Wow! I have many years experience in the aerospace industry. I have seen composites used, long ago, for upper stages, which operate in space. I have not seen that done for the while launcher. It should not be suprising considering what is being done for aircraft. This is really interesting and a real breakthrough.
I'd be interested to learn if the range-safety package had to be scaled up or down for the material change. The range-safety package is (usually) an explosive designed to rip open the booster in a controlled manner in case of loss of control. This permits the propellant to burn at altitude and at zero pressure (instead of in the thrust chamber).
Is it easier or more difficult to split the side of a composite booster?
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:
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: 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).
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: 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.
A postcard or post card is a rectangular piece of thick paper or thin cardboard intended for writing and mailing without an envelope. There are novelty exceptions, such as wood postcards, made of thin wood, and copper postcards sold in the Copper Country of the U.S. state of Michigan, and coconut "postcards" from tropical islands.
In some places, it is possible to send them for a lower fee than for a letter. Stamp collectors distinguish between postcards (which require a stamp) and postal cards (which have the postage pre-printed on them). While a postcard is usually printed by a private company, individual or organization, a postal card is issued by the relevant postal authority.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.