Posted on Oct 28, 2009 11:24:29 AM | Dan Kanigan | 6 Comments
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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 (What the Heck is That?)
The skies look clear except for some high clouds, there’s no rain in the immediate forecast, so why might a rocket not launch? The answer is something called 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 a cat 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 around the rocket that interferes with radio signals sent by or to the rocket. This would create problems when the rocket tries to transmit data down to the ground or if the Range Safety Officer at Cape Canaveral Air Force Station needed to send a signal to the flight termination system. Until the 45th Space Wing and observer aircraft indicate that the skies are clear, Ares I-X will wait them out.
Tags : General
6 comments so far ( Post your own )
- 6
On Oct 31, 2009 06:59:11 PM
Steve Packard
wrote:
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.- 5 On Nov 01, 2009 05:49:57 PM Thomas Wachtel wrote:
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.- 4 On Oct 29, 2009 05:42:56 AM Graham wrote:
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 .
- 3 On Oct 28, 2009 04:19:33 PM lou josephs wrote:
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..- 2 On Oct 28, 2009 01:16:47 PM Brett wrote:
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.
- 1 On Oct 28, 2009 12:20:13 AM Dennis Hancock wrote:
Why is lycopodium powder such an effective agent for generating huge charges through triboelectricity?
- 5 On Nov 01, 2009 05:49:57 PM Thomas Wachtel wrote:
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