Triboelectrification Questions? Try This.

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An earlier blog post attempted to answer questions about triboelectrification. Since there are still a few questions floating around we’re reposting it for those who missed it on the first go-round.

Enjoy.

Flight Rules and Triboelectrification (Whatthe Heck is That?)
 
The skies look clear except for some high clouds, there’s no rain in theimmediate forecast, so why might a rocket not launch? The answer is somethingcalled triboelectrification. While this isn’t a word you encounter every day,you might experience it if you walk across a dry carpet or brush up against acat and then touch a metal surface: it’s static.
 
In the case of Ares I-X, flying through high-level clouds can generate“P-static” (P for precipitation), which can create a corona of static aroundthe rocket that interferes with radio signals sent by or to the rocket. Thiswould create problems when the rocket tries to transmit data down to the groundor if the Range Safety Officer at Cape Canaveral Air Force Station needed tosend a signal to the flight termination system. Until the 45th Space Wing andobserver aircraft indicate that the skies are clear, Ares I-X will wait themout. 

6 thoughts on “Triboelectrification Questions? Try This.

  1. Dennis Hancock Post author

    Why is lycopodium powder such an effective agent for generating huge charges through triboelectricity?

  2. Brett Post author

    Has this always been a launch concern or is this a new criteria? I don’t believe in all the launches I’ve viewed of the Shuttle I’ve heard of this.

  3. lou josephs Post author

    Prove it. Was a ham operator working mobile from Playalinda Beach with voice and ssb. In thunderstorms, never an issue with anyone hearing me, running about 500 watts.
    Also worked at 1060WRMF and it’s FM at 98.3 plus did vhf links from press site 1 back to tville in t storms never an issue. Make this rule vanish..

  4. Graham Post author

    Well i think it’s a very sensible rule,especially for a data gathering test flight. You don’t want a massive static discharge ruining your down or uplink to the vehicle . They must have concerns otherwise it wouldn’t be in place .

  5. Steve Packard Post author

    Is this really necessary? The Sprint Missile (briefly in service with the Safeguard system) accelerated so quickly at low altitude that the entire vehicle became enveloped in a plasma. This would have made most control signals unreliable. Engineers had to fit it with a very high power microwave system to blast the signals through all the interference.

    Apollo 12 took off during high atmospheric electrical potential and was hit by a full fledged lightning bolt during the ascent. It triggered a systems shutdown that forced a reboot, but otherwise no major damage.

    Aircraft are routinely hit by lightning. The average passenger aircraft is hit as much as once a year and they constantly have to transmit data under conditions that are less than ideal.

    P-static rarely impairs communications with aircraft and it can be mitigated by using multiband high power transmitters when it does. The EA-6B and E-4B were both tested and confirmed to be able to transmit and receive reliably even under the most extreme conditions of having to fly through a thunderstorm during a massive geomagnetic storm caused by a potential nuclear attack.

  6. Thomas Wachtel Post author

    All things considered, it’s better to be safe than sorry in situations like this. The launch is expensive — somewhere in the neighborhood of $445 million — and in an economy like this, that’s a lot of money to spend on something that (though I am a strong supporter of renewed space exploration) isn’t exactly critical.

    There’s a lot to be accomplished by revitalizing the space program, and risks are going to be a necessary part of any such effort. But risking a waste of a large amount of money for a wholly unnecessary risk is foolish. If they’d launched in these conditions and been unable to receive transmissions, NASA would have looked foolish for wasting money for no gain. If they’d launched in these conditions and been unable to abort the flight, and (God forbid) there had been a catastrophe resulting in deaths, it would have been even worse.

    The delays cost money too, but they’re nowhere near as costly as taking foolish and unnecessary risks. If there’s a danger that can be avoided, avoid it.

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