After Korolyov
Korolyov died in January 1966 following a routine operation that uncovered colon cancer and from complications from heart disease and severe hemorrhaging. Kerim Kerimov, who was formerly an architect of Vostok 1, was appointed Chairman of the State Commission on Piloted Flights and headed it for the next 25 years (1966–1991). He supervised every stage of development and operation of both manned space complexes as well as unmanned interplanetary stations for the former Soviet Union. One of Kerimov's greatest achievements was the launch of Mir in 1986.
Leadership of the OKB-1 design bureau was given to Vasili Mishin, who had the task of sending a man around the Moon in 1967 and landing a man on it in 1968. Mishin lacked Korolyov's political authority and still faced competition from other chief designers. Under pressure Mishin approved the launch of the Soyuz 1 flight in 1967, even though the craft had never been successfully tested on an unmanned flight. The mission launched with known design problems and ended with the vehicle crashing to the ground, killing Vladimir Komarov. This was the first in-flight fatality.
Following this disaster and under new pressures, Mishin developed a drinking problem. The Soviets were narrowly beaten in sending the first manned flight around the Moon in 1968 by Apollo 8, but Mishin pressed ahead with development of the problematic super heavy N1 rocket in the hope that the Americans would have a setback, leaving enough time to make the N-1 workable and land a man on the moon first. There was a success with the joint flight of Soyuz 4 and Soyuz 5 in January 1969 that tested the rendezvous, docking and crew transfer techniques that would be used for the landing, and the LK Lander was tested successfully in earth orbit. But after four unmanned test launches of the N-1 ended in failure, the heavy booster was abandoned and with it any chance of the Soviets landing men on the moon in a single launch.
Besides the manned landings, abandoned Soviet moon program included a building the multipurpose moonbase Zvezda, first detailed such project with developed mockups of expedition vehicles and surface modules. Later proposed new moon manned program "Vulkan-LEK" were not adopted on economic reasons.
Following this setback, Chelomei convinced Ustinov to approve a program in 1970 to advance his Almaz military space station as a means of beating the US's announced Skylab. Mishin remained in control of the project that became Salyut but the decision backed by Mishin to fly a three-man crew without pressure suits rather than a two-man crew with suits to Salyut 1 in 1971 proved fatal when the re-entry capsule depressurized killing the crew on their return to Earth. Mishin was removed from many projects, with Chelomei regaining control of Salyut. After working with NASA on the Apollo Soyuz Test Project, the Soviet leadership decided a new management approach was needed and in 1974 the N-1 was cancelled and Mishin dismissed. A single design bureau was created NPO Energia with Glushko as chief designer.
Despite of failure of manned lunar programs, USSR achieved a significant success with two historical firsts, the automatic Lunokhod and the Luna sample return missions. Also, the Mars probe program was continued with some small success, while the explorations of Venus and then of the Halley comet by Venera and Vega probe programs was more effective.
Read more about this topic: Soviet Space Program