Thanks, Dave, for all that info on potential dangers of composites, as well as the info about the lack of dangers in some cases. I agree, the unintended consequences of a new technology must be carefully considered before its implementation.
@3drob: You're right about carbon fibers causing a skin rash. It's not particularly serious from a medical perspective, but apparently it can cause a world of discomfort.
You're also absolutely right that it's important to consider all kinds of possibilities when evaluating a new technology.
Believe it or not, NASA actually did a study regarding the possibility of damage to electrical and electronic equipment resulting from the crashing of commercial airliners with carbon-fiber reinforced parts. Carbon fibers are electrically conductive, so presumably if they are released in the atmosphere after a crash, they could get into ground-based electronics and cause shorts. NASA did a fairly detailed analysis and concluded that this was very unlikely.
A lot of work has also been done on how carbon-fiber reinforced composites break up during atmospheric re-entry. This is actually something that's fairly well understood, since one use for carbon-fiber reinforced composites is as ablative barriers (where the break-up of the composite protects a capsule on re-entry).
Dave Palmer answered my question about inhalation dangers. I've heard from people that work with it that while fiberglass fibers work their way out of your skin, carbon fibers tend to work back into the skin (so the disintigration in atmosphere could be a source of polution).
My other question was centered on the idea that objects constructed of carbon fiber are fundamentally more durable than those constructed of standard materials. The assumption with a booster is that it will disintigrate on use (unlike prior applications like planes, well, at least hopefully planes). If so, they may not disintigrate as assumed and could become a hazard to earth bound objects (myself included). Even if they disintigrate, they may not become small enough pieces to be harmless. How durable are carbon fiber materials?
It wouldn't be the first time some game changing technology was introduced by Engineers who didn't re-examine long held prior assumptions.
@3drob: Inhalation of carbon fibers is not really all that dangerous, at least as far as inhalation of foreign substances goes. (When it comes to carbon nanotubes, it may be a different story). At any rate, the airborne concentration of carbon fibers produced by re-entry of a launch vehicle is likely to be extremely small -- the earth's atmosphere is really big, and fibers are likely to be widely dispersed by the time they reach ground level. Inhalation hazards are more of a concern for people working in composites manufacturing, where it is important to have adequate personal protective equipment.
Chuck, composites have been used in launchers before, but not for the entire shell. The reasons for their use are basically the same ones as in other aerospace apps: light weight and toughness. CFR composites just keep getting stronger. Here's some info from Hexcel:
A new service lets engineers and orthopedic surgeons design and 3D print highly accurate, patient-specific, orthopedic medical implants made of metal -- without owning a 3D printer. Using free, downloadable software, users can import ASCII and binary .STL files, design the implant, and send an encrypted design file to a third-party manufacturer.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.