Lunar Exploration and Science Orbiter (LExSO)

The Lunar Exploration and Science Orbiter (LExSO) mission concept is being developed to serve critical future lunar exploration and science measurement needs. LExSO is a lunar orbiter capable of accommodating a payload suite of highly capable instruments.

The mission concept is in pre-Phase A study with a science and engineering team based out of NASA Goddard Space Flight Center who developed and currently operate the Lunar Reconnaissance Orbiter (LRO). LExSO is envisioned to be a NASA Discovery class-like mission, reflecting the need for higher capability instruments and orbit adjustment flexibility.

There is a scientific need for continued orbital presence at the Moon. LRO is beyond its design lifetime and may not operational past the first few human Artemis landing missions (fuel is expected to run out as soon as 2027). LRO continues to be one of the most critical contributors to lunar science measuring anthropogenic as well as natural changes to the surface that can critically impact human exploration planning and safety needs.

This mission will significantly contribute to our understanding of the Moon by answering questions about surface geology, volatiles and support exploration needs. LExSO will address science and exploration drivers with increased measurement capabilities and significantly more orbital adjustment flexibility. LExSO will fill Artemis situational awareness, planning, and science gaps and with enhanced capability, enabling improvements to the LRO imagery and localized topography. 

LExSO goals are being carefully worked to provide a comprehensive suite including high resolution volatile/resource assessments, imaging and mapping, topography, temporal changes, navigation along with other science and Artemis exploration areas. A goal of the suite is to resolve both sunlit and permanently shadowed regions allowing investigation of anywhere on the lunar surface.

LExSO will uniquely fulfil global and targeted mapping capabilities that cannot be performed adequately from other orbits. The global imagery capability will allow detection of temporal changes and therefore assistance in knowing where to target the regional higher resolution measurements. A 50 km polar orbit, like LRO, constrains the possible measurement types but ensures global coverage. These constraints are driving the team to a cohesive set of goals that improve our understanding of the Moon but will inevitably leave some investigations in place for subsequent missions.