Editing Ranger program (section)

===Block 1 missions===
[[Image:Ranger Block 1 scientific experiments.jpg|thumb|250px|right|Ranger block I spacecraft diagram. (NASA)]]

*[[Ranger 1]], launched 23 August 1961, lunar prototype, launch failure
*[[Ranger 2]], launched 18 November 1961, lunar prototype, launch failure

Block 1, consisting of two spacecraft launched into Earth orbit in 1961, was intended to test the [[Atlas-Agena]] launch vehicle and spacecraft equipment without attempting to reach the Moon.

Problems with the early version of the launch vehicle left [[Ranger 1]] and [[Ranger 2]] in short-lived, low-Earth orbits in which the spacecraft could not stabilize themselves, collect solar power, or survive for long. In 1962, JPL utilized the Ranger 1 and Ranger 2 design for the failed [[Mariner 1]] and successful [[Mariner 2]] deep-space probes to [[Venus]].