Visualizing the Next Frontier: How Optical Filters are Shaping Lunar Exploration
Returning to the moon has long been a goal for space exploration and research. To achieve this, researchers are developing new instruments, with optics and photonics technologies playing a crucial role. Technologies like multispectral filters and spectrometers are essential for these tools, providing high-resolution imaging, precise spectroscopy and accurate navigation in harsh space environments.
John Hopkins Applied Physics Laboratory, a leader in space infrastructure technologies and research, is working on such instruments by developing the Mahina Color Camera, or MahinaCam.
Created under NASA’s Development and Advancement of Lunar Instrumentation (DALI) program, the MahinaCam provides data on the composition of rocks and soils on the lunar surface through specialized pattern filters, enhancing the understanding of lunar geology and processes that have shaped it. Because commercial and scientific presence on the moon depends on access to useful minerals, the development of MahinaCam is a key technology that will enable sustainable lunar permanence and research opportunities.
MahinaCam is built on commercial-off-the-shelf (COTS) camera components with a CMOS focal plane made for many applications. As a low-cost and low-resource instrument, it could be used on landers and rovers collecting data on titanium and iron content and the degree of space weathering of materials at a landing site, distant locations or along rover traverse.
Torrent’s custom spectral filters help make this possible. They created the optimal camera solution because they have high transmission, strong out-of-band blocking and the ability to align the multispectral filters to an image sensor. Bonded directly to the detector, the pattern filters are used to collect multispectral images in the visible to near infrared.
Torrent’s filter design was optimized to enable Johns Hopkins to maximize resolution by keeping the Bayer pattern as small as possible. Additionally, Torrent has a unique ability to align the custom Bayer filter pattern to the sensor array. Learn more about Torrent's custom filter capabilities.
Conventional red-green-blue imaging systems are limited in their ability to determine lunar composition because their spectral bands are broad and overlap. The three wavelength filters in the MahinaCam are set at a baseline of 430, 750, and 940 nm, mapping lunar composition and optical properties by capturing key spectral characteristics of lunar materials. It also encompasses the key ferrous-iron (Fe2+) absorption band near 950 nm, which is a diagnostic of lunar silicate minerals.
The hope for future MahinaCam uses and advancements include wavelength filters suited for conducting science at other locations such as sites of volcanism and polar regions. Filters like the ones used in Mahinacam can be customized for other industries such as life science, agriculture and ordinance detection.