Domain: ralentz.com
Stories and comments across the archive that link to ralentz.com.
Comments · 27
-
Re:Planet hunting is nice-
I'd be happier if nasa, and those who do real science,
I think Richard Feynman would object to that statement
-
Re:Liability
Astronauts are not suicidal. If you really want to know about this, read Feynman's appendix to the Roger's Commission report. Management was lying and they had a whole process built so that they did not even know they were lying.
-
politics != science
Proving once again (as if proof were needed) that science and politics are the worst possible companions. Read the Feynman Report on the Challenger disaster ( http://www.ralentz.com/old/space/feynman-report.html [among many others]) where he lambasts NASA decision makers for using politics-inspired wishful thinking instead of science to decide to launch over strenuous objections by staff scientists and engineers. This meme is seen throughout history as the politics of wishful thinking crash onto the iceberg of reality time and again.
-
Feynman Shuttle ReportThis sounds uncomfortably similar to Feynman's criticism of the "top-down" method of constructing the Space Shuttle.
The Space Shuttle Main Engine was handled in a different manner, top down, we might say. The engine was designed and put together all at once with relatively little detailed preliminary study of the material and components. Then when troubles are found in the bearings, turbine blades, coolant pipes, etc., it is more expensive and difficult to discover the causes and make changes. For example, cracks have been found in the turbine blades of the high pressure oxygen turbopump. Are they caused by flaws in the material, the effect of the oxygen atmosphere on the properties of the material, the thermal stresses of startup or shutdown, the vibration and stresses of steady running, or mainly at some resonance at certain speeds, etc.? How long can we run from crack initiation to crack failure, and how does this depend on power level? Using the completed engine as a test bed to resolve such questions is extremely expensive. One does not wish to lose an entire engine in order to find out where and how failure occurs. Yet, an accurate knowledge of this information is essential to acquire a confidence in the engine reliability in use. Without detailed understanding, confidence can not be attained. A further disadvantage of the top-down method is that, if an understanding of a fault is obtained, a simple fix, such as a new shape for the turbine housing, may be impossible to implement without a redesign of the entire engine.
Full report is here http://www.ralentz.com/old/space/feynman-report.html
-
What is the opposite of insightful?
You raise an issue worthy of further consideration. It was first posed succinctly by the fictional character from Austin Powers - International Man of Mystery. Dr. Evil: "Why must I be surrounded by frickin' idiots?" (Similarly, Scott Adams states this as the Dilbert Principle, we are all stupid, about most things, most of the time.) With the rise of civilization and technology has come increased complexity. Unfortunately, we seem, on average, to be ill equipped to cope with it. It's amazing we can get things done at all, really, when you think about the difficulty we have making what ought to be simple decisions.
Consider this week the news is full of European countries enacting substantial budget cuts. We know that's the wrong thing to do. It times of economic prosperity, we should run balanced budgets or pay down national debt. When faced with a recession so enormous that people invoke the Great Depression as an analog, though we have only about 20% unemployment, rather than 30% or more, this situation is dire. We know that we must run deficits, large ones, in order to create a demand stimulus large enough to moderate this trough of the economic cycle. Nonetheless, we have politicians trying to score political points by railing against deficit spending -- which didn't bother them for the past 8 years when they were in charge.
The problem is profound, widespread ignorance, but not merely ignorance as in the mere unawareness of relevant facts. It's ignorance that makes one blind to the limits of one's own ability to asses one's own capability. Smearing lemon juice on your face doesn't make you invisible to security cameras. If you think it does, then you're not qualified to be a bank robber, but you're also not qualified to assess many, many other issues -- foremost among them, you're not qualified to assess your sills as a bank robber, and are likely to be utterly ignorant as to the possibility that you might not be able to assess those skills without outside assistance. Presented with relevant facts, these people remain impervious to rational assessment of a situation. They are so poorly equipped that they can't evaluate their own ignorance.
The Anosognosic's Dilemma: Something's Wrong but You'll Never Know What It Is (Part 1)
After the first disaster which destroyed a Space Shuttle and killed all the astronauts aboard, a presidential commission was appointed to investigate, by President Reagan. Its members included the nobel prize winning physicist, Richard Feynman. Feynman wrote his own appendix to the official report of the committee. It's one of the most fascinating documents, and should be required reading for any engineer, politician, manager, or judge . It ranks up there with The Selfish Gene, Goedel Escher, Bach, and The Mythical Man Month.
Richard Feynman, the Challenger Disaster, and Software Engineering
Feynman's Appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident
The lesson of the Challenger disaster directly applies to the Deepwater Horizon oil well blowout disaster. Simply because we haven't had a disaster yet does not in any way imply that we are not doing things, lots of things, which are likely to lead to a disaster.
This problem applies to big problems, like managing national budgets, building and flying reusable spacecraft, drilling a mile under the ocean surface for oil -- and to small problems, like using mod points on Slashdot. -
NASA Statistics
Now the real question: Has their statistical methodology improved in the last 20 years? Is NASA any less of a PR whore than it was back then?
http://www.ralentz.com/old/space/feynman-report.html -
The Mac Programming Works C Compiler......had the best error messages.
"...And the lord said, `lo, there shall only be case or default labels inside a switch statement'"
"a typedef name was a complete surprise to me at this point in your program"
"`Volatile' and `Register' are not miscible"
"This struct already has a perfectly good definition"
"Symbol table full - fatal heap error; please go buy a RAM upgrade from your local Apple dealer"
"type in (cast) must be scalar; ANSI 3.3.4; page 39, lines 10-11 (I know you don't care, I'm just trying to annoy you)"
...and more. -
Re:Contamination
You should really read physicist Richard Feynman's report on the Challenger disaster for an honest analysis of what lead to that orbiter's destruction. There's also a good list of myths about the disaster that's worth reading - for example the belief that Reagan's state of the union had anything to do with the disaster.
Launch officials clearly felt pressure to get the mission off after repeated delays, and they were embarrassed by repeated mockery on the television news of previous scrubs, but the driving factor in their minds seems to have been two shuttle-launched planetary probes. The first ever probes of this kind, they had an unmovable launch window just four months in the future. The persistent rumor that the White House had ordered the flight to proceed in order to spice up President Reagan's scheduled State of the Union address seems based on political motivations, not any direct testimony or other first-hand evidence. Feynman personally checked out the rumor and never found any substantiation. If Challenger's flight had gone according to plan, the crew would have been asleep at the time of Reagan's speech, and no communications links had been set up.
Feynman's Appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident
-
Re:IBM == GODS OF VIRTUALIZATION
Cool.
I'm sure IBM is not showing us everything, (wink, wink) what they do for the DoD, NSA and the rest of the alphabet, I'm sure would give us nightmares.
(Laboratory for Telecommunications Sciences (LTS) -programs continue to emphasize transmission of quantum communications through optical elements.
Quantum communications, quality of service, and high- speed network interfaces)
http://www.er.doe.gov/ascr/NITRD05supplement.pdf
August 19, 2002
IBM, RIM Drafted By Defense Department
http://www.internetnews.com/ent-news/article.php/1 448711
"Big Blue Monday said its AIX 5L was the first UNIX operating system certified by the DoD to run COE Version 4 (Common Operating Environment), a user interface which utilizes the same commands regardless of what operating system is running on the server."
Fun huh?
VMware: US military staff and do not recommend VMware for secure environment:
http://www.cs.nps.navy.mil/people/faculty/irvine/p ublications/2000/VMM-usenix00-0611.pdf
Apple's foray in DOS add-on cards
http://docs.info.apple.com/article.html?artnum=112 244
http://en.wikipedia.org/wiki/Quadra_610
http://www.ralentz.com/old/mac/faqs/source/houdini .html
http://homepage.mac.com/olivers/DOScard/DOScard.ht ml
http://lowendmac.com/archive/06/0407.html -
Re:A rational option
Nothing is "safe" - but how we judge the odds and risks affects our expectations. The Space Shuttle was planned with an expected hull loss failure rate of about 1 in 10,000, when operational experience and the judgement of the engineers indicated about 1 in 100. If you wish to have a technology that is accepted and utilized properly, the risks have to be judged correctly, not sold like a cure-all. Read the Rodgers Report for more information:
http://www.ralentz.com/old/space/feynman-report.ht ml
In addition, when you depart the ground in a 747, you may have up to 500,000 lbs. of a highly energetic fuel along for the ride, yet the hull loss rate on 747s is less than 1 per 1,000,000 departures. The presence of explosive material alone does not indicate the risk level. Commercial aviation is the beneficiary of decades of engineering experience, stringent safety regulation, and a culture that encourages disclosure of risk vs. burying the messenger and hoping the probabilities don't catch up on your watch.
So, to be more precise, the political process is more likely to generate safety estimates off by orders of magnitude (in order to sell the product), and then when those fail to come true (not through the fault of the technology, but the way it was used), the whole technology could be needlessly scrapped for decades.... like nuclear power was in the U.S. after the Three Mile Island incident. I was expressing the hope that we would be slightly wiser this time around in deploying a very costly but potentially very beneficial technology, and the most likely obstacles to it. -
Most interesting reportThe most fascinating report on the Challenger disaster remains Richard Feynman's dissent on the official line of the Rogers Report (on whose committee he served). Read it here.
"If a reasonable launch schedule is to be maintained, engineering often cannot be done fast enough to keep up with the expectations of originally conservative certification criteria designed to guarantee a very safe vehicle. In these situations, subtly, and often with apparently logical arguments, the criteria are altered so that flights may still be certified in time. They therefore fly in a relatively unsafe condition, with a chance of failure of the order of a percent (it is difficult to be more accurate).
Whether you consider that "political interference" is a different matter.
Official management, on the other hand, claims to believe the probability of failure is a thousand times less. One reason for this may be an attempt to assure the government of NASA perfection and success in order to ensure the supply of funds. The other may be that they sincerely believed it to be true, demonstrating an almost incredible lack of communication between themselves and their working engineers." -
Re:A brutal dictatorship put first man in spaceDon't forget a blatant disregard for safety and human life, that certainly made things easier.
So, NASA has a perfect safety record? The testimony of Richard Feynmann http://www.ralentz.com/old/space/feynman-report.h
t ml alone was enough to convice me that they're less than sterling in this regard. -
Shuttle Engines Not Engineered Properly
As Richard Feynman's brilliant analysis from 1986 clearly states, the shuttle's main engines were NOT designed properly and are doomed to be both expensive to maintain and markedly dangerous to use.
A link to his comments is at http://www.ralentz.com/old/space/feynman-report.ht ml
He has a wonderful explanation, in terms that non-engineers as well as engineers can understand, about how to build complex devices. Good engineering, he says, comes from dividing the task in to component parts, creating specifications for those parts, building samples, testing them to their limits, retesting them to various other limits, until you have a complete understanding of all the failure modes of that component, as well as the reliability of your manufacturing process for that component. Then, you assemble multiple components together and test that assembly together in all the modes you can conjure up, to create what I have always heard termed, "A Well-characterized System".
As he points out, the space shuttle main engines (SSME's), though complex and "groundbreaking" in the sense that they were very big and incorporating some (at the time) quite advanced technologies, they were NOT WELL CHARACTERIZED on a component basis. To my knowledge (although I'm not a NASA watcher with as much fervor as some) I don't believe the SSMEs have EVER BEEN analyzed and re-engineered to create characterizations of their failure points, reliability, etc.
The fact that NASA's next plan is to use them in the follow-on vehicles for heavy lift only testifies to NASA's complete lack of focus here. They should put out several contracts for heavy lift engines with well-characterized failure modes, with focuses on reusability, reliability, maintenance cost, and overall operating cost.
We're soon going to be stuck with the next-gen heavy lift using components of unknown reliability, which forces us to replace component parts ("tune-up" or "overhaul") the system too often and with too large an expense.
Feynman was right. Solve the root cause. Engineer these things with good methodologies. And don't tie us down to next-gen-of-schlock-engineering if we don't have to be. I congratulate the able engineers who worked on the SSME's, but I respect Feynman's analysis that correct procedures benefit lowering long-term costs and ensure safety of the admirable crews who pilot our national spacecraft. -
Re:"Pilot"Despite outlineblue's inability to communicate in a civilized manner, it looks like you didn't fact-check your source. Here's a link to Feynman's appendix to the Roger's Report. The relevant section:
The computer system is very elaborate, having over 250,000 lines of code. It is responsible, among many other things, for the automatic control of the entire ascent to orbit, and for the descent until well into the atmosphere (below Mach 1) once one button is pushed deciding the landing site desired. It would be possible to make the entire landing automatically (except that the landing gear lowering signal is expressly left out of computer control, and must be provided by the pilot, ostensibly for safety reasons) but such an entirely automatic landing is probably not as safe as a pilot controlled landing.
It looks like your second-hand source probably misquoted the first part of this paragraph.
Your other problem is Feynman has been dead since 1988. So anything he said is likely to be out of date. For example:There is not enough room in the memory of the main line computers for all the programs of ascent, descent, and payload programs in flight, so the memory is loaded about four time from tapes, by the astronauts.
It's possible they're still using that computer system, but there's a good chance they've progressed.
Because of the enormous effort required to replace the software for such an elaborate system, and for checking a new system out, no change has been made to the hardware since the system began about fifteen years ago. The actual hardware is obsolete; for example, the memories are of the old ferrite core type. -
Re:Why so many?
That 2% failure rate, my friend, is a perceived failure rate, and the actual risk might be much higher than that. Space shuttles are such complex systems that it is impossible to test every single aspect of it. Most of the time, we test it until we FEEL that it is safe to launch. The only reason why we haven't had more accidents can only be attributed to luck. Read Richard Feynman's report on the challenger shuttle accident: http://www.ralentz.com/old/space/feynman-report.h
t ml -
Relevant Feynman Quote(1/50failure*2boosters=1/25)Here's what Feynman had to say back in 1986. In response to a comment I read about 1/50 meaning that we're unlikely to have another shuttle accident before the fleet is retired, remember that there's two SRBs, so 1/50 failure rate translates to 1/25. STS-51L (the doomed 1986 Challenger flight) was the 25th launch. See also the Gambler's Fallacy.
An estimate of the reliability of solid rockets was made by the range safety officer, by studying the experience of all previous rocket flights. Out of a total of nearly 2,900 flights, 121 failed (1 in 25). This includes, however, what may be called, early errors, rockets flown for the first few times in which design errors are discovered and fixed. A more reasonable figure for the mature rockets might be 1 in 50. With special care in the selection of parts and in inspection, a figure of below 1 in 100 might be achieved but 1 in 1,000 is probably not attainable with today's technology. (Since there are two rockets on the Shuttle, these rocket failure rates must be doubled to get Shuttle failure rates from Solid Rocket Booster failure.)
Feynman's Appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident -
Re:60%?
After reading Feynman's addendum to the Challenger commission report, I'm surprised this 60% figure wasn't interpreted as "a 40% margin of safety".
-
Re:NASA == NIH syndrome.
For those who don't recognize the quote, the exact wording is: "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." It comes from Richard Feynman's appendex to the Rogers Commission report on the Challenger.
-
Re:What is an acceptable risk?
Feynman
Spacecraft are not like airliners. They're not as safe. But people still use them; they're used less often than airliners, and they do more work when they are used.
But yes, the Space Shuttle does need to give way to newer and better spacecraft. If anyone still knows how to build them. Perhaps the Russians and Germans can help. -
Re:Shuttle software codersThis software got superb reviews from heroes of science long before Fast Company. Notably, Richard P Feynman, Richard Chace Tolman Professor of Theoretical Physics at the California Institute of Technology, noted in his appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident that the "computer software checking system and attitude is of the highest quality" and that "the attitude to system failure and reliability is not nearly as good as for the computer system." Interesting how it seems this has gotten them into trouble again.
Paul -
Re:Shuttle software codersThis software got superb reviews from heroes of science long before Fast Company. Notably, Richard P Feynman, Richard Chace Tolman Professor of Theoretical Physics at the California Institute of Technology, noted in his appendix to the Rogers Commission Report on the Space Shuttle Challenger Accident that the "computer software checking system and attitude is of the highest quality" and that "the attitude to system failure and reliability is not nearly as good as for the computer system." Interesting how it seems this has gotten them into trouble again.
Paul -
Re:How Independent an Investigation?
Feynman was flamboyant and made a great show of the O-ring problem in front of TV cameras, an unrehearsed and disruptive performance
I wouldn't call it flamboyant.You can watch a video of Feynman demonstrating the O-ring problem; he demonstrates the problem and describes it in a very matter-of-fact fashion. (Sorry for the link to a RealMedia file!)
Feynman's appendix to the Roger's Commission report on the Challenger disaster is a very interesting read. He makes the estimate that there is a 1 in 100 chance of a catastropic failure (pretty close, since the actual rate is now 2 in 107).
The appendix calls into question the management practices at NASA; I'm not sure how the agency has changed since then, but I am certain many of the points he makes are still highly relevant today. -
Funding is a secondary problemIt doesn't matter how much funding you pour into NASA if NASA consistently lies to itself.
For those of you too lazy to read the Feynman appendix, the key message Feynman added to the Challenger report was that the Challenger accident wasn't so much a result of the wrong kind of o-ring rubber as much as a result of NASA management's inability to hear the truth from its engineers and suppliers.
When an organization fosters dishonesty, as Feynman documented, you can pour trillions in and not get results.
-
And this is why it happened ...RFead the report at http://www.ralentz.com/old/space/feynman-report.h
t ml as to *WHY* it happened.Written by Feynman himself, and is an extremely good summary of how the engineers knew the safety was shit, but the managers didn't believe them. A great read.
You can all thank me later.
-
Link to Feynman report
An interesting read -- for those of you who haven't seen it is the Appendix written by Feynman to the Challenger Report (otherwise known as the Rogers Commission Report).
see http://www.ralentz.com/old/space/feynman-report.ht ml
or
http://www.fotuva.org/feynman/challenger-appendix. html -
Feynman and the sum over histories
The concept of a multiverse is not new, as many have pointed out. But what ARE all those other universes and why "are we in this one"? Quantum uncertainty has led to some interesting theories about divergent universes. Anyhow, Feynman has a theory referred to as the Sum Over Histories. It's actually more than a thoery, as it is apparently very predictive of quantum interactions and is fundamental to the field of Quantum Computing. Being a computer geek and not a physics geek, I find it interesting if thick. There's info about how it relates to the universe's formation here.
On a related note, Feynman's books (Surely you must be joking, Mr Feynman & What do you care what other people think?, are both insightful and very entertaining) -
"Banned from Argo"
"Banned from Argo" was written by Leslie Fish, who has given permission for her lyrics to be posted. I'm sure a search would find it....
... Yep. AltaVista, even.
The first dozen hits were to various of the many parodies. (There are so many parodies of this song that someone is putting together a song book called "Bastard Children of Argo". It's going to be ... large.)
However, this one is the original lyrics:
Argo lyrics on Robert Lentz's web page
(Hey, Robert, I posted your URL on Slashdot... INCOMING!!