Figure A

The High-resolution Volatiles and Minerals Moon Mapper (HVM³), seen here, is one of two instruments that will be carried aboard NASA's Lunar Trailblazer. Launching in 2023, the small spacecraft – measuring only 11.5 feet (3.5 meters) wide with its solar panels fully deployed – will detect and map water on the Moon's surface to determine its abundance, location, form, and how it changes over time.

HVM³ recently completed a significant milestone in a clean room at NASA's Jet Propulsion Laboratory in Southern California. The high-resolution spectrometer measures the infrared light (with wavelengths from 0.6 to 3.6 microns in size) that is absorbed by water. To make sure the instrument is properly aligned, the Trailblazer team cooled HVM3 down to temperatures it will experience in space and made tiny physical adjustments to make sure all the wavelengths of incoming light arrive at the correct locations on the instrument's detector.

Figure A shows several members of the Trailblazer team surrounding the instrument – minus its radiator and electronics – mounted on HVM³'s optical bench assembly while undergoing cold alignment.

The assembly was placed inside a thermal vacuum chamber and brought to a cold focal plane operating temperature of about minus 240 degrees Fahrenheit (minus 155 degrees Celsius). The team then measured light of different wavelengths across all of the detector's pixels. Based on the data recorded, the team calculated the small adjustments that needed to be made, took the instrument out of the chamber and made those changes, placed it back into the chamber, and then repeated the steps iteratively until HVM³ was in perfect alignment.

With this important step complete, a radiator will next be installed to ensure the instrument maintains optimal operating temperatures while Trailblazer is in orbit around the Moon. Then, vibration tests will be carried out to make sure the spectrometer will stay in alignment after the extreme shaking of launch.

Lunar Trailblazer was selected to be part of NASA's SIMPLEx (Small Innovative Missions for Planetary Exploration) program in 2019. The mission is led by Caltech in Pasadena, California, and managed by JPL.

For more information about Lunar Trailblazer's mission: https://trailblazer.caltech.edu/