Radar studies involving
Arecibo (
Puerto Rico),
Goldstone (
California, United States), and the
Very Large Array (
New Mexico, United States) detected a number of highly-radar-reflective depolarized areas on Mercury, including several locations at the planet's
poles. Many of these reflective features appear to coincide with craters imaged by
Mariner 10, with the largest feature at the south pole corresponding to Chao Meng-Fu crater. The luminosity and depolarization of the radar reflections are much more characteristic of ice than of the
silicate rocks making up Mercury's
crust. Still, these reflections are too dim to be pure ice; it has been hypothesized that this is due to a thin or partial layer of powder over the underlying ice. However, with no direct confirmation, it is always possible that the observed radar reflectivity from Chao Meng-Fu and similar craters is due to depositions of
metal-rich minerals and compounds.
NASA's
MESSENGER mission confirmed the strong correlation of radar reflectivity with permanently shadowed craters, as shown on the maps to the right.
Ice origins Chao Meng-Fu's ice may have originated from impacts of water-rich
meteorites and
comets or from internal
outgassing. Due to bombardment by the
solar wind and intense light from the Sun, ice deposits on most of Mercury would be rapidly lost to space; in the permanently shadowed portions of Chao Meng-Fu, though, temperatures are too low to permit appreciable
sublimation and ice may well have accumulated over billions of years. ==Chao Meng-Fu crater in fiction==