The Colorado High-resolution Echelle Stellar Spectrograph (CHESS) is designed to study the interstellar medium (ISM) in the ultraviolet part of the spectrum, the matter between stars, and specifically translucent clouds of gas which provide fundamental building blocks for star and planet formation. These clouds have very low densities and the only way to study them is to measure absorption spectra of light from stars passing through the cloud. CHESS will be pointed at the star Gamma Ara, in the southern constellation Ara. With this fourth flight of the Colorado High-resolution Echelle Stellar Spectrograph (CHESS-4) sounding rocket payload, sightlines at the lower-edge of the translucent cloud regime can be sampled. This mission aims to study translucent clouds by analyzing the ultraviolet absorption spectra of the two most abundant molecules (H2 and CO) that reside within them.

The Principal Investigator was Dr. Kevin France/University of Colorado Boulder.