We developed a monolithic...
HOLMS, or Heterodyne OH Lunar Miniaturized Spectrometer, is a fairly new type of spectrometer that has several advantages over traditional spectrometers. HOLMS uses an interferometric technique, Spatial Heterodyne Spectrometry (SHS), which has ten times higher spectral resolution and five times higher etendue (E=AW) and sensitivity compared to state-of-the-art spectrometers, with comparable performance. It also is ten times smaller in mass and volume than these other spectrometers. Additionally, it has no moving parts, which is particularly advantageous in space travel, where temperature changes and the stresses of launch and landing could normally cause parts to become misaligned. HOLMS is currently configured to obtain spectral signatures of water components for OH at 3082 Å over a narrow bandpass range (3067-3138 Å), and because of HOLMS’ high spectral resolution (DlR= 0.085 Å), both OH and OD can be directly and simultaneously detected to provide an unambiguous method to measure the D/H ratio. HOLMS’s small size means that many of the instruments can be made and deployed at one time, and if one is lost, the mission can still succeed because there are others. Its small size also means that it can be added to missions with other primary objectives, which also brings the cost down, since a mission does not have to be developed specifically for this instrument. It is versatile and suited to be used on multiple platforms and to travel to many locations in space.