Geological Chronicle
Fermi is a walled plain on the Moon’s far side, where it must be viewed from an orbiting spacecraft. It cannot be seen from Earth. The prominent crater Tsiolkovskiy intrudes into Fermi’s southeastern rim. Unlike Tsiolkovskiy, Fermi’s interior is not covered by dark basaltic lava, leaving it barely distinguishable from the surrounding rugged and battered terrain.
If Fermi were on the Moon’s near side, it would be one of the largest visible craters, with a dimension roughly equal to Humboldt. The crater Humboldt lies several hundred kilometers to the west-southwest. This formation dates to the Pre-Nectarian period. An infrared spectrum of pure crystalline plagioclase has been identified on the northwest floor.
Subsequent impacts have significantly eroded and damaged the rim. Delporte crosses the northwest rim; Just east and inside the northern rim lies Litke; Xenophon is centered across the southern rim. Diderot and Babakin lie in the southern half of the floor. Where it survives, the rim is most intact in the north; the southern half is nearly obliterated, forming an irregular stretch of ground.
Tsiolkovskiy’s formation modified Fermi’s floor, with striations in the northeast and parallel ridges along the western rim of Tsiolkovskiy. Some remaining floor sections are somewhat more level, though marked by myriads of tiny craterlets and several clustered crater formations near the center. Previously identified as Basin V, the crater was named for Italian-American physicist Enrico Fermi, a Nobel laureate in 1938. The IAU formally adopted its designation in 1970.