Editing Ranger program (section)

===Block 2 missions===
[[File:20180328 Ranger restoration Udvar-Hazy.jpg|thumb|A Ranger probe undergoing restoration at the [[Udvar-Hazy Center]]]]

*[[Ranger 3]], launched 26 January 1962, lunar probe, spacecraft failed, missed Moon
*[[Ranger 4]], launched 23 April 1962, lunar probe, spacecraft failed, Moon impact
*[[Ranger 5]], launched 18 October 1962, lunar probe, spacecraft failed, missed Moon

Block 2 of the Ranger project launched three spacecraft to the Moon in 1962, carrying a TV camera, a radiation detector, and a seismometer in a separate capsule slowed by a rocket motor and packaged to survive its low-speed impact on the Moon's surface. The craft weighed 331&nbsp;kg. The three missions together demonstrated good performance of the Atlas/Agena B launch vehicle and the adequacy of the spacecraft design, but unfortunately not both on the same attempt. [[Ranger 3]] had problems with both the launch vehicle and the spacecraft, missed the Moon by about 36,800&nbsp;km, and has orbited the Sun ever since. [[Ranger 4]] had a perfect launch, but the spacecraft was completely disabled. The project team tracked the seismometer capsule to impact just out of sight on the [[Far side (Moon)|lunar far side]], validating the communications and navigation system. [[Ranger 5]] missed the Moon and was disabled. No significant science information was gleaned from these missions.

Around the end of Block 2, it was discovered that a type of diode used in previous missions produced problematic gold-plate flaking in the conditions of space. This may have been responsible for some of the failures.<ref>{{cite web|url=https://history.nasa.gov/SP-480/ch8.htm|title=ch8}}</ref>