on the
Moon. (right) from
Apollo 15. ISOCHRON would address fundamental questions about the composition of the lunar crust and the time-stratigraphy of lunar volcanic processes, with implications for all of the terrestrial planets. There is a stretch of nearly 2 billion years of lunar history that planetary scientists have not been able to date because the
Apollo missions did not retrieve any young rocks. Lunar mare basalts formed through partial melting of the
mantle, thus serve as probes of the
structure and composition of the interior. The stated scientific objective of the mission is: "[To] make high-precision
radiometric age measurements on these relatively young basalts to fill the existing gap in age-correlated crater size-frequency distributions (CSFDs), thereby greatly improving this widely-used tool for estimating the ages of exposed surfaces on rocky bodies." The proposed ISOCHRON mission concept would have a robotic lander land just south of
Aristarchus plateau and retrieve about of a
basalt sample estimated to be 1.5 to 2.0 billion years old. The sample would be placed in a small container, launched to Earth, and it would be curated at NASA's
Lunar Sample Laboratory Facility. The
Principal Investigator is Dave Draper, at NASA's Johnson Space Center in Texas. ==Location==