The State Scientific Centre Keldysh Research Center is a research institute based at 8 Onezhskaya street () in Moscow, Russia. It is a Federal State Unitary Enterprise that is part of the Russian Space Agency. Previously known as the Reaction-Engine Scientific Research Institute (, Reaktivnyy nauchno-issledovatel’skiy institut, РНИИ, RNII), it is now named after M. V. Keldysh, one of the key figures behind the Soviet space program.