Characterization of the Intuitive Machines (IM-1) Lunar Landing Site Near the South Pole

A major milestone for the commercial lunar sector was attained by Intuitive Machines’ lander Odysseus (IM-1), which successfully soft-landed near the lunar south pole on February 22, 2024. The Odysseus mission was the second launch of the NASA’s lunar CLPS (Commercial Lunar Payload Services) program and the first to successfully reach the Moon. Despite coming to rest at an unplanned angle of ~30°, the spacecraft was able to communicate with Earth and remained operational for a week on the lunar surface.

 

Here we use available orbital data to characterize the geologic context of the IM-1 landing site, with an emphasis on Mini-RF bistatic radar data, LROC image data, and LOLA and LROC topographic data. One of the science goals of the Lunar Reconnaissance Orbiter (LRO)’s extended mission is to support future lunar landings by analyzing orbital data over future, current, and past landed missions in order to better constrain and “ground truth” the orbital data. Landing site characterization is a key element in planetary surface exploration as a mission that does not land safely is over before it begins.

 

Odysseus touched down in an intercrater region about 10° latitude from the lunar south pole (~300 km) at 80.13°S, 1.44°E. The landing site lies on a ~12° slope east of the irregular, degraded Malapert A crater (33 km in diameter) and roughly equidistant between craters Malapert B, Malapert C, and Malapert K (32, 38, and 39 km in diameter, respectively). Notably, the site is very close to the ring of discontinuous massifs that constitute the outer rim of South Pole-Aitken Basin.

 

The landing site was as expected in that it is a typical highlands site that consists of mostly low, rolling terrain, formed by an accumulation of ancient ejecta and interrupted by craters; steep slopes are largely limited to crater interior walls. Odysseus landed adjacent to the rim of an ancient crater measuring about 1.2 km in diameter. No high concentrations of rough-textured ejecta or hazardous boulders that are commonly found surrounding fresh craters were observed in the Mini-RF radar data, a finding consistent with the view from the lander. Unlike on the mare, small craters in the highlands (<5 to 10 km in diameter) tend not to excavate many boulders. Therefore, the lack of a radar signature consistent with abundant rocks is in agreement with Diviner-derived rock abundance measurements for non-polar terra regions that are generally low (rocks occupy <0.5% of the surface). If Odysseus had been a sample-centric mission, those samples would likely have been regolith-dominated (unlike Apollo 16 in the highlands where there were abundant boulders).