The next generation gamma‐ray spectrometer after the planned Nuclear Astrophysics Explorer (NAE) could be based on the Moon to use the lunar regolith for shielding the detectors from cosmic rays and neutrons. This increased shielding over what could reasonably be put in low‐Earth orbit would provide a narrow line sensitivity (3&sgr;) of ∼2×10−7photons cm−2s−1at 1 MeV in 106s, which is about 10 times better than the NAE and 100 times better than GRO/OSSE.