Prior to the conduct of ASTP, the astronauts and cosmonauts visited each other's space centers and became familiar with the spacecraft of the other country. The first visit was by the Russians to Johnson Space Center in July 1973, followed by a U.S. visit to Moscow in November 1973. In late April and early May 1974, the Russian flight crews returned to Johnson Space Center, and the U.S. crews went to Moscow in June and July 1974. The Russian crew made a third trip to the United States in September 1973 and came for the fourth and last time in February 1975. The U.S. crew visited the Soviet Union in late April and early May 1975 and became the first Americans to see the Russian launch facilities at Tyuratam on April 28, 1975. During the visit of American Astronauts they participated in the Ceremony of Tree Planting in the Star City (Cosmonaut Training Center)