Friday, June 24, 2005

Two bad ants (ok, one good ant and one bad ant...)

Yesterday I listened to two presentations: one was the ultimate pile-up of presentation pitfalls, and the other was a model of top-form talk technique. (Sorry…alliteration helps me wake up in the morning…)

Eric Pencil (infamous for using a portable microphone and speaker system when we took a tour of his lab) was discussing research in electric propulsion, which is a very interesting topic. Electric propulsion means we could carry more stuff faster and further into space. There are various types of electric propulsion thrusters that are being developed (and Eric Pencil tried to mention every single one of them…), but they all involve “the acceleration of gasses for propulsion by electrical heating and/or electric and magnetic body forces.” (See, I was taking notes!) Some of the problems for electric propulsion include:
-life-span limitations of the thrusters (they get corroded by metal sputtering caused by the pummeling of components by ions). They are by design meant to be used for prolonged periods of time (because they rely on a continuous acceleration that is relatively small).
-size and weight of thrusters (the bigger they are, the more powerful they are).
-Integrating the thrusters into missions, because they require a large amount of power to run (i.e., could require a nuclear reactor). For example, they are going to test some electric propulsion thrusters on the ISS, but it doesn’t really have any extra power to give. How are they going to manage that?

But…Eric Pencil just glossed over these issues. Instead of discussing them, he listed every single electric propulsion project in development, what companies and universities are collaborating on it, the project’s timeline, and what it should be able to do when it is complete. He must have gone through about 20 different types of thrusters (and for each one he tried to cram all of the aforementioned information onto a single slide that was unreadable).

When he finally opened it up to questions, someone asked if there are any applications for electric propulsion methods on Earth. (Why, Eric Pencil, didn’t you already address this in your talk?) He said that they are very useful for creating thin carbon films and coatings, and can also be used to inject plasma into combustion processes to increase the amount of thrust produced.

In the afternoon Matt Melis gave a presentation on the Space Shuttle Columbia Accident Investigation and the “Return to Flight” initiative (for those of you that haven’t been following closely, the Space Shuttle Discovery’s STS-114 launch window opens on July 13th), specifically on his involvement with impact testing. I was supposed to introduce Matt Melis, but at the last minute Dr. Kankam stole my thunder (because, he said, it was a presentation that wasn’t just for students…psh). Anyway, Matt Melis works in the Ballistics Impact Lab, where they use pressurized cannons to shoot things at other things. For the past two and a half years, they have been devoting a lot of their time to shooting insulating foam (the stuff that is used to keep the 1.6 million pounds of liquid oxygen hydrogen in the space shuttle’s external cold while it’s sitting in the humid pre-launch Florida climate) at reinforced carbon carbon (which serves as thermal insulation for the wings of the space shuttle, which have to withstand a 3000 degree C inferno upon re-entry). Reinforced carbon carbon, while being a great insulator, is very brittle, and so when a piece of foam from the external fuel tank hit the wing of the Columbia at around 500 mph during takeoff, it shattered the reinforced carbon carbon insulation, which ultimately led to the wing burning up during the shuttle’s return trip through the Earth’s atmosphere.

Matt Melis’ talk was awesome because he gave all sorts of relevant background information (on how the shuttle works, on the accident investigation—which included months of scouring the landscape near the crash for every single possible piece of debris they could find, on the accident itself, and on the processes that go into preparing the shuttle for a mission), was very passionate about this topic (he said as soon as he finds out exactly when the launch will be he’s going to jump in his car and drive town to Kennedy), and he presented his findings in a very engaging way (lots of rad pictures and movies of collisions). Matt Melis showed us high speed footage of all sorts of pieces of foam hitting things, and ice hitting things, and even a full-scale test of a space shuttle wing that he did.

The talk was excellent. The only painful part was when this guy (who had been sleeping during the entire talk) tried to attack Melis for being biased and only presenting one hypothesis for why the shuttle crashed (even though Melis had emphasized that without video evidence there is never any way to know for sure what happened, and he also discussed just how many people poured over the evidence and brainstormed and whatnot for months—no wait, years—before coming to their conclusion). That guy was a total asshole.

Ok, that’s about it for the science-y stuff.

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