the message unique enough to identify it even when significant amounts of the data are lost in transmission.

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

#26

Post by intrasight »

jcims wrote: post #16
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 fully expect to see one of the rovers to be at the Smithsonian before I die, and I’m almost 50 sooo chop chop!

But I expect that Musk will keep it in his private collection ;)

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

#27

Post by prettyStandard »

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...

They would rather contribute that cost&weight&complexity to just more solar cells. Got it.

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

#28

Post by bnralt »

danw1979 wrote: post #9
jacquesm wrote: post #4

Earlier quoted context omitted.

(1) they were intended to last for three months and (2) dust is extremely static and there is no really good way there to get rid of this static charge, (3) dust is pretty sharp ('abrasive') and will scratch the surface of the cells if removed mechanically.

Regarding (1), almost all of these Mars robots seem to do useful science well beyond the end of the stated mission, I think the OP was suggesting that maybe it’s time we start trying out solutions for much longer duration missions ? (2) - could it be possible to introduce an oppositely static charged layer on the panel surface to repel dust to stop it settling in the first place ?

> almost all of these Mars robots seem to do useful science well beyond the end of the stated mission

How are we defining "useful science" here? They all do some kind of scientific investigations, but it's hard to say if it's useful or not. If you look at coverage or discussions about the lander (including here), people get very excited about the landings, and somewhat excited about the pictures. The science almost never gets discussed. Even when NASA tries to hype it up, it seems the most important stuff they have is continually telling us they found Mars has some water and used to be wet, and that there's the possibility there once was life on Mars.

People seem enamored with the idea that we're sending things to Mars and doing "something." But there doesn't seem to be a lot of concern about what that "something" actually is.

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

#29

Post by wongarsu »

brnt wrote: post #24
bamboozled wrote: post #3

Earlier quoted context omitted.

Windshield wipers add weight and complexity but more importantly add to the budget. These things are designed only to serve the mission. This rover was designed to last 1 year and went for 4 so it’s a pretty good result. Some good discussion here [1] on Astronomy Cast regarding this topic and potential solutions NASA is working on. Such as an electrostatic dust blaster. 1. https://podcasts.apple.com/vu/podcast/astron…

They add weight, but also may extend the mission, meaning for science for buck. NASA rovers outlast their no doubt conservatively estimated life expectancy consistently.

Well, you give a mission plan of one year, and design a rover to fit that plan. And because you don't want to fail, you engineer everything to have a tiny failure rate in the first year. That also makes the systems likely to work for many more years, but that's just a side effect. You have only explicitly designed and spent money on that first year. Taking funding from that first year to add a system that only becomes useful in year three is a completely different matter, and likely much harder to greenlight.

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

#30

Post by thereddaikon »

bamboozled wrote: post #3
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?

Windshield wipers add weight and complexity but more importantly add to the budget. These things are designed only to serve the mission. This rover was designed to last 1 year and went for 4 so it’s a pretty good result. Some good discussion here [1] on Astronomy Cast regarding this topic and potential solutions NASA is working on. Such as an electrostatic dust blaster. 1. https://podcasts.apple.com/vu/podcast/astron…

Seems a bit shortsighted to me. Given that if they avoid a catastrophic failure before landing these things seems to consistently last beyond the originally planned mission, they should be building them with mission extensions in mind.

Not putting all your eggs in one basket of course. Shit happens and probes are still lost even today. But a simple device to remove dust such as a vibration function, a small blower fan or something else seems to be a major value add.

Even if it costs $1 million extra to do, it costs far more to build the rover and send it there so you are still saving money.

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