Oops. Was it the Red Wire or the Blue?

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Turns out that this headline on Monday...

 

"European Vega rocket suffers major launch failure, satellites for Spain and France lost."

 

...was caused by wires which control the direction of thrusters being swapped. So when the thrusters should have moved 'out' they actually moved 'in'.

 

https://www.thelocal.es/20201118...

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Last Edited: Wed. Nov 18, 2020 - 01:21 PM
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If only there were some way to stop connectors being mated the wrong way around ...

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Gee, if only there had been a test case for that written out during the planning stage!

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"

 

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I knew they should not have hired that colour blind work experience kid...

Ross McKenzie ValuSoft Melbourne Australia

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Brian Fairchild wrote:
...was caused by wires which control the direction of thrusters being swapped. So when the thrusters should have moved 'out' they actually moved 'in'.
I've done this with the wires to aileron servos connecting to the wrong channels in the Rx of a model plane. This is why one does pre-flight checks to make sure the control surfaces move in the correct sense.

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clawson wrote:

I've done this with the wires to aileron servos connecting to the wrong channels in the Rx of a model plane. This is why one does pre-flight checks to make sure the control surfaces move in the correct sense.

 

Although with any Tx from the last twenty years it would be easier to reconfigure the servo movement in software, rather than take the wing off and swap the connectors ! I'm not sure whether that's progress or not ...

 

awneil wrote:

If only there were some way to stop connectors being mated the wrong way around ...

 

That's seem to be the 'key' part to the problem ...

 

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I seem to recall my last RC transmitter had sense reverse switches for most if not all the channels.

 

Neil

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Bet he feels pretty rotten right now  ...using them, indeed  cheeky

 

 

There was a similar thing on Apollo test flight, that "allowed" them to test the emergency escape rocket.    

The sudden drop in pressure was detected and caused a shutdown command to be issued. Unfortunately, the command signals for engine three were partially cross-wired with engine two, so that the shutdown of engine two caused a liquid oxygen valve for engine three to close, resulting in a shutdown of that engine as well.

 

a very interesting read to waste some time

https://www.drewexmachina.com/20...

 

I may have confused the launch escape event with another test--not sure which one, but on some test the escape fired unexpectedly & proved that it would work (maybe wasn't even Apollo)

 

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Wed. Nov 18, 2020 - 04:26 PM
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It's not so easy to test closed-loop rocket control systems on the ground.

And there are lots of opportunities for phasing errors during design and assembly.

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I remember a ham radio satellite that had a kick motor to push it into an elliptical orbit from its initial standard orbit, but the 8 bit timer wiring from the control unit to the motor control unit was reversed, so LSB became MSB

So when a short in orbit test firing was made, the burn was much longer then expected.  oops wrong orbit.  

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"