On the 25 of January the Russian Post issued a stamp to commemorate the 100th anniversary of the birth of Mstislav Keldysh.
The stamp features a portrait of the scientist, the first artificial Earth satellite and Keldysh's formula (on the completeness of the eigenfunction).
Mstislav Keldysh was a Soviet scientist in the field of mathematics and mechanics. He was one of the key figures behind Soviet space program. Among scientific circles of USSR Keldysh was known with epithet "the Chief Theoretician".
The crater Keldysh on the Moon, and a research vessel Akademik Mstislav Keldysh are named after him. A minor planet, 2186 Keldysh discovered in 1973 by Soviet astronomer Lyudmila Chernykh, is also named in his honor.