Nasa’s Mars Rover Opportunity Concludes a 15-Year Mission
nytimes.com
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Don't take my word for it. Go out and try to make earth yourself. If you can reinvent this fundamental, elementary process, you will join Jonas Salk and Fritz Haber, and very few others, in changing The Game in a fundamental way.
Note: I think you mean humus. Hummus is "a Levantine dip or spread made from cooked, mashed chickpeas... blended with tahini, olive oil, lemon juice, salt and garlic."
I used to have a huge garden, and made a compost by barely dumping anything organic on a big pile. It worksed great: low maintenance, never one problem, plenty of compost produced.
I now live in a flat, and have composter using worms.
I can't make it practical for the love of me.
If I put it inside, I get flies, no matter how much carbonated material I put in it.
So I put it outside, but it dies from either heat, or cold.
Even when I manage to avoid the worm genocide, the process is so slow. It does produce a fantastic liquid fertilizer in mass, but the volum of organic matter consummed is nowhere close to what I need. I eat a lot of vegies and fruits, and in 2 weeks, I have to put most of it in the trash can, waiting for the worms to work on the legacy pile of trash.
Any advice ?
On to your situation. In home composting is always tricky. My wife and I do indoor/outdoor because we have a yard. In your situation, I'd advise against vermicomposting for the same reasons you listed. I was the technical manager for an enterprise vermicompost startup. Our facility was a rowhouse basement and the owner of the property was a founder. Flies are unavoidable, as is the occasional vermischwitz. They are fragile guys and minor mistakes have major consequences. The exact ratios escape me, but 1lb of healthy, mature red wigglers can consume half a pound of Green (fresh) cellulose in a day or two. We were engineering soil additive, so we supplemented heavily with Gray (dead) cellulose (cardboard, paper, etc.) In an attempt to hit profitable output. I will spare you the further details of our failure. Suffice to say that vermiculture is tricky in the best circumstances.
My suggestion to you is twofold: use the Bokashi Method (https://www.planetnatural.com/composting-101/indoor-composti...) and find a friend with a garden to offload your Bokashi Tea. That link is one of the first hits on Google (read: not vetted) because if you go this route you are going to be reading a lot and there are many roads to Rome.
This is very short due to medium, but if you'd like to discuss in depth and at length I'd be more than happy to. Both composting and waste neutralization are passions of mine. Just let me know how to contact you should you desire.
Once a robotic mission accomplishes its primary objective, NASA has a great story to tell about marginal cost vs return of additional funds. It's not that uncommon; heck they still get funding to keep the Voyager program operating.
https://en.wikipedia.org/wiki/Cleaning_event
and:
https://www.jpl.nasa.gov/missions/mer/images.cfm?id=1823
The second link shows about 18% power drop after 90 sols ~= 90 days.
Nah, it's a method for giving you a lot of wiggle room if you (or your business) fucks up in something.
NSF, too. The VLA opened in 1978 and the first data recorded by it can be reduced by the current radio astronomy analysis software. In fact the software data format developed for the VLA (FITS) is now popular with high-end camera people... 41 years later.
So, did he make it beyond Pluto or not?
There is no chance anyone involved in that program expected the rover to last for 5 years, let alone 15.
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.
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.
90 days was because they didn't think a rover would last over 90 days due to dust storms. They figured that after 90 days they'd encounter a bad dust storm that would cover the solar panels and make them unable to collect power, and thus the battery would be drained and unable to charge after 90 days.
They didn't account that the winds on mars would be able to clean the solar dust off the solar cells so well that it turned out dust storms weren't a huge issue until the latest one.
And from my understanding it wasn't the intensity of the latest storm that killed it but the part of the rover's computer that kept track of time was shot, so it wasn't able to optimize when to go to sleep and when to wake up properly, causing it to run out of charge while it was dark.
I think the book "Roving Mars" covers this the best. They were worried about a dust storm like the one that killed Opportunity, so they designed the rover to last 90 days even in the pitch darkness of a dust storm. To make sure they'd succeed even in this worst case, they added two additional petals worth of solar panels (IIRC, about a 50% increase in area) to the MERs.
Reading a contemporary description, they seemed to be very scared they wouldn't make the 90 days - hence this major and risky redesign. (The new panels had to open, and if one failed it would block off both the new solar panel, and one of the original ones.)
It worked, and so they had enough extra power to last through that first Martian year, where the winds blew the panels clean. And the rest is history.
https://web.archive.org/web/20120504171453/http://www.msnbc....
People have to be continually convinced that exploration of the solar system is a worthwhile expenditure of a lot of money that could be spent on other things. Seems obvious to those who are already thinking in the direction of where humanity is going, but most people do not.
Not to mention, science without proper PR has a disastrous level of near-term utility. See: climate science
Not surprising at all. Coached a FIRST team for several years. At this point they sell licensed robotics kits with canned instructions for kids to put together and those kids win because of time limitations. The teams that build from scratch and actually contribute discover or learn anything at all are intentionally blocked from winning. The entire program is total crap for retarded children. Meanwhile smart kids are off doing their own projects that are 1000x as complicated as the most challenging FIRST challenges. It's just turned into a money burn.
This is ridiculous, and I'm saying it is from the perspective of having been a student whose team finished fourth in FRC in a recent year (and won multiple events per year), and having volunteered and assisted multiple teams.
While it is true that a lot of lower resources teams may be better off going with commerical off the shelf (COTS) components, such as the Greyt Elevator and Greyt Intake, teams that perform at a higher level will build everything from scratch. Whether this means utilizing gussets or welding, building your own drive train or using the AndyMark prebuilt chassis.
While it is true that some kids may be better off doing research projects, there is nothing wrong with participating in a team. From my three years as a student, I was exposed to developing solutions to split messages up and verify data integrity when communicating over serial with external microprocessors, utilizing version control, setting up Continuous Integration on our repositories, first deploying apps from Cordova to developing Progressive Web Apps, which forced me to learn to use a VPS on Digital Ocean, running a docker swam on hyper.sh, and storing files on S3 and using RDS.
FIRST is what you make of it, and I'm personally glad that someone holding your opinions towards the program is no longer actively interacting with kids in the program.
Imagine if your retirement planner or accountant was off by 44X in their number crunches for you. Would you say they were good at estimating?
You think NASA is overly concerned about public perception to the tune 44x an original estimate?
I see nothing wrong with this.
Imagine you design a bridge to support 100 tons. No one would accuse you of mispredicting if it holds up at 200 tons. They will accuse you of negligence if it collapses at 105 tons.
Meanwhile software industry is... Ship to prod ASAP, hire junior devs to reach head count, outsource to overseas and contractors.
I realize the risks are different... But management gets pissed when software causes financial lost and wonder why.
I wonder whether family owned companies are closer to NASA in their testing/hiring practices?
Framed this way it's not entirely surprising they lasted longer, especially given the fortunate turn of events with the martian wind cleaning the solar panels of dust.
This of course does not in any way diminish the engineering and ingenuity involved with designing and operating the rovers.
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...
RIP Opportunity. An amazing testament to our need to explore.
* Roving Mars with Steve Squyres - Conversations with History - YouTube || https://www.youtube.com/watch?v=NI6KEzsb26U
https://en.wikipedia.org/wiki/Comparison_of_embedded_compute...
That lead me to the RAD6000 page, which was new to me:
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?
Vorago makes a cheaper option these days at $800 a chip: https://www.voragotech.com/products/va10820-radiation-harden...
Still subject to the same engineering constraints, but significantly less complex.
AFAIK the lower cost VORAGO designs require far less retooling so they're a lot cheaper with existing processes.
1) The yield rates for spaceflight-qualified chips is very, very low. Like 1%-5% or so. The chips are inspected when they come out of fab, and only the most perfect ones are given a spaceflight certification. The rest of the chips are used for other, less stringent applications (test boards, or military/embedded applications).
2) Spaceflight parts have significant paper trails. For metal parts, they are traced from the moment a lot of material comes out of the mill, and every time it is touched or changes hands thereafter that fact is recorded. Same thing with chips. Every chip has a "traveler" associated with it that records when it was manufactured, how it was stored, etc. Keeping those records costs a surprising amount of money. Handling the parts so the paper trail can be kept costs even more. You have to organize your logistics train such that every part is individually trackable. That reduces efficiency and adds cost.
3) Relatively low economies of scale.
You would never want a part involved in a stress test to be reused, and you certainly don't want test parts anywhere near a production craft. This isn't like IT where you can cannibalize parts from a QA box to put into a production server.
Also, the paper trail is quite literally paper. Its kinda amazing how slow the aviation industry is to adopt new things
I was thinking more of physical components, like an aluminum bracket, and you don't want a part with metal fatigue being installed as new.
I'm not sure about the RAD6000 being discussed here, but its successor, the RAD750, is fabbed with silicon-on-sapphire to help with total ionizing dose. For single event upsets, there is triple modular redundancy for all logic in the CPU.
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.
The closest thing I can remember encountering to what you describe is the "Contracrostipunctus" chapter in Douglas Hofstadter's Godel, Escher, Bach, where he writes a dialog featuring record players as an analogy to Godel's Incompleteness Theorem (which only applies to "formal systems" - descriptive mathematical languages). He does go on to explore a real-world example of the principle in the form of viruses - a cell cannot fully defend against DNA modification using only instructions found in its DNA. The same principle applies to cracking copy protection in games - no matter how elaborate the validity checks, there's always a single point of failure in the form of the final decision - "if(checks_pass){run_game()}" - which can be trivially short circuited with a debugger.
I'm not a good enough mathematician to fully understand the limits of Godel's Theorem. But it seems to me that all of the above applications are examples of some sort of well defined formal computational system, and you can't generalize it to "everything has a single point of failure" without some carefully defined rules as to what constitutes the boundaries of system.
http://www.math.yorku.ca/Who/Faculty/Brettler/3500_06/Godels...
To argue otherwise is to imply that all designs and all systems are equally robust, which is clearly not true.
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...
Kudos to all those who contributed to make this such an overwhelming success.
Science FTW.
Edit: Or rather should I say it’s relative... (lol?)
or the discovery of the Caesium-133 atom?
Counting minutes obviously came first as devices likes hourglass and water clocks are old (2000 BCE).
Regarding their precision, I got interested and per this paper [1] and the wikipedia page about traditional Chinese timekeeping [2], water clocks from two millennia ago might have around 15min precision.
For second level precision, it seems modern mechanical clocks were required, and they only precede the discovery of caesium by a few centuries.
[1] https://www.cambridge.org/core/services/aop-cambridge-core/c... [2] https://en.m.wikipedia.org/wiki/Traditional_Chinese_timekeep...
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".
https://www.nist.gov/news-events/news/2018/11/historic-vote-...
I think most of us will be observing the minute of silence from Earth, either way ;)
Same thing happened with Cassini. It's kinda poetic to see these outposts of Humanity's reach fade out after a sublime performance.
Also, there's a great documentary TV series called "7 Days Out" on Netflix which covers the last week of the Cassini mission.
* Lots of sensors
* Lots of communcation equipment
* No external controls
* Parts built without maitenance access
* Solar power
* Found on a mostly empty planet, with only a few other rovers around
* A planet next door littered with similar technology
A cooper wire around a iron core makes a good electromagnet. Deducing from there that it is a motor is not difficult. (It's even connected to the wheels.)
I'm not sure about the battery. I guess it's guessable because it has some unusual metals.
The lens (a clear piece of glass, thin, with a rounded surfaces) are also probably universal. If you have a few of them in line connected with moving parts with gears will confirm that it's the zoom of the camera.
Probably at the end of the camera is the sensor, I don't know how long it will keep the photo sensibility. It is connected by wires with the big chunk of wires and weird electric parts, so it must be the main board. The main board is also connected to the motors of the wheels.
The high gain antena is not parabolic (IIUC), it would have been an easy task to recognize it if it were parabolic :( . The low gain antena is a stick. By this time they already know the technology level of the motors and they will deduce that the communication is electromagnetic waves. So a big metal stick connected to wires is a good low gain antena candidate. The other weird thing has similar conections. And is orientable (they can see the inner gears of the support arm) and perhaps if you open it the inner structure also help. They will deduce that it is another antena.
[I personally think that for long distance transmission (specially in space) the electromagnetic waves are irremplazable. They may have a better encoding and filtering methods, but I guess they will mainly use electromagnetic waves.]
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.
edit: found a paper on the topic https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700...
also: https://arstechnica.com/science/2016/04/spacex-has-already-d...
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.
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.
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.
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.
Pinging a mars rover would be one hell of a DX, even if Opportunity won't be sending you a QSL card.
https://security.stackexchange.com/questions/18225/mars-curi...
I get the argument for why nuclear weapons aren't physically locked -- there's always people guarding them -- but not having security on a remotely operated billion-dollar device seems crazy to me, even if the technical barriers to establishing a link are high.
The thinking used to be that a 70m radio dish (and all the accompanying deep knowledge about pointing, relative velocity, channel codes, etc.) would be enough of an obstacle.
This thinking has definitively changed in the meantime.
[1]: https://sourceforge.net/projects/ion-dtn/files/ion-3.6.2.tar...
The idea that we send a robot to another planet and it drives around for that long still astounds me.
Thanks Opportunity, for all the knowledge you gave us. Thanks for the amazing pictures you sent us. Rest in Peace.
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.
(It's about Spirit, not Opportunity, but still).
(fan made) https://i.imgur.com/VbKV9DF.jpg
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.
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.
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.
Turns out the panels clean themselves with enough wind.
At the time the MER vehicles were built we knew enough about Martian dust to know that it would be a severe limiting factor on solar powered vehicles, but we didn't have enough experience with long lived solar powered vehicles to know all the details. We didn't know about "cleaning events" which were too irregular to fully plan for anyway. Ultimately, we got lucky, and we were able to take advantage of that luck on the fly. For example, we found that even with heavy dust accumulation the rovers could survive with careful power management during Summer, and during Winter we could conveniently park them on a South facing incline to maximize power.
Nevertheless, it is telling that for both rovers the thing that did them in was the thing that was always expected to limit their longevity: solar power generation. Spirit had a wheel get stuck and then couldn't park at a good angle during winter, and the absence of cleaning events during that time resulted in power generation falling below a critical threshold at that time. Opportunity got done in by an epic planet wide dust storm, which blocked sunlight long enough for the batteries to run out and for the vehicle to get dangerously cold (likely resulting in critical equipment failures).
Before we had that experience we had no idea that these things were possible, and nobody in their right mind would have bet money that the rovers would have been able to survive for years on Mars.
"If you had the opportunity to bring a hundred and eighty kilograms of stuff back from the surface of Mars, the last thing I wanna bring is something I know exactly what is made of."
Opportunity did her mission amazingly and is resting in peace in the place where she was designed to be.
We learned a lot from her and her sister mission, now, the effort is better spent building over their shoulders.
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?
i was responding to the assertion that humans are more 'up to task' for space exploration
> Also, how would AI help with the time lag?
giving the robots some autonomy to navigate / build between commands would speed up their mission and making up for the 15 minutes delay
Manned missions still make sense for two reasons: 1) humans are (presently) more versatile than computers/robots, and this will probably continue to be the case for 20+ years (although one human can do the work of many through technological augmentation), and 2) the emotional/sociological/etc. value of humans actually being there (plus in the longer term, actual settlement).
I'd like to be approximately the 1000th person to move to Mars, sometime in the next 15-30 years.
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.