The instrument is a low-frequency radio spectrometer to provide radio spectra from 10 kHz - 10 MHz (or possibly 30 MHz) with 1-second resolution. These Radio wave Observations at the Lunar Surface of the photoElectron Sheath (ROLSES) will permit determination of the photoelectron sheath density from ~0-2 m above the lunar surface, using antennas at 1 m and 2 m above the surface (see figure). This is of scientific value and is also important to determine if there will be an effect on the antenna response of larger lunar radio observatories with antennas on the lunar farside.
Read more about the Intuitive Machines - IM-1 Mission and an recent article from Ars Technica, Ars takes a close-up look at the first US lunar lander in half a century.