Those watching the launch countdown (and hold, and scrub) may have heard the term 'triboelectrification' used as a reason to postpone and finally scrub the launch. So what is triboelectrification? If you ever received static shock on a winter day after walking across the carpet, or watched how abalone clings after rubbing it on your head, you have experienced triboelectrification - the production of electrostatic charges by friction.
Specifically, NASA is concerned about a type of triboelectrification they refer to as "P-static" (the P is for precipitation). If the rocket ascends through a cloud, the water in the cloud can produce a corona of static that may interfere with telemetry coming from and to the rocket. In a worst case scenario, a malfunctioning and wayward rocket may not receive the destruct signal from the range safety officer at Cape Canaveral due to this corona.
NASA uses ground based weather observations, weather balloons, and observer aircraft provided by the 45th Space Wing at Patrick Air Force Station. Once they give the all clear, we can get under way!
By the way, the launch of Apollo 12 taught NASA the danger of turboelectric shock when the Saturn V was launched during a mild rain. As the Saturn booster sped through the rain clouds, it became the world's longest lightning rod. A bolt of electricity had struck the spacecraft and traveled all the way to the ground, 6,000 feet below, along the column of hot, charged gases of the Saturn's exhaust plume. The bolt knocked the Apollo spacecraft's power-producing fuel cells off line, and astronauts saw more warning lights then they had ever encountered in a simulation training. Even though Ares I-X is uncrewed, NASA is still understandably reluctant to again tempt such a fate.
Saturn V Launch Umbilical Tower struck by lightning from Apollo 12
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