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Links to broadcast quality audio files and transcripts. David Des Marais, an astrobiologist at NASA Ames Research Center, Moffett Field, Calif. is interviewed about the 2003 Mars Exploration Rover mission (MER). Des Marais is a member of the science operation working group of the 2003 MER mission. He is also the principal investigator for the Ames Team of the NASA Astrobiology Institute. This interview was recorded 6-2-03

Question 13. What is a spectrometer?

The audio recording is 1:40 minutes.

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Full Transcript (below)

13. What is a spectrometer?(1:40 minutes)

David Des Marais: "The main camera – sort of like the visual wavelength camera – has several filters on each of the two eyes of the camera, and they can be turned around so that you can look at the scene through different colored, ah, filters, and with that sort of reconstruct how intense the wavelengths of light are at different wavelengths. Ahh, this can be used to tell you a little bit about the composition of the material that you’re looking at. And particularly in the visible range, we can say a lot about the kind of iron that’s out there. I think everyone’s familiar how rust looks like on an iron pipe. And there are different kinds of rust, even. Some are very much darker brown colors. Others are more of the bright red that we normally think of as rust. This – these different colors give us information about the exact kinds of iron minerals that are present. So, iron is a very good element to look at in terms of just the visible light that we can see. The infrared – now we’re talking about the kind of radiation that you feel when you stand next to a fireplace or next to a heater – That heat that you’re feeling on your face is infrared radiation, and it, too, is made up of several different wavelengths of radiation. And by analyzing the relative abundances of these different wavelengths, we can say something about the kinds of minerals that are out there emitting a sort of a heat that we can pick up with our instrument. And so, for example, we could tell whether we are looking at carbonates or minerals made out of silica, or other kinds of minerals made out of sulfates. And so even just now by looking at the light – err, the infrared light coming off of these rocks from a distance, we can begin to get an idea of their composition based on how those minerals produce these certain wavelengths of infrared radiation."

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