Editing Mare Imbrium (section)

=== Apollo 15 ===
In 1971, the crewed [[Apollo 15]] mission landed in the southeastern region of Mare Imbrium, between [[Hadley–Apennine|Hadley Rille]] and the [[Montes Apenninus|Apennine Mountains]]. Commander [[David Scott]] and Lunar Module Pilot [[James Irwin]] spent three days on the surface of the Moon, including 18½ hours outside the spacecraft on lunar [[extra-vehicular activity]]. Command Module Pilot [[Alfred Worden]] remained in orbit and acquired hundreds of high-resolution photographs of Mare Imbrium (and other regions of the Moon) as well as other types of scientific data.  The crew on the surface explored the area using the first [[Lunar Roving Vehicle|lunar rover]] and [[Sample return mission|returned to Earth]] with {{convert|77|kg}} of lunar surface material.  Samples were collected from [[Mons Hadley Delta]], believed to be a fault block of pre-Imbrian ([[Nectarian]] or [[Pre-Nectarian]]) lunar crust, including the "[[Genesis Rock]]."  This was also the only Apollo mission to visit a lunar rille, and to observe outcrops of lunar bedrock visible in the rille wall.<ref>[https://www.hq.nasa.gov/alsj/a15/as15psr.pdf Apollo 15 Preliminary Science Report] (NASA SP-289), Scientific and Technical Information Office, National Aeronautics and Space Administration, Washington, D.C., 1972.</ref>