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Commies4Lyfe t1_j1sif4f wrote

Reply to comment by [deleted] in Meet the amateur astronomer who found a lost NASA satellite by jarvedttudd

Genuine question. Do NASA just give really poor life expectancies to their stuff? I feel like I always see that they say something eill only last for so long, bit then it just carries on.

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skucera t1_j1sjzx0 wrote

It’s a worst-case scenario estimate. If the worst-case scenario still justifies the cost, then the project is worth moving forward with trying to get prioritized into the budget. Of course, they buy the absolute best (highest-reliability) gear, and have some of the most sophisticated failure analysis and prevention tools in the world, which contributes to extended longevity.

Basically, it’s better to under-promise and over-deliver, especially when you’re the part of the government that has to really struggle for funding.

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SuddenlyLucid t1_j1slgc6 wrote

But we're not used to it, because almost everyone else does the opposite, NASA is pretty unique in that regard.

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sigmund14 t1_j1t0dbk wrote

I wish everyone would do the same as NASA. It wouldn't really be profitable, but the brand loyalty would be through the roof.

Instead, we have planned obsolescence - deliberate failure of some component that is impossible to replace / repair. Creating trash just for profits.

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ballrus_walsack t1_j1t3uuy wrote

I always buy NASA branded electronics.

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iaredavid t1_j1tbmz0 wrote

Tempurpedic! Freeze dried ice cream!

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Baremegigjen t1_j1th2n2 wrote

Velcro. In fact it’s the primary method for attaching the reflective blanket that protects the bus (body) of satellites.

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kinboyatuwo t1_j1u8shf wrote

Or just ensure stuff is serviceable. I would take that.

I had a vacuum a few years ago and the brush head failed at the bearing and tore it and the plastic connector apart.

I couldn’t find a replacement head (had ordered 3 that were listed as correct and none fit) and the plastic part I had to “make” by filling with epoxy and using a dremmel to make the recess.

3D printing helps, we just need better ways to get the shapes into the system now. But we need a requirement for a parts availability for day 10 years or the company has to give you a new one.

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MeagoDK t1_j1uba36 wrote

Sometimes the replacement cost as much as a new machine. Had to replace the rack in my dishwasher (it was rusten) ended up buying a new dishwasher as it was not that much more.

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kinboyatuwo t1_j1unwls wrote

Ya it’s crazy. We need more supply chain but also salvage. I’ll bet someone not far away had a failed one and tossed it that had a rack that was fine.

Only way it will happen is legislation sadly.

I would pay extra to know parts are available ans affordable for 20y.

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MeagoDK t1_j1uvbld wrote

Yup a thing they would improve it would be to have very standard hardware interfaces. If a rack would always fit then you can easily start saving used but good racks when someone throws out a rack and it would be much to find the broken part.

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kinboyatuwo t1_j1uxn6x wrote

Shoot, they even make changes in their own line up and year to year. You would think some consistency would lower costs for them but someone has done the math I suspect.

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IkiOLoj t1_j1tr48l wrote

That's the luxury of not being a for profit organization, they don't have to take a benefit somewhere so they can invest the whole budget in the product. If you were making a product expected to work for 2 years lasting 5, you'd probably be screwing your shareholders somewhere as you would be wasting their potential dividends.

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MeagoDK t1_j1ubh2b wrote

In this case nasa just screws the senators because the budget was for 2 years, not 5 years. So they need money for 3 more years.

NASA absolutely have shareholders, they are just government officials and they play politics with them to get their budget and project approvals

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skucera t1_j1upltj wrote

The budget to “run science” on a craft is pennies compared to the cost of building, launching, and landing the craft.

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MeagoDK t1_j1uua3c wrote

Insight was:(approx)

  • Spacecraft 600 million.
  • Launch ticket 160 million.
  • 2 years operation 60 million.

If we assume insight will last:

  • 10 years, that's 300 million, 30% of total budget
  • 15 years, that's 450 million, 37% of total budget
  • 20 years, that's 600 million, 44% of total budget

A 820 million budget is much easier to approve than 1360 million budget

It's not pennies, you are simply wrong.

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skucera t1_j1v2pr1 wrote

Primary mission operations are $30MM/yr; this includes launch activities, landing, and commissioning. The actual cost of the next four years was roughly $15MM/yr. It goes in the annual budget, and congress views this as a good return on investment. If they end up objecting, they can always choose to not fund it.

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MeagoDK t1_j1xj8ug wrote

Even if you halve the operational cost, it's stil not pennies.

And yes off cause they do. That's the whole point. It's easier to approve incremental than all at once

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Henhouse20 t1_j1t5tnb wrote

Not unique at all in the space industry. Everyone else does the same......their spacecraft typically all last longer than their design life

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danielv123 t1_j1u2n3k wrote

The important distinction is that they are building a thing to work for 2 years, not to fail after 2 years.

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OtisTetraxReigns t1_j1sr1oh wrote

Under promise, over-engineer.

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Mr_Zaroc t1_j1tqxgu wrote

Yes we have a fail-safe, but how about a second fail-safe?

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Used-Towel5687 t1_j1tsbob wrote

Not nuff money. tank, jet good 👍

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Mr_Zaroc t1_j1ttgr4 wrote

YOLO (You only launch once)

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Used-Towel5687 t1_j1xz92j wrote

Insufferably accurate… if only we were born on a planet that isn’t trying to destroy one another every 50 years…. It’s a really great topic to talk about, as the more knowledgeable the general public is, the more information spreads, that everybody IS actually trying to live in harmony…. Nope, nukes.

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caitejane310 t1_j1t9anf wrote

Yeah, idk why I was surprised at all the little tests that us common folk wouldn't even think of. I recently watched Good Night Oppy (highly recommend) and thought it was pretty neat how they would replicate the conditions the rovers were in so they could try and figure out how to get them unstuck.

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skucera t1_j1up8d7 wrote

Also, The Martian was accurate in how they have an exact copy of every rover and lander they send out so that they can try out fixes/solutions on Earth before they send them out.

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btribble t1_j1tsz9u wrote

Yes, when you can set conservative goals and then over-deliver it always looks good. If you're not under promising and over delivering at your work, you're doing it wrong.

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EpiicPenguin t1_j1tyvq8 wrote

> and have some of the most sophisticated failure analysis and prevention tools in the world, which contributes to extended longevity.

Which is why it still boggles my mind that they didn’t add a brush tool to clean off the solar panels on insight lander. They were literally willing to drop rocks on the panels durring the mission, but adding a 5$ brush to the arm thats already on the billion dollar martian lander, apparently thats not an option.

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UseApasswordManager t1_j1ud9so wrote

That wiper is also going to fail someday, and they figure you get more life out of x kg of extra solar panels than they would from an x kg wiper arm

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skucera t1_j1uo7w2 wrote

On all prior Mars landers, NASA has relied on Martian wind to clean off the solar panels. That worked fine here, as the lander was active for over twice its planned mission.

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smithsp86 t1_j1xndom wrote

It’s also a budget strategy thing. Using Spirit and Opportunity as examples. It’s much easier to stay within budget if they only put 90 days on paper. Once you have the hardware in place it becomes essentially automatic to get extra funding to keep operating. There’s just no sense placing the long term plan in the original proposal.

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Original-Aerie8 t1_j1tj1pp wrote

> worst-case scenario estimate

Not to be rude, but that seems like a empty word, instead of a explanation at how they arrive at those numbers. What do you base this on?

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skucera t1_j1uovax wrote

You perform a Failure Mode and Effects Analysis (FMEA). Once you know the failure modes that you can’t design out of the system, you design mitigation for the rest. You then add redundancy for those modes you can’t mitigate. Finally, you take the probability of an individual critical failure happening and calculate the duration before there is X% chance that a critical failure has occurred, and that’s your planned mission length. If it’s too short, you put in more mitigation or redundancy.

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coriolis7 t1_j1skhk9 wrote

They design everything to have an extremely high chance of surviving the mission life at full operational capability. If they design each system to have a 50% chance of surviving 2 years, and there are 5 systems, then there’s only a 3% chance the mission will actually make it to 2 years.

Even then, if NASA wants 2 full years, then they’ll shoot for a high likelihood of meeting it, like 95+%. That means there’s a decent chance it’ll make it well past 2 years.

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11thDimensionalRandy t1_j1sl5n5 wrote

They generally give lower end estimates.

If you followed along the JWST launch, it was often said that it went so well that it extended the length of the mission, but ehat happened is that the Ariane rocket performed perfectly within instead of its expected capabilities and no fuel had to be wasted on correcting mistakes, leaving more fuel for the satellite to make the adjustments required to remain fully operational at L2.

NASA suffers from a lot of restrictions, and failures are valued a lot more than successes, so rather than claiming the JWST can operate for 20 years, having something happen to cut that number down to 15 years and dooming the agency after a huge project underdelivered, they work with lower expectations.

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Shabbona1 t1_j1sl445 wrote

So 1) space is super hostile. Not an ideal environment to operate anything in.

  1. everything eventually needs maintenance and it's basically impossible to perform maintenance on satellites so think how long a complex device would function on earth without anybody touching it ever again.

Both of the above lead to 3) they engineer the living shit out of those things, and damn near everything has a "safety factor." Which, in short, means they take whatever they think the operating threshold is for a component and divide it by 2 at the very least when doing their math on what they think the component can withstand for any given attribute. This is a common thing in almost every product developed. Ever see a ladder that says rated for 250 lbs? Odds are it won't fail until you put 500-750lbs on it. But nobody says that number because you can't guarantee it won't fail just before 500 and you don't want a user to find out, so you say 250lbs.

What this means is NASA guarantees the satellite will run for 2 years, but it will likely run for longer than that. Plus, every good engineer operates under the rule of "under promise, over deliver." Tell your superiors it will definitely last for 2yrs, engineer it with safety factors to guarantee 2 years, and then over deliver when it ends up lasting for 2.5, or 3, or in this case, 5.

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ClamatoDiver t1_j1smgt8 wrote

They pull a Scotty.

Cap'n I canna give ye the engines for 4 hours!

Twenty minutes later the engines are working.

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za419 t1_j1t4kek wrote

NASA gives minimum lifespans, not averages or expectations.

In other words, when NASA says "the rover will last 90 days", they mean "the rover will last no less than 90 days".

Consequently, everything should at least hit that lifespan. If it doesn't, something fucked up and the mission failed. That also means that those 90 days is the time NASA wants the spacecraft to last to consider launching it to have been worthwhile.

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Jaegermeiste t1_j1taogj wrote

Well, NLT 90 days, unless we yeet it into a planet first, because maybe nobody cross checked the units

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za419 t1_j1ths8f wrote

Well, that would fall under "something fucked up and the mission failed"!

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suicidaleggroll t1_j1sz4pv wrote

There’s a big difference between “we believe this system will last about 2 years”, and “this system has been designed so that it WILL last at least 2 years”

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TheDorkNite1 t1_j1sr2pg wrote

>Do NASA just give really poor life expectancies to their stuff?

It's fascinating to see how long some of their projects go past their dates. Opportunity rover lasted more than 14 years when it was planned for only 3 months.

Right now on Mars the little Ingenuity chopper is still kicking more than a year past its goals of 5 flights.

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boredcircuits t1_j1t2mx2 wrote

It's not a "life expectancy." A better term is "minimum requirement." Basically, they tell the contractors that everything needs to last at least X years, and everything is designed around that. Fuel tanks, redundancies, etc.

Compare this to a consumer device, where the specifications might have an average life requirement. For example, a phone manufacturer might specify a battery that degrades 20% after 400 charge cycles. What they care about is the average: some will live longer than that, and some will be less. That's ok because they'll just warrantee the bad batteries.

But you usually can't just say "oops, sorry" and replace a faulty battery in something that goes to space. (Hubble's mirror being the notable exception.) So NASA requires everything to satisfy the minimum mission requirements. We shouldn't be surprised when something outlives the minimum, really.

Also, NASA has a knack for extending missions as hardware fails. Finding unplanned uses for mostly-operational hardware. Look up Kepler for a great example.

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keastes t1_j1tiggu wrote

For good reason, NASA likes to overengineer and make pessimistic estimates. Just look at the service life's of Opportunity, Pathfinder, the fact that Apollo 13 made it back...

Ground side we have the luxury of writing the safety regs in blood.

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Fernelz t1_j1t2ngg wrote

They're built to last and with high quality.

The 2 years of mission time just means a 99% chance to be fully functional for the full 2 years. After that it's just a matter of individual parts failing until full contact loss. So after 2 years it can still do everything it could at launch but at year 4 it's still doing some stuff just maybe not everything.

The whole 2 year but really 5 year thing is also very helpful for funding. It looks good if they can say "yeah the last mission you paid for was a 2 year mission that lasted 5"

PS: this is just my understanding of it, please correct me if I'm wrong

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SquarePegRoundWorld t1_j1sk1yq wrote

I think it is more about how much money are they gonna ask congress for. Probably harder to secure more money for longer missions and easier to ask for extensions on "shorter" missions that are working well.

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Shyssiryxius t1_j1tlb2l wrote

It's not just the design life but usually the life of the project itself. When you hear that the Curiosity rover was designed to last 6 months that's the amount of time they essentially budgeted for for the project including wages for the teams that operate the hardware. Obviously by the time the rover arrives 18 months later the person doing the NASA budget can then ask for more money to expand the project timeframe, and as long as the hardware continues to function this generally happens YoY.

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RG3akaAndre3000 t1_j1u41z0 wrote

Space Vehicles and programs are usually assessed and given a “Probability of Success”. NASA usually doesn’t launch anything without a Ps of 95%.

So if NASA has a program that is supposed to have a 2 year mission life, they would launch only when they have a design that has a 95% probability of success. Well if the spacecraft has a 95% chance of lasting 2 years, it’s not like it’s gonna crap out on 2 years and 1 day. It’s got a pretty good chance to keep going.

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doobie042 t1_j1sz9b5 wrote

I just wish my appliances were like that.... They don't last more than a year or two these days without hefty repair bills.

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A-Cheeseburger t1_j1t9182 wrote

It’s easier to estimate the cold, crushing vacuum of space will destroy something in a couple of years rather than pray to Jesus that nothing happens for 20.

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Kevimaster t1_j1tfjcs wrote

Under promise and over deliver.

NASA gets huge amounts of public scrutiny whenever anything goes wrong. "$132 million spacecraft breaks 5 years into a 6 year mission" isn't the kind of headline they want. "Spacecraft that was only supposed to last 2 years lasted for 5 years" is the kind of headline they want.

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foolfromhell t1_j1v0vg6 wrote

95% of the science of a mission will be achieved within the expected lifespan of a mission. After that, everything is extra.

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