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Way Cool Scientist!

Wendy Calvin Do you ever wonder why, when you hold a crystal up to the window on a summer day, the colors of the rainbow begin to dance around the room? Different materials will absorb different colors, both those that are visible to the naked eye, and those that are not. We can identify both minerals and ices by their signature measured at many wavelengths, called a 'spectrum'. Think about the crystal again--as the light passes through the prism, the colors that you see are the 'spectrum' of sunlight. Each material has its own signature, kind of like a fingerprint. The study of this signature is called 'spectroscopy,' which is the backbone of Dr. Wendy Calvin's research.

Dr. Calvin and her colleagues work on satellite and aircraft pictures that are taken at a number of visible and infrared wavelengths to study surface rocks and minerals on Earth and other planets. As a member of the science team for the 2003 Mars Exploration Rover (MER) Mission, Calvin will analyze data as it comes back from the infrared spectrometer called Mini-TES. Interpreting the spectra of Mars will involve comparisons to minerals we find here on Earth and measurements we’ve made, both in the laboratory and in the field. This builds on Calvin’s previous research, nearly 15 years spent studying Martian spectra, as well as terrestrial rock and mineral signatures.

Dr. Calvin uses a field instrument to measure the infrared spectrum of rocks near Virginia City, NV.

The Mini-Thermal Emission Spectrometer, or Mini-TES, is an instrument that sees infrared radiation emitted by objects. Scanning mirrors reflect light to the instrument located at the bottom of the rover's mast. The Mini-TES will determine from afar the mineral composition of Martian surface features and select specific rocks and soils to investigate in detail. In addition to determining mineral composition of Martian surface materials, Mini-TES will be pointed upward to make the first ever high-resolution temperature profiles through the Martian atmosphere's boundary layer.

Calvin's interest in ices includes her hobbies of backcountry and downhill skiing. Here she listens in on the avalanche potential of an alpine snowpack.
Calvin is particularly interested in ices. On Earth we have water ice and dry ice (CO2), but far out in the solar system things like nitrogen and methane also freeze. And, since there is so much oxygen here on Earth and so little on Mars, Calvin is curious about how minerals on the surface of Mars should weather. She's hoping the MER rovers will uncover more clues about these inquiries.

In preparation for the MER Mission, Calvin studies the surface materials of our planet. She works with three graduate students who research materials that may be similar to those found on Mars. They work on a computer analyzing pictures taken from airplanes or from satellites in orbit, and they often go out to the areas where the pictures were taken to confirm that what they see in the aerial photography is, in fact, what they find on the ground. The team takes field instruments along with them on these expeditions. Calvin considers this to be one of the most enjoyable parts of her job--hiking around, looking at rocks, and using field equipment.

Calvin had a spark for science at a young age. As a kid, she loved solving story problems and basic algebra, and she loved playing around with science equipment. She remembers demonstrating interference phenomena "in a pool of water and standing waves on a wire with a little battery and a magnet." She thought this was all "pretty cool." She also loved reading Harriet the Spy and especially liked Harriet's buddy, Janie, who blew up the house with the chemistry set in her room. Interestingly enough, one of her favorite high school experiments was charting the orbit of Mars. "We had to observe its position every week for several months," says Calvin. Fortunately she lived where the night skies were very dark and Mars was easy to find!

Calvin in her office studies a geologic map of Mars.

While maintaining the curiosity and excitement that she felt as a child, Calvin also holds a deep respect for the challenges inherent in planetary exploration. She recalls the Samurai saying, "Expect nothing; be prepared for anything." By its nature, exploration is fraught with detours, unexpected outcomes, and things that work only part-way. "Just think of Columbus," Calvin says, "who went to find a new route to Asia and got the West Indies instead--or Scott, who wanted to be first to the South Pole but lost his life and his crew in the process." She remembers being in grad school when the Shuttle Challenger blew up--a sobering reminder of the potential danger involved in the active quest for knowledge. Along the way there have been both spectacular successes and disheartening losses. “We must learn from the failures, but we must always have the courage to continue,” says Calvin.