Trailblazer of the Week
Christopher S. Edwards
26 June 2020
Christopher S. Edwards’s favorite thing to do is to jump off a boat into some warm, clear water and float around.
“I really like sailing,” says Edwards, one of Lunar Trailblazer’s co-investigators. As Assistant Professor of Physics and Astronomy at Northern Arizona University (NAU), he steers a research group designing remote sensing instruments, specializing in infrared spectroscopy.
Edwards had been studying business as an undergraduate at Arizona State University when he took an elective introductory course in planetary science. His instructor happened to be Dr. Laurie Leshin, who later became a deputy associate administrator for NASA. Then, after what he deems another “stroke of luck,” Edwards wound up working for Dr. Phil Christensen, then a co-investigator on Mars Exploration Rover missions. These mentorships helped secure his interest in planetary geology; outer space became the new bottom line.
“I switched my major and wound up getting a Ph.D. in geological sciences,” says Edwards. “I just never realized that you could have a career studying planets and rocks, and going camping! I always liked rocks even as a kid, so this path was pretty intriguing.”
Apart from spearheading his research group at NAU, Edwards is currently involved with several ongoing missions in addition to Trailblazer, like the Mars Science Laboratory Curiosity Rover, the Mars Odyssey Thermal Emission Imaging System (THEMIS), the Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx), and the upcoming Emirates Mars Infrared Spectrometer (EMIRS) on Hope.
“As far as a typical day goes, it usually starts with emails and an early morning telecon related to mission work,” Edwards says. “I feel very lucky to be able to think up crazy ideas to explore other planets, work on missions that include roving around Mars with Curiosity, and orbiting the Moon and Mars. My background is in Mars remote sensing and instrument development, so a lot of what I do is link what instruments can measure to the things we want to measure of other planetary bodies.”
Cue the Moon. Edwards is working on the Lunar Trailblazer mission to design and develop the temperature mapping metrics.
“I’m excited to see the physical properties of the surface at smaller scales than we’ve ever seen before from orbit,” he says.
Trailblazer’s Lunar Thermal Mapper (LTM) is optimized to measure the temperatures of the surface within the select range of wavelengths being analyzed for water by the High-resolution Volatiles and Moon Mineralogy Mapper (HVM3), Lunar Trailblazer’s spectrometer. Edwards is tasked with ensuring the precise co-observation of Trailblazer’s two instruments.
“My role on Trailblazer is partially to link the two wavelength ranges covered by HVM3 and LTM together to help better correct the thermal emission of the surface around the 3 micron region.”
The key wavelength for water and hydroxyl is around 3 micrometers in the infrared, and although past missions have remotely detected this spectral signature, they left some questions open related to its composition, abundance, or distribution in part because the Moon was previously assumed to be totally anhydrous. The discovery of water has now prompted the Trailblazer team and Edwards to equip LTM and HVM3 to fully investigate the 3-micron region, providing a more complete inventory of water and volatiles on the Moon at higher resolutions than ever before. Edwards is most excited by this co-alignment of LTM and HVM3.
“This will really help address a lot of the challenges we have now when looking for hydroxyl and water with existing datasets, as we’ll have both data at the same scale, taken at the same time. We really need the two datasets acquired together to fully assess the influence of the surface temperature on the 3-micron spectral feature,” he says. “It’s going to be great!”
Lunar Trailblazer’s recurring measurements at different times of the lunar day will also chart any dynamic behavior of the Moon’s water, and not just yield correlations to particular mineralogical composition or tie it to any one location. By measuring the surface at three distinct times of the lunar day — essentially lunar morning, noon, and evening — Lunar Trailblazer will determine if fluctuating temperatures throughout a lunar day actually drive an active lunar water cycle at the surface.
“It’s not only an important dataset for future human exploration of the Moon, but it also has implications for how the Moon evolved with time and is the way it is today,” says Edwards. “I like working in between science and engineering, developing new instruments to make the measurements that we need to answer fundamental questions about our solar system. A lot of times you want to build the ‘super instrument,’ to make all the measurements you could ever want, but we’re always working within constraints on power, size, mass and viewing geometry, to name a few. Some of the most challenging aspects are deciding what's the most important scientifically that can be achieved within the constraints of the mission.”
Personal collaboration on Trailblazer has easily been far less of a challenge for Edwards.
“Because it’s such a small mission and science team, it's easy to get really involved,” he says. “Many missions, like Curiosity, have hundreds of scientists on them and it’s hard to carve out a role for yourself. On Trailblazer I know everyone, which is great!”
Christopher S. Edwards is a co-investigator for Trailblazer's Lunar Thermal Mapper and Trailblazer of the Week!
Trailblazer of the Week is an ongoing series showcasing the diversity of experience and expertise that supports the collective determination of the Lunar Trailblazer mission.
By Emily Felder
Emily Felder is a Pasadena City College student and Caltech intern working on science communication for the Lunar Trailblazer mission.