Animation: The Science Behind HVM³’s Search for Lunar Water Explained

26 July 2024

Water isn’t flowing on the Moon, but it may exist as water ice at the lunar poles or be bound within rock as hydroxide at the sunlit surface. Lunar Trailblazer seeks to determine these forms of water and pinpoint where they are distributed with two science instruments.

First is the Lunar Thermal Mapper (LTM), which will measure temperature emitted from the surface to determine rock composition. Second is the High Resolution Volatiles and Minerals Moon Mapper (HVM³) which will measure light reflecting off the surface to locate water and determine its composition. Together, these instruments will create the first-ever maps of lunar water.

But how, exactly, will HVM³ identify water composition? In Lunar Trailblazer’s newest animation, intern and Pasadena City College student Emily Felder explains how the spectrometer’s advanced design will locate and differentiate lunar water.

“Communicating how a hyperspectral imaging spectrometer is optimized for the infrared detection of volatiles to map the various forms of lunar water was challenging to visually render,” says Felder. “It was critical to first understand the nature and properties of light, spectroscopy, and lunar geology to explain the instrument’s form and function.”

Animation frame depicting how light moves through Lunar Trailblazer's HVM³ instrument. Credit: Emily Felder (PCC/Caltech)

Felder’s greatest challenge was visualizing how HVM³ ultimately creates an “image cube,” the sequence of stacked images representing the spectrum of reflected light in many wavelengths at a targeted location on the Moon.

“Illustrating how an instrument can produce a three-dimensional cube from light reflecting off of a two-dimensional surface involved many sketches to make sure I was accurately portraying this high-fidelity science to a general audience,” says Felder. “I hope this animation serves as a guide for anyone interested in Trailblazer’s mission science and lunar spectral data.”

Animation frame depicting an image cube and the information contained within a single pixel. Credit: Emily Felder (PCC/Caltech)