Slashdot Mirror
Probe Crash Due to Misdesigned Deceleration Sensor
squirrelhack writes "Seems as though the Genesis spacecraft was able to launch from earth, travel through space, avoid aliens, and cruise back into the atmosphere to be caught by stunt pilots waiting patiently with their helicopters. Alas, the brakes didn't work because a sensor was designed upside down.
... that human error can happen even in the most expensive projects.
This signature was left intentionally blank.
I wish POLITICIANS would stop judging accidents with NASA and spaceflight in general as "wastes".
It's NOT a waste. Research REQUIRES failure. SUCESS requires failure.
One step at a time, my fellow scientists and engineers. One step at a time.
Reply or e-mail; don't vaguely moderate. Ex-O'Reilly/MIT employee, now a full-time Google employee.
All of life is really like that. The only reason space mission failures are so spectacular is because everything is a one-of, and any mistake turns great success into a crater. The fact that these failures are the exception and not the norm is a testement to the expertise of all involved. It's their great skill that has allowed us to become so jaded :).
All it takes is one ass-umption to make the great space systems contractor to look like an ass.
Of course, they usually do get it right, in near-heroic fashion. But didn't it occur to anyone to try this out by, say, building a unit without the science part, bringing it along on a pre-scheduled Shuttle flight, and de-orbiting it? (IIRC, design and test pre-dated the Coulmbia accident). That way, they get a real re-entry at low (for NASA) cost.
The clearance system sounds logical. It is not. It is completely arbitrary. -- John Bolton
Isn't this the same situation that resulted in the creation of Murphy's Law. They were doing acceleration tests on humans but they installed the sensors backwards so the tests were useless.
The original lesson they learned was: That if a design allows for a part to be installed incorrectly, then that part will be installed incorrectly (eventually, or maybe even the first time).
Just a little bit of history repeating.
Sheeeeezzzz...
These kind of mistakes make me wonder. WHY does NASA *HAVE* to re-design every freakin' thing on every freakin' mission from the ground up every freakin' time?
We're flying alpha-test spacecraft.
Re-usable modules anybody?? Heard of those? Standard designs? Sure, some parts are going to be different, namely the actual scientific instruments, but fer ghodssake an accelerometer?! WhyTF do we need to redesign that (its a weight, a spring and a switch, fer the love of pete) ?!!
-sigh-
-- -- The Dragon De Monsyne
But we know things like this already. Failure is fine if you learn from it.
What did we learn? Um... accelerometers only work in one direction... if you install them backwards, things don't happen right!
We tolerate mistakes if we have to make them, but this one (like all the recent Lockheed Martin screwups on work for NASA) appears to be stupidity.
-- IANAEG - I am not an elder god.
Just like you should never write that code that cannot be tested (in the perfect world, every line would be executed during testing), you should never design a subassembly that cannot be tested.
It's a organizational attitude adjustment that's needed to put this into effect.
I remember reading about an Apollo moon car issue where a core-sample clamp would not work because it was installed upside down. It ended up wasting about an hour of astronaut time. Parts designers should avoid symmetrical designs where things fit, or semi-fit, if misoriented. Design them with things sticking out so that it would not fit *at all* if put in wrong.
Table-ized A.I.
you probably also suggest that there is...
;-)
no such thing as cold, just the absence of heat
no such thing as dark, just the absence of light
guess what?
we english speaking humans have decided to call
and the absence of heat, 'cold'
the absence of light, 'dark'
and negative acceleration, 'deceleration'
You can look up what we call things here
Murphy's law was a quote (people can argue about who said it first) directly related to accelerometers/strain guages and whether or not they could be connected backwards ...
"Flame away, I wear asbestos underwear"
Campain contributions?
besides, we might find a use for it someday. Radioisotopes don't grow on trees...
We've all made mistakes like this, I think. Somehow, you just get things backwards in your head once, and then fix it as a `definite truth' which you don't bother to look at again.
Usually, I find these kinds of mistake in my own work when someone else, who hasn't been tainted in the same way, points it out to me. I wonder why this kind of peer review didn't happen here?
colonization of mars does not seem possible because the body does not rotate on it's axis.
1. What the hell are you talking about? Mars rotates just fine, and even has seasons.
how is this problem to be overcome when you must grow plants to sustain your existance?
2. Maybe the same way we do it on Earth? High powered, wide spectrum lamps.
Javascript + Nintendo DSi = DSiCade
No, bad idea! Have you never seen Superman III? It'll become an evil super-villain.
I still have more fans than freaks. WTF is wrong with you people?
One of the principles that has come about from continuous improvement, kanban, Toyota manufacturing is the idea of poke-a-yoke, or poka-yoke engineering.
The idea is, you design something so that it can only be used one way, so that errors in installation are eliminated. For example, if this switch/sensor/whatever needed to be installed from one side, you put a bump/notch on the opposite side that would prevent the part from being installed wrong.
For another example of this, if you have an N64 gaming system, take apart one of the controllers and look at the button design. Every button has slots that it fits in, so that you can only install a button in one location. There's no worrying about "Did I swap the A and B buttons?" because it's not possible.
Overrated / Underrated : Moderation
...and that depends on your frame of reference. Going from 1000kph to zero is speeding up in as many frames of reference as it is slowing down, just not in ours.