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

theguardian.com

51–60 of 187 posts

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

#51

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

If only there was a simple mechanism, maybe a four bar linkage, with trillions of cycles of testing... it would have to be light weight and include some form of brush or wiper and function with significant forces applied, similar to wind from a moving vehicle... I guess the downside of having JPL in SoCal is that none of the engineers are familiar with windshield wipers.

"A system like that would have added cost, mass, and complexity. The simplest, most cost-effective way to meet my goals was to bring solar panels big enough to power my whole mission – which they did (and then some!)."

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

#52

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

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…

You did it, you solved RObotics! Someone get this guy a Nobel Prize!! JPL Engineers are no match for his staggering intellect!

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

#54

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?

Same reason the rockets NASA uses are not reusable. It’s not part of the mission.

Yes, it’s short sighted but unfortunately a result of extreme budget constraints.

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

#55

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

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…

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.

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

#56
post #24

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.

Every component runs into issues, look at how many rover’s wheels had issues before the panels failed.

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

#57

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?

Oliver Wendell Holmes can (http://holyjoe.org/poetry/holmes1.htm):

The Deacon’s Masterpiece or, the Wonderful "One-hoss Shay": A Logical Story

Have you heard of the wonderful one-hoss shay,

That was built in such a logical way

It ran a hundred years to a day,

And then, of a sudden, it — ah, but stay,

I’ll tell you what happened without delay,

Scaring the parson into fits,

Frightening people out of their wits, —

Have you ever heard of that, I say?

Seventeen hundred and fifty-five.

Georgius Secundus was then alive, —

Snuffy old drone from the German hive.

That was the year when Lisbon-town

Saw the earth open and gulp her down,

And Braddock’s army was done so brown,

Left without a scalp to its crown.

It was on the terrible Earthquake-day

That the Deacon finished the one-hoss shay.

Now in building of chaises, I tell you what,

There is always somewhere a weakest spot, —

In hub, tire, felloe, in spring or thill,

In panel, or crossbar, or floor, or sill,

In screw, bolt, thoroughbrace, — lurking still,

Find it somewhere you must and will, —

Above or below, or within or without, —

And that’s the reason, beyond a doubt,

A chaise breaks down, but doesn’t wear out.

But the Deacon swore (as Deacons do,

With an “I dew vum,” or an “I tell yeou”)

He would build one shay to beat the taown

’N’ the keounty ’n’ all the kentry raoun’;

It should be so built that it couldn’ break daown:

“Fur,” said the Deacon, “’tis mighty plain

Thut the weakes’ place mus’ stan’ the strain;

’N’ the way t’ fix it, uz I maintain,

Is only jest T’ make that place uz strong uz the rest.”

So the Deacon inquired of the village folk

Where he could find the strongest oak,

That couldn’t be split nor bent nor broke, —

That was for spokes and floor and sills;

He sent for lancewood to make the thills;

The crossbars were ash, from the straightest trees,

The panels of white-wood, that cuts like cheese,

But lasts like iron for things like these;

The hubs of logs from the “Settler’s ellum,” —

Last of its timber, — they couldn’t sell ’em,

Never an axe had seen their chips,

And the wedges flew from between their lips,

Their blunt ends frizzled like celery-tips;

Step and prop-iron, bolt and screw,

Spring, tire, axle, and linchpin too,

Steel of the finest, bright and blue;

Thoroughbrace bison-skin, thick and wide;

Boot, top, dasher, from tough old hide

Found in the pit when the tanner died.

That was the way he “put her through.”

“There!” said the Deacon, “naow she’ll dew!”

Do! I tell you, I rather guess

She was a wonder, and nothing less!

Colts grew horses, beards turned gray,

Deacon and deaconess dropped away,

Children and grandchildren — where were they?

But there stood the stout old one-hoss shay

As fresh as on Lisbon-earthquake-day!

EIGHTEEN HUNDRED; — it came and found

The Deacon’s masterpiece strong and sound.

Eighteen hundred increased by ten; —

“Hahnsum kerridge” they called it then.

Eighteen hundred and twenty came; —

Running as usual; much the same.

Thirty and forty at last arrive,

And then come fifty, and FIFTY-FIVE.

Little of all we value here

Wakes on the morn of its hundreth year

Without both feeling and looking queer.

In fact, there’s nothing that keeps its youth,

So far as I know, but a tree and truth.

(This is a moral that runs at large;

Take it. — You’re welcome. — No extra charge.)

FIRST OF NOVEMBER, — the Earthquake-day, —

There are traces of age in the one-hoss shay,

A general flavor of mild decay,

But nothing local, as one may say.

There couldn’t be, — for the Deacon’s art

Had made it so like in every part

That there wasn’t a chance for one to start.

For the wheels were just as strong as the thills,

And the floor was just as strong as the sills,

And the panels just as strong as the floor,

And the whipple-tree neither less nor more,

And the back crossbar as strong as the fore,

And spring and axle and hub encore.

And yet, as a whole, it is past a doubt

In another hour it will be worn out!

First of November, ’Fifty-five!

This morning the parson takes a drive.

Now, small boys, get out of the way!

Here comes the wonderful one-hoss shay,

Drawn by a rat-tailed, ewe-necked bay.

“Huddup!” said the parson. — Off went they.

The parson was working his Sunday’s text, —

Had got to fifthly, and stopped perplexed

At what the — Moses — was coming next.

All at once the horse stood still,

Close by the meet’n’-house on the hill.

First a shiver, and then a thrill,

Then something decidedly like a spill, —

And the parson was sitting upon a rock,

At half past nine by the meet’n-house clock, —

Just the hour of the Earthquake shock!

What do you think the parson found,

When he got up and stared around?

The poor old chaise in a heap or mound,

As if it had been to the mill and ground!

You see, of course, if you’re not a dunce,

How it went to pieces all at once, —

All at once, and nothing first, —

Just as bubbles do when they burst.

End of the wonderful one-hoss shay.

Logic is logic. That’s all I say.

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

#58

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/

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

#59
post #24

Earlier quoted context omitted.

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 become…

Also, something not explicitly stated in this thread is that most of the most important science happens in the first year the rover / lander is there on Mars. You really want that first year to be successful, and anything beyond that is bonus.

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

#60
post #28

Earlier quoted context omitted.

> 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 n…

I'd go as far as saying "useful science" doesn't have much meaning. The misunderstanding comes from the conflation of "science" and "engineering". The reason engineering exists is to be useful: to create artifacts and technology to make our lives better, easier, etc. But science only has three uses: to inform engineering; to satisfy our human curiosity; and to beget more science. Any "usefulness" here is of a very na…

>and to beget more science. but that's not the same as being useful.

For those looking to keep a job in sciences, begetting more science sounds pretty darn useful

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