

Why This Mars Rover Has Lasted 3,560 Days Longer Than Expected - cryptoz
http://www.sfgate.com/technology/businessinsider/article/Why-This-Mars-Rover-Has-Lasted-3-560-Days-Longer-5173078.php

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nightcracker
What an awful article. All factual information can be summarized in two
sentences:

"The mars rover lasted longer than expected because we did not anticipate the
strong winds blowing dust off the solar panels. Furthermore, the rocker-bogie
suspension system kept the machine from toppling over."

Everything else was non-information towards the subject. Claims that their
machines are American, exquisite, sturdy, creative, well designed, excellent,
fantastic and well built explain nothing.

~~~
jeffdavis
Tough criticism.

It was designed for a few months. On its 10-year anniversary, I think it's
worthy of a news article.

Sure... not much to say, but then the article wasn't very long, either. A
couple facts, and the rest was filled with pride and other light reporting,
like the feature article that it is. I don't know much about journalism, but
it wouldn't seem out of place next to a feature about a successful
restauranteur or a dog that saved someone from drowning.

Is hard-hitting and just-the-facts the only acceptable form of journalism or
something?

To me, this was at least worth the bits it was printed with. I'm glad to know
that people still care enough to do something so well that they can launch it
on a rocket, land it on another planet, and keep it running and sending data
back to Earth for 10 years straight.

~~~
misnome
> It was designed for a few months.

It was designed to, at an absolute minimum, with everything they could
reasonably expect, work perfectly for 90 days. This is a bit of a different
statement.

~~~
jeffdavis
A strange point: so you're saying that because they designed it to last
longer, that lasting longer is not as much of an accomplishment? Like the
optimism of the engineers detracts from the results when that optimism is
realized?

Regardless, it doesn't take away from my point. Getting something to work in
that environment for a decade (I suppose I should specify that it's an Earth
decade) is quite an accomplishment.

Let a few people feel a little pride of accomplishment. And let the rest of us
feel inspired that such a feat is possible.

------
haberman
Always love this xkcd: [http://xkcd.com/695/](http://xkcd.com/695/)

~~~
giantrobothead
Why does anthropomorphizing our machines always seem to lead to sadness?

~~~
dredmorbius
There's an alternate take on the xkcd panel with a more upbeat viewpoint. I
looked for it briefly but couldn't find it.

~~~
willtheperson
Found it [http://twicsy.com/i/vTY5E](http://twicsy.com/i/vTY5E)

~~~
dredmorbius
Bingo. Thanks.

------
deletes
//slightly off topic

The rock, which has a white rim and center that is deep red, is _unlike
anything scientists_ have seen before on Mars.

Such statements insinuating that the scientists are somehow puzzled by that
fact. Of course they haven't seen it before, because it never happened. How
often do you get a rover on mars. Sooner or later a rock will get yanked from
the wheels. Media is really scraping the bottom here.

edit: My guess, looks more like something metallic, like a part of the rower
perhaps.

~~~
judk
You are being overly cynic. It is a new discovery.

~~~
BrandonMarc
Exactly.

In other news, scientists astounded the world with a new discovery on mars: a
small, hexagonal rock with a threaded cylindrical hole.

Slam-dunk proof Mars had intelligent life at some point!

Even more amazing: it just happened to be sitting near the rover. And it
wasn't there when the rover drove up to that point.

Proof the martians are just putting evidence right in front of us, while being
sneaky at the same time! How clever of them.

------
Toenex
I was always a little dubious of the 90 day mission length. It sounded like
NASA were just giving themselves a "yeah we meant that to happen" get out if
things went bad.

~~~
Sanddancer
You need to keep in mind that the rovers also needed to survive the six months
in transit in once piece, and the airbag-assisted landing in one piece, both
of which add necessary reliability and durability factors to make sure that
the thing lasts even the 90 days. Also, you need to keep in mind that those
cleaning events came out of left field. Yeah, they were expecting to maybe get
a few extra weeks out of the rovers, but because the wind behaved in a manner
that was completely unexpected, the panels weren't as dust-caked as was
expected, which had always been the real limiting factor.

~~~
zzzcpan

      > the panels weren't as dust-caked as was expected
    

Common, this is such a lousy excuse. If dust was a big problem I'm pretty sure
they would have designed a dust-cleaning device.

~~~
gallamine
Such as what, exactly? I'm sure it was considered, but it's not that simple.
Would it involve air blasts? Liquid? A squeegee? The sand/dust content wasn't
exactly known so a scraping motion would potentially scratch the glass surface
and make things worse. Compressed air would take a tremendous amount of energy
to compress and a liquid is heavy.

------
aaron695
> Why This Mars Rover Has Lasted Longer Than Expected

It hasn't, it was designed to last this long.

But politically it's better to say it's designed for a short period in case
things go wrong.

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jfoutz
I'm sure the cost of getting the thing there overshadows the cost of
construction, but it seems really fabulously overbuilt. I'm sure the martian
environment is horrible for plastics, but heck, they only need to last 90
days. Let them get brittle and rot. (I'm assuming plastic is lighter and
therefore cheaper to transport)

I guess it's the difference between doing everything as well as possible and
then dealing with the limiting factor, vs doing just enough to meet the 90 day
goal. A classic quality vs value trade off.

~~~
elteto
"fabulously overbuilt"... not quite, think about this: you have _one_ chance
to launch it into space, send it millions of miles away, reenter atmosphere
safely and then survive a hostile environment for _only_ (?!?!?) 90 days!
There is no overbuilding, by the nature of the mission itself your Factors of
Safety [1] are through the roof!!

[1]
[http://en.wikipedia.org/wiki/Factor_of_safety](http://en.wikipedia.org/wiki/Factor_of_safety)

~~~
jfoutz
Amusingly, in this case there were two chances.

I'm saying if Spirit and Opportunity were constructed less well, perhaps we
could have afforded a third with the same budget.

I don't really have any honest way to value the difference between 10 years of
extra data vs another location (i'd guess the more data is better, but that's
hindsight bias)

Remember, every ounce of "factor of safety" is tens (or hundreds?) of
thousands of dollars.

------
dredmorbius
Recognizing the premium for any mass on the mission, I've wondered why some
sort of panel-duster (perhaps a spinning flail such as you'd find in a
carwash) wasn't designed in.

Still, the longevity and data have been truly amazing.

~~~
XorNot
You'd still have the same problem though: how do you keep a motor lubricated
in the partial pressure of a pretty good vacuum? How do you stop the duster's
brushes falling out or wearing out?

Not saying it's not possible, but if you consider things like reaction wheel
failures, there's a lot of "might last a long time, might die in a year or
two" problems in any motor in space.

~~~
dredmorbius
There are plenty of other motors on the landers, presumably the rovers haven't
been telekinesing merrily over the marscape. The brushes would be a far lower
duty-cycle item.

Depending on the brush design: something sufficient to clear the panels
periodically (say, based on noted solar degradation and/or self-inspection
photography) might work. Clearly, incidental wind has proven sufficient.

And there's a lot of engineering work on Earth which could go into testing out
the design. As I said: it's just curious that this seems to have been left to
chance. Though nobody really expected the rovers to run as long as they have.

~~~
eropple
_> There are plenty of other motors on the landers, presumably the rovers
haven't been telekinesing merrily over the marscape. The brushes would be a
far lower duty-cycle item._

But far more exposed, though. If not the motors themselves, then the mechanics
of the wiper arm.

~~~
dredmorbius
More so than camera servos or other arms on the probes?

Again: while high-reliability, low-pressure lubrication is a challenge, it's
clearly not an insurmountable one. Providing a means to ensure your only
source of energy remains viable would be useful. Failure of the dusting system
of itself wouldn't result in a mission failure. Success of it could prolong
it, and/or allow for smaller collectors (as I recall the solar panels were
oversized to allow for possible dust accumulation).

I'm thinking of some sort of rotary duster which might pass horizontally above
the panels. Less a windshield wiper design than a dual-arm rocker.

------
beloch
When the U.S. puts as much money into something as the mars rover (that isn't
for killing or spying), red-blooded 'mericans want to know they're getting
their money's worth. If you design a rover that's supposed to work for 10
years and it dies in 10 months, you F'd up. However, if you publish a Scotty
estimate of just 6 months and it lasts 10 years...

I don't buy, even for a moment, that the mars rover wasn't designed to last.
It was indeed well designed and built. The estimate for it's expected
lifetime, however, was more a function of politics than engineering.

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sokoloff
Is it too much to ask that a journalist be able to convert 10 years to days
correctly? I mean, it's true that it lasted 3560 days more, but I'm guessing
they were shooting for 3,650 days. (or 3653 days)

~~~
alexandros
it's 10 years minus 90 days (the original anticipated mission length). 3650 -
90 = 3560 days.

~~~
sokoloff
Thanks; my own reading comprehension failed me. I hate when I fall victim to
Muphry's Law. [1]

1\.
[http://en.wikipedia.org/wiki/Muphry's_law](http://en.wikipedia.org/wiki/Muphry's_law)

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dweinus
This is why is seems so terribly short-sighted to me that our most recent
rover is nuclear-powered.

~~~
Rebelgecko
Using RTGs for power gives the rover a ton more flexibility though, and helps
make the most use out of the time that it has. I remember from reading the
Mars and Me blog (written by one of the rover drivers) that the cyclical
nature of solar power put some pretty big constraints on the rovers. It wasn't
just a day/night thing, they had to be really careful about the orientation of
the rovers' solar panels during the martian winters. A lot of the time they'd
just park the rovers for the winter. Plus, the waste heat from the RTGs can be
used instead of electric heaters.

