Ranger 1 was launched on August 23, 1961. Its objective was to develop and test basic elements of spacecraft technology required for lunar and interplanetary missions. The spacecraft made 111 orbits of Earth and traveled 3,000,000 miles. Ranger 3 was launched on January 26, 1962. This was the first attempt by the United States to take closeup pictures of the Moon and to make measurements on the lunar surface, However, Ranger 3 arrived at intercept with the Moon's orbit too early because of excess launch vehicle velocity. No photos were taken. The spacecraft flew by the Moon at a distance of 22,862 miles. Ranger 7 was launched on July 28, 1964 and impaced the Moon at the Sea of Clouds on July 31, 1964. Its objective was to acquire and transmit photographs of the lunar surface before impacting the Moon. Ranger 7 became the first U.S. spacecraft to obtain close-up photographs of the Moon and subsequently transmitted 4,316 images of the surface. Rangers 8 and 9 also reached the Moon and took many photographs before impacting. The other Ranger spacecraft failed for a variety of reasons. Prior to the United States' effort to land a probe on the surface of the Moon, the Soviet Union launched its Luna series. Though the first of these, Luna 1, did not reach the Moon, it did become the first probe to escape from the Earth and enter heliocentric orbit. Luna 2, launched on September 12, 1959, impaced the Moon near the Sea of Serenity. Luna 3, launched October 4, 1959, became the first spacecraft to image the far side of the Moon. Luna 9, launched January 31, 1966, achieved the first semi-soft landing on the surface of the Moon. After landing, the probe transmitted TV images of its surroundings. The Luna program continued until 1976. The series included the launches of 24 missions to the Moon, several of which were successful in analyzing soil samples, returning soil samples to the Earth, and studying the gravitational field.
