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"I don't see any reason why someone shouldn't make this." You are exactly the kind of person that should build your own lander if you don't see this. And pleas

by natep 14y ago

"I don't see any reason why someone shouldn't make this." You are exactly the kind of person that should build your own lander if you don't see this. And please, stop asking all of these questions in bad faith. I applaud deeringc for engaging with your specific points, but I can't bring myself to do this, since it seems to me like you assume all aerospace engineers are uncreative drones that can't think outside the box and see the obvious solution you've reached from your armchair. Have you ever built a multiply-redundant, space-worthy, swarm-based system before? Have you built something that's any one of those three? If not, I don't have a problem with you thinking about them, but I do have a problem with your attitude. Edit: to clarify, I mean the attitude that comes across from your writing style. I have no idea what your qualificaitons are, how much thought you've put into this, how receptive you are to the idea that you're wrong, whether or not you recognize that everyone has more "unknown unkowns" than anything else, or what your actual attitude is. All I have are the words you write here. And my natural response to snark is more snark. And if you think you're the first person to think "wouldn't it be great if not every spacecraft didn't have to have to re-solve the problem of power, communications, and computation?" I first heard the idea proposed in a 2009 talk[1] by someone who has been an insider for over 20 years. Some gems I remember from that talk: * Having an identical copy is not redundancy * Complexity is inherently more succeptable to failures * Cars have been widely successful because of gas stations and repair shops. Spacecraft have to drag around their own * We could create a ring of satellites, each dedicated to providing comms to earth, wireless power, computing power, or whatever. Users of the system would just need to build a structure, interfacing components, and their instrument and launch it into a nearby orbit. [1] Abstract: http://www.spacecraftresearch.com/files/Fleeter.pdf http://www.spacecraftresearch.com/files/Fleeter.pdf

todayiamme 14y ago
> You are exactly the kind of person that should build your own lander if you don't see this. Once I have the financial resources, I actually plan to do so. > Have you built something that's any one of those three? To answer that yes I have, which is a completely orthogonal fact to my original comment because I am advocating reducing the qualifications of "space-worthiness" through the use of multiple copies. After reading your comment I decided that there had to be some respectable source who had advocated this earlier at some point and with some research I found this paper written by Rodney Brooks called Fast, Cheap and Out of Control : A robot invasion of the solar system outlining the same concept; http://people.csail.mit.edu/brooks/papers/fast-cheap.pdf http://people.csail.mit.edu/brooks/papers/fast-cheap.pdf > I mean the attitude that comes across from your writing style. Yes, I agree that my comments could look snarky under the weight of your assumptions, but I was doing my best to be genuine and engage in an honest discussion > I have no idea what your qualificaitons are, how much thought you've put into this, how receptive you are to the idea that you're wrong I'm actually quite certain that I'm wrong most of the times, but I don't know how I'm wrong and discussing, building things are the only ways to find out. > whether or not you recognize that everyone has more "unknown unkowns" than anything else Yes I do and it is a terrifying thought. > or what your actual attitude is. I'm doing my best to learn as much as I can and to never judge. (judgement takes up too many mental resources) > And if you think you're the first person to think "wouldn't it be great if not every spacecraft didn't have to have to re-solve the problem of power, communications, and computation?" I'm not and I would love to do more than just think and actually build things. > * Having an identical copy is not redundancy Can you please explain why? Is it because the failure points remain the same?
- natep 14y ago
  Hey, I'm glad you responded, and that I misinterpreted where you were coming from and your intentions, but I guess that happens when limited to text (not that a misunderstanding-free medium exists). But as you've probably gathered by now, most of my response came from reading "I don't see any reason why someone shouldn't make this. [and I doubt a good one exists]" instead of "I don't see any reason why someone shouldn't make this. [and I would like to hear some]" > Fast, Cheap, and Out of Control The first thing that popped into my head when I saw this title was NASA's "Faster, Better, Cheaper" initiative. I will admit that I do not know much about it, but what I do know is that there were some failures (as you would expect) and the public did not react well. The failures did not come from not having space-grade parts, IIRC, but for various other reasons. The most infamous was the Mars Climate Orbiter, known for failing due to an imperial-metric conversion error [1], that is still brought up in almost every space-exploration piece that gets sufficient attention. Anecdotally, the lessons learned by those I've talked to are (1) choose 2 and (2) the public will not tolerate failure on large NASA projects, even if those projects cost a fraction of what it takes to host an Olympics, or to buy Instagram, or fight a war for a day.[2] But I have just now hopefully started a discussion with my coworkers about this paper[3] on our message board. So anyways, about the paper. It looks like your idea is only mentioned briefly in the one section, and not fleshed out. The idea was somewhat more fleshed out in the talk I went to. What I meant by my line of questioning was that I haven't seen an implementation of these concepts outside academia, even though the idea has been around for some time, and the industry isn't entirely driven by irrational beings, so there must be some technical reasons why the ideas haven't been fully adopted. >> * Having an identical copy is not redundancy > Is it because the failure points remain the same? Essentially, yes. His argument that most failures were systematic, and not due to unequal 'wear' of various kinds. Software especially, since on space missions it is implemented to be as deterministic as possible. That means that even if the primary processor fails gracefully due to bad internal logic, and a hot backup immediately takes its place, the backup will behave in exactly the same way given those inputs, which are likely to stay the roughly the same across the switch. Another example is a mission where the high gain antenna succumbed to a systematic failure, and they completed the mission on its low gain antenna. If there had been 2 identical antennas, they would not have been able to. Designing and testing components to last a long time under the conditions you expect and test for is relatively easy. It's when the designs and tests don't match reality is when the problems happen. If you write something and make a copy, it will retain all of the typose of the original, and it's the same with Code/CAD/etc (and you might be more likely to introduce bugs than fix them). Ground-based systems can get away with this because of how easy it is to replace/repair broken units in a redundant setup. [1] Even though it was due to a much larger issue related to how the project was carried out, and just happened to manifest in that error. It could have easily been a kilometer/meter mixup instead. And having a backup string of landing hardware/software wouldn't have helped in this case, unless the backup units had a different design/implementation. [2] And yet, JPL still chose to use the skycrane. Very couragous. [3] http://www.dau.mil/pubscats/ATL%20Docs/Mar-Apr10/ward_mar-apr10.pdf http://www.dau.mil/pubscats/ATL%20Docs/Mar-Apr10/ward_mar-ap...

by natep 14y ago

todayiamme 14y ago

> You are exactly the kind of person that should build your own lander if you don't see this. Once I have the financial resources, I actually plan to do so. > Have you built something that's any one of those three? To answer that yes I have, which is a completely orthogonal fact to my original comment because I am advocating reducing the qualifications of "space-worthiness" through the use of multiple copies. After reading your comment I decided that there had to be some respectable source who had advocated this earlier at some point and with some research I found this paper written by Rodney Brooks called Fast, Cheap and Out of Control : A robot invasion of the solar system outlining the same concept; http://people.csail.mit.edu/brooks/papers/fast-cheap.pdf http://people.csail.mit.edu/brooks/papers/fast-cheap.pdf > I mean the attitude that comes across from your writing style. Yes, I agree that my comments could look snarky under the weight of your assumptions, but I was doing my best to be genuine and engage in an honest discussion > I have no idea what your qualificaitons are, how much thought you've put into this, how receptive you are to the idea that you're wrong I'm actually quite certain that I'm wrong most of the times, but I don't know how I'm wrong and discussing, building things are the only ways to find out. > whether or not you recognize that everyone has more "unknown unkowns" than anything else Yes I do and it is a terrifying thought. > or what your actual attitude is. I'm doing my best to learn as much as I can and to never judge. (judgement takes up too many mental resources) > And if you think you're the first person to think "wouldn't it be great if not every spacecraft didn't have to have to re-solve the problem of power, communications, and computation?" I'm not and I would love to do more than just think and actually build things. > * Having an identical copy is not redundancy Can you please explain why? Is it because the failure points remain the same?

natep 14y ago
Hey, I'm glad you responded, and that I misinterpreted where you were coming from and your intentions, but I guess that happens when limited to text (not that a misunderstanding-free medium exists). But as you've probably gathered by now, most of my response came from reading "I don't see any reason why someone shouldn't make this. [and I doubt a good one exists]" instead of "I don't see any reason why someone shouldn't make this. [and I would like to hear some]" > Fast, Cheap, and Out of Control The first thing that popped into my head when I saw this title was NASA's "Faster, Better, Cheaper" initiative. I will admit that I do not know much about it, but what I do know is that there were some failures (as you would expect) and the public did not react well. The failures did not come from not having space-grade parts, IIRC, but for various other reasons. The most infamous was the Mars Climate Orbiter, known for failing due to an imperial-metric conversion error [1], that is still brought up in almost every space-exploration piece that gets sufficient attention. Anecdotally, the lessons learned by those I've talked to are (1) choose 2 and (2) the public will not tolerate failure on large NASA projects, even if those projects cost a fraction of what it takes to host an Olympics, or to buy Instagram, or fight a war for a day.[2] But I have just now hopefully started a discussion with my coworkers about this paper[3] on our message board. So anyways, about the paper. It looks like your idea is only mentioned briefly in the one section, and not fleshed out. The idea was somewhat more fleshed out in the talk I went to. What I meant by my line of questioning was that I haven't seen an implementation of these concepts outside academia, even though the idea has been around for some time, and the industry isn't entirely driven by irrational beings, so there must be some technical reasons why the ideas haven't been fully adopted. >> * Having an identical copy is not redundancy > Is it because the failure points remain the same? Essentially, yes. His argument that most failures were systematic, and not due to unequal 'wear' of various kinds. Software especially, since on space missions it is implemented to be as deterministic as possible. That means that even if the primary processor fails gracefully due to bad internal logic, and a hot backup immediately takes its place, the backup will behave in exactly the same way given those inputs, which are likely to stay the roughly the same across the switch. Another example is a mission where the high gain antenna succumbed to a systematic failure, and they completed the mission on its low gain antenna. If there had been 2 identical antennas, they would not have been able to. Designing and testing components to last a long time under the conditions you expect and test for is relatively easy. It's when the designs and tests don't match reality is when the problems happen. If you write something and make a copy, it will retain all of the typose of the original, and it's the same with Code/CAD/etc (and you might be more likely to introduce bugs than fix them). Ground-based systems can get away with this because of how easy it is to replace/repair broken units in a redundant setup. [1] Even though it was due to a much larger issue related to how the project was carried out, and just happened to manifest in that error. It could have easily been a kilometer/meter mixup instead. And having a backup string of landing hardware/software wouldn't have helped in this case, unless the backup units had a different design/implementation. [2] And yet, JPL still chose to use the skycrane. Very couragous. [3] http://www.dau.mil/pubscats/ATL%20Docs/Mar-Apr10/ward_mar-apr10.pdf http://www.dau.mil/pubscats/ATL%20Docs/Mar-Apr10/ward_mar-ap...