[amsat-bb] Re: Gospodin Murphy was right!

Greg D ko6th.greg at gmail.com
Sun Jul 21 13:30:34 PDT 2013


Except that not all of them were inverted, according to one report.

I also heard that on other rockets, these sorts of sensors can be tested 
by watching the rocket, mounted on the launch pad, move as the earth 
spins. This model sensor can't do that for some reason, and electrical 
tests, of course, would show everything is fine. So it wasn't until the 
rocket actually launched (by which time it was too late) that the error 
was detected.

But fundamentally, I believe a device whose sole purpose it is to 
indicate direction should have no possibility of being mounted in any 
direction other than the one intended. Either that, or there should be a 
calibration step in the process somewhere to correct for this. In fact, 
now that I think of it, it should be a relatively simple test to look at 
the sensors immediately (milliseconds) after launch to confirm the 
orientation of the sensors, and flip them logically if necessary.

Of course, changing flight software is a non-trivial task, as would a 
mechanical modification to key the sensor and mounting, so doing a video 
inspection of the sensors as the only remediation is not a surprise.

Greg KO6TH


Roger Kolakowski wrote:
> Maybe the un-assembled frame was oriented "nose" down when he 
> installed them...so "this side up" made sense...
>
> Roger
> WA1KAT
>
>
> On 07/21/2013 12:46 PM, Greg D. wrote:
>> A member of our radio club is familiar with the rocket, from some 
>> past work. He said that the sensors are not keyed, and the "This side 
>> up" label is in rather small print. Between that and Murphy, I wonder 
>> why this wasn't a more frequent occurrance...
>>
>> Greg. KO6TH
>>
>> Alan <wa4sca at gmail.com> wrote:
>>> An interesting article on the recent launch failure of a Proton-M:
>>>
>>> http://preview.tinyurl.com/kt5x9hw
>>>
>>> The latest in a long line of bizarre, expensive errors in the world
>>> launch business.
>>>
>>> 73s,
>>>
>>> Alan
>>> WA4SCA
>>>
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>> - Sent from my new toy; pls excuse tupos.
>> _______________________________________________
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>
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