
Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission - jimktrains2
https://www.nytimes.com/2019/02/13/science/mars-opportunity-rover-dead.html
======
slg
Opportunity's and Spirit's original missions were planned to last 90 Martian
days each. They ended up lasting over 8,000 combined. That is almost as
impressive as getting the rovers to Mars in the first place.

~~~
Retric
That story is very much over sold. They defiantly designed the things with a
longer lifespan in mind. NASA simply had more reasonable minimum specks so if
they died on day 220 nobody would call the program a failure.

~~~
sramsay
Oversold?

A group of engineers put a working robot on a moving object 140 _million_
miles away, and that robot trucked along for _fourteen years_.

I honestly do not see any aspect of this which is not totally and completely
astonishing, marvelous, and awe-inspiring.

~~~
Retric
They designed it for a winter which means at least 687+ earth days days was
considered achievable. Dust was expected to be a larger issue and in many ways
they lucked out, but more so as a calculated risk than blind luck.

Distance makes little difference past the first day. Doing the same thing on
the moon would not be easier becase it’s closer. It’s local conditions that
make this hard more so than simply getting to that point.

~~~
proactivesvcs
I can assure you that the distance took its toll on the rovers, in my
understanding. Their wheel surfaces eroded, oil pumps failed, bearings
degraded and they ended up dragging dead wheels in the end.

~~~
jamescostian
Are you talking about the distance the rovers traveled while on mars? Because
that's not what Retric is talking about. Retric is talking about the distance
from the earth to mars (hence why they compared it to the moon).

~~~
proactivesvcs
Ah, my mistake; I misunderstood their comment.

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aspectmin
Steven Squyres, the Principal Scientist of the program came to Microsoft to
give a talk. One of the best talks I’ve been to.

So many interesting tidbits like the parts about the rovers expected short
lifetime due to the dust, and how (if I remember correctly) they fixed this by
shaking the solar panels like wings.

He talked about the rover drivers, and how they all had to live in special
light cycle controlled buildings to get them used to working on Martian days
vs. Earth (the extra hour adds up over time).

He wrote a book, a worthy read. The printing I got had some amazing pictures
in it:

[https://www.amazon.com/Roving-Mars-Spirit-Opportunity-
Explor...](https://www.amazon.com/Roving-Mars-Spirit-Opportunity-Exploration-
ebook/dp/B000FCKC9M/ref=mp_s_a_1_1?ie=UTF8&qid=1550107198&sr=8-1&pi=AC_SX236_SY340_QL65&keywords=steven+squyres&dpPl=1&dpID=41NPVsOJAKL&ref=plSrch)

RIP Opportunity. An amazing testament to our need to explore.

~~~
dbg31415
I was really fortunate to have him as an astronomy professor right around the
time of the launch. He's great at making complex things easy to understand,
and his enthusiasm is contagious. Highly recommend his book, but if you've
only got an hour here's a good video conversation.

* Roving Mars with Steve Squyres - Conversations with History - YouTube || [https://www.youtube.com/watch?v=NI6KEzsb26U](https://www.youtube.com/watch?v=NI6KEzsb26U)

------
wiremine
Was looking through Opportunity's Wikipedia page, and found this cool
comparison of the embedded systems used in Mars rovers:

[https://en.wikipedia.org/wiki/Comparison_of_embedded_compute...](https://en.wikipedia.org/wiki/Comparison_of_embedded_computer_systems_on_board_the_Mars_rovers)

That lead me to the RAD6000 page, which was new to me:

[https://en.wikipedia.org/wiki/IBM_RAD6000](https://en.wikipedia.org/wiki/IBM_RAD6000)

"Reported to have a unit cost somewhere between US$200,000 and US$300,000,
RAD6000 computers were released for sale in the general commercial market in
1996"

Anybody know why the per unit cost is so high? Low yields or is it that much
more expensive?

~~~
luizfzs
I saw a video once saying that SpaceX uses general purpose computers on the
rockets instead of specific purpose hardware. If I'm not mistaken, they amount
to 6 and have a checking system to assure the output of them is the same.

~~~
tzs
Those "have N copies and compare them" systems then have the issue that
whatever does the comparison is a single point of failure. You could use
multiple comparison units and have a second level comparison check them, but
then that is your single point of failure, and so on.

I've been told, but never actually looked it up, that there is a theorem that
proves you always have to have at least one single point of failure.

I don't know if the following is actually true, or just a rumor, but I've
heard that at least one aircraft whose mission called for very high
reliability didn't have a comparison unit: the redundancy extended all the way
to having the 3 independent flight control computers each control a separate
actuator on each flight control surface. If one of the systems went bad and
tried to move the surface incorrectly, the other two would physically
overpower it.

That still has a single point of failure, but now that point is the control
surface itself. If your control surface itself has failed it no longer matters
if the 3 computers controlling it agree.

~~~
Strilanc
> _I 've been told, but never actually looked it up, that there is a theorem
> that proves you always have to have at least one single point of failure._

In what context? There's a theorem that arbitrarily-reliable computation can
be done with noisy components, as long as the noise is below some threshold
(e.g. picture less than 1 error per 10 operations). [1]

1: von Neumann, J. (1956). "Probabilistic Logics and Synthesis of Reliable
Organisms from Unreliable Components", in Automata Studies, eds. C. Shannon
and J. McCarthy, Princeton University Press, pp. 43–98
[http://www.cyclify.com/wiki/images/a/af/Von_Neumann_Probabil...](http://www.cyclify.com/wiki/images/a/af/Von_Neumann_Probabilistic_Logics_and_the_Synthesis_of_Reliable_Organisms_from_Unreliable_Components.pdf)

------
Timothycquinn
Please have one minute of silence to remember this wonderful machine that gave
us all so much...

Kudos to all those who contributed to make this such an overwhelming success.

Science FTW.

~~~
slowhand09
Earth minute or Martian minute?

~~~
Timothycquinn
Excellent question. I assumed that one mars minute differs from an earth
minute but I just learned that they don't. Seconds, minutes and hours are
universal. Hours in a day is what varies by planets, moons etc. Funny that I
never thought of that before :)

~~~
Evidlo
It just depends on what your definition of a Martian minute is. If you define
it as 1/(24*60) of a Martian day, it is different from an Earth minute.

~~~
m3at
You're likely joking, but just in case: on earth the second is not defined as
a fraction of the day, it's a SI unit defined as a constant count of energy
level variations of an caesium-133 atom.

~~~
Timothycquinn
Thanks for that clarification. After this, I was able to find the
International System of Units Wikipedia page which clearly defines a second as
per your summary. It's a relief to see that it's a constant formula like that
of the Kilogram.

~~~
craftyguy
I was suprised to learn (from the wiki page) that the kelvin, mole, and ampere
do not have exact numerical definitions yet, though I guess that's expected to
change in May of this year.

And then there's the candela, still basically defined by how luminous whale
blubber is when it is burning:

> Current (1979): The luminous intensity, in a given direction, of a source
> that emits monochromatic radiation of frequency 5.4×1014 hertz and that has
> a radiant intensity in that direction of 1 / 683 watt per steradian.

> Note: both old and new definitions are approximately the luminous intensity
> of a whale blubber candle burning modestly bright, in the late 19th century
> called a "candlepower" or a "candle".

~~~
kevingrahl
What happens in May?

~~~
craftyguy
World Metrology Day, where acceptance of these standards will be voted on.

[https://www.nist.gov/news-events/news/2018/11/historic-
vote-...](https://www.nist.gov/news-events/news/2018/11/historic-vote-ties-
kilogram-and-other-units-natural-constants)

------
lykr0n
End of an era. We'll meet Opportunity again one day.

Same thing happened with Cassini. It's kinda poetic to see these outposts of
Humanity's reach fade out after a sublime performance.

~~~
pjmlp
More interesting would be when someone else from another species finds them in
a couple of million years in the future and wonders what their purpose was all
about.

~~~
michaelbuckbee
Cassini was deliberately pushed into Saturn's atmosphere and destroyed (so as
not to potentially contaminate habitable worlds) so we probably don't need to
worry about that.

Also, there's a great documentary TV series called "7 Days Out" on Netflix
which covers the last week of the Cassini mission.

~~~
gebeeson
I watched that show "7 Days Out" specifically for the Cassini mission. It did
not disappoint. There were feelings involved.

------
torpfactory
You know the craziest thing about all of the mars exploration programs is to
me?

The first time there is an entire full-up test of the system is live, AT MARS.
There isn't a good way to test the entire entry descent and landing sequence
because the earth's atmosphere is so different than mars. I know NASA works
hard to test parts of it in the vicinity of earth, but I can't imagine
designing something so complicated (especially the system for curiosity) and
then not being able to test it completely before the real thing.

~~~
FrojoS
I've actually read, that the upper part of the atmosphere, where a returning
Falcon 9 booster does retro burns to slow down, is similar to Mars (in terms
of pressure I guess).

edit: found a paper on the topic
[https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700...](https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170008725.pdf)

also: [https://arstechnica.com/science/2016/04/spacex-has-
already-d...](https://arstechnica.com/science/2016/04/spacex-has-already-
demonstrated-its-key-mars-landing-tech-with-the-falcon-9/)

~~~
torpfactory
I had heard about them doing some study of using an inflatable heat shield and
testing in earth's upper. I guess it could be used for Earth or Mars. Neat!

Link:
[https://www.youtube.com/watch?v=ojgDZZIsWA4](https://www.youtube.com/watch?v=ojgDZZIsWA4)

------
dsfyu404ed
Opportunity is going to be the standard for longevity that all future rovers
are measured against until one surpasses it.

If you said you expected a rover to last 5yr in 2004 you'd have been called
crazy. Here we are in 2019 and after ~15yr of Opportunity driving around up
there the idea of rover lasting 5yr or seems perfectly normal. Opportunity has
raised the bar for all future missions.

~~~
brandonjm
Curiosity is doing well at about 6.5 years and had a 2 year mission but it
probably won't stay fully operational that long. Its RTG could last that long
but it will eventually stop producing enough power for the rover to move.

------
gibolt
Scott Manley has some interesting tidbits, as always
[https://youtu.be/w2oFtu_KAbI](https://youtu.be/w2oFtu_KAbI)

------
sneakernets
Don't give up just yet, guys! Get one of the new rovers to find some water on
mars, take a microfiber cloth...maybe a squeegee...

------
sanj
Is it possible for someone other than NASA to send a message to the rover? I'd
be happy throwing a little money at a project to ping it monthly to see if
there is a response.

~~~
ChuckMcM
Yes and unlikely :-) The protocols are all documented but the ability to
receive signals from the rover requires a pretty sensitive receiver and
antenna combination. If you have the resources to build a 10m or 15m steerable
radio antenna parabolic dish then you could probably manage it.

~~~
jacquesm
That can't be that expensive unless you want it to be storm proofed. But it
wouldn't be super cheap either, the receiver is probably going to be a bigger
problem.

[http://www.astrosurf.com/luxorion/dish-antenna-
building.htm](http://www.astrosurf.com/luxorion/dish-antenna-building.htm)

Would be a good starting point. But keeping it stable under wind load is going
to be the major challenge. That would be one heck of a project, it would
likely take a few years of your time to pull it off.

~~~
ChuckMcM
This quora answer ([https://www.quora.com/What-bands-signals-and-protocols-
are-u...](https://www.quora.com/What-bands-signals-and-protocols-are-used-in-
the-communication-from-the-Mars-rovers-satellites-to-Earths-NASA-ISRO-and-
other-agencies)) claims that even the 70m DSN antennas have a hard time
hearing the rover to earth transmissions. That is 10x the diameter so 1000x
the surface area of a 4.8m dish like the one the guy built.

That said, there are no doubt interesting hacks you can do to help this but
steerability is always going to be a concern to maximize the SNR of the very
weak signal coming from the rover.

~~~
jacquesm
Yes, the precision required would be insane. That is _also_ what makes this an
interesting project, even if you fail you will still learn a ton about all
kinds of engineering principles. Expensive lesson though!

Another big factor would likely be how far Mars is away from Earth, at the
close extreme it will probably be substantially easier to pull this off.

What an interesting article by the way, thank you for that link.

------
duxup
It was such an amazing mission and it went so well.

The idea that we send a robot to another planet and it drives around for that
long still astounds me.

------
sandis
CCC talk on Curiosity rover onboard computers, for those interested -
[https://media.ccc.de/v/35c3-9783-the_mars_rover_on-
board_com...](https://media.ccc.de/v/35c3-9783-the_mars_rover_on-
board_computer) (different rover, different CPU - RAD750 instead of RAD6000
that's on Opportunity)

------
tannhaeuser
I'm feeling humbled by NASA's achievements compared to those of our profession
here wrt sustainability and longevity.

~~~
Entangled
I built some warehousing apps in VFP 20 years ago and they're still running
fine. Every time I go ship something the owner asks me to prune and reindex
the DB and that's it, another year running smooth.

~~~
nobleach
CA Clipper app that I updated to Visual Fox Pro back in 1998 is still chugging
along running an oil company's accounts payable/receivable.

------
zaarn
I'm really sad that the mission is over, it was an amazing piece of hardware!

Thanks Opportunity, for all the knowledge you gave us. Thanks for the amazing
pictures you sent us. Rest in Peace.

------
dba7dba
In an IT industry magazine website (Information Week? not sure) had an article
about an IT engineer at JPL who was picked/trained to be one of the drivers of
the rovers. He was just a normal IT guy, but got the chance to be a driver for
the rover.

He recalled that the first night after he spent a day driving the rover on
Mars, he couldn't sleep at home. He had just driven a vehicle on the Mars.
Certainly one of the first in human history.

------
perfmode
How much money would you pay me if I were to travel to Mars, find it, and
bring it home?

~~~
Jetroid
I'd argue that Opportunity is already home...

~~~
perfmode
Fair. I'm embarrassed to have been so presumptuous.

------
rdl
It will be interesting to go visit this in person in 10-20 years.

------
FullMetalBitch
And it will never be forgotten.

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deusofnull
RIP we will never forget you.

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speeq
[https://xkcd.com/1504/](https://xkcd.com/1504/)

~~~
msoucy
And the related follow-up: [https://xkcd.com/2111/](https://xkcd.com/2111/)

~~~
trykondev
This one always breaks my heart:
[https://xkcd.com/695/](https://xkcd.com/695/)

(It's about Spirit, not Opportunity, but still).

~~~
thomasfortes
Some people weren't happy, so...

(fan made) [https://i.imgur.com/VbKV9DF.jpg](https://i.imgur.com/VbKV9DF.jpg)

------
pooya13
And it was supposed to last 90 days...

~~~
dogma1138
It wasn’t supposed to last only 90 days, the initial mission specifications
were for a 90 day mission.

While it’s an engineering marvel no one thought that it would last only 90
days if it successfully landed and deployed, the 90 days was a minimum figure
for the design and also the initial operating budget for the mission.

~~~
blhack
I too get annoyed at seeing this fun fact.

It's really hard to engineer something that will last 90 days. It's much
easier to overbuilld it, which fulfills the requirement of 90 days.

It was designed to last as long as possible within the given weight and size
budget.

~~~
dogma1138
Yep one of the reasons that it lasted so long was that it was too small for an
RTG so as long as it the solar panels were still somewhat intact it could
operate even if the battery would essentially be completely dead.

The 90 day figure is simply the time period for which NASA asked for money to
operate the thing no one is going to ask for 2, 5 not to mention 15 years
worth of operating budget you usually get a few months at the time and extend
it based on your needs.

------
mudil
[https://outline.com/L2pyN4](https://outline.com/L2pyN4)

------
bitxbitxbitcoin
Fare thee well.

------
gus_massa
Relevant xkcd: [https://xkcd.com/1504/](https://xkcd.com/1504/)

~~~
Shelnutt2
Today's [https://xkcd.com/2111/](https://xkcd.com/2111/)

------
triptych
Seems like they could just send a drone to go wipe off the solar panels...

~~~
athenot
I'm reminded of this entry in the wikiwiki: "Just" is a dangerous word.

[http://wiki.c2.com/?JustIsaDangerousWord](http://wiki.c2.com/?JustIsaDangerousWord)

~~~
escapecharacter
I recall having a chat with someone with a poor understanding of chemistry,
and they asked why we couldn't "just have tiny robots take the carbon dioxide
and turn it back into gasoline again"

~~~
jackhack
I think it's safe to say that person had a poor understanding of a lot of
things, not just chemistry.

------
buboard
Self driving terraforming robots would be an excellent testbed for AI
technologies. What is the reason for pushing humans again?

~~~
colordrops
The discussion around humans vs robots in space in historically deep
conversation with scientific, technical, and philosophical aspects. Do not
simply brush it off without understanding the context.

~~~
buboard
that doesnt answer my question

~~~
anyfoo
AI doesn't work nearly as well as you seem to think it does. For something as
excruciatingly difficult as a space mission, humans have proven to be well up
to the task. The headline of this article here is one illustrative data point.

Furthermore, many methods that are currently classified as "AI" act because of
very complex and often opaque emergent behavior, and we often have a hard time
(or don't know at all) why a CNN for example behaves as it does, or even how
exactly it behaves. Do you want something that you neither understand nor can
predict to perform a crucial job in your space mission?

~~~
vkou
If space exploration were a robot-first, robot-only affair, we would probably
have cheaper, better, far more capable robots today... And also more humans in
space then the 3 that currently occupy the ISS.

~~~
buboard
actually, since the end of the cold war, space exploration is a robot-first
endeavor (and apart from ISS robot-only -- think of the countless exploratory
missions, hubble, the rovers etc). the ISS barely counts as space exploration

------
mrwnmonm
Seriously, what is the point of space exploration anyway? and what if we found
water on Mars? shouldn't it be a huge amount of water to support life?

~~~
agildehaus
We've found water on Mars, but we've also found ancient river and lake beds,
deltas, and minerals that can only be found in water on areas of Mars where no
water currently exists.

We wouldn't know any of that without having gone there to explore it.

By learning about the mechanisms behind why Mars went from water-rich planet
to its current state, we learn more about what could happen us, its closest
neighbor.

There also remains the possibility Mars could currently harbor life, or once
did and there's evidence of that to uncover. Mars represents our best chance
of finding direct evidence of extraterrestrial life.

Please try to have a richer view of this.

