Editing Ranger program (section)

==Mission list==
===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]].

===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>

===Block 3 missions===
*[[Ranger 6]], launched 30 January 1964, lunar probe, Moon impact, cameras failed
*[[Ranger 7]]
**Launched 28 July 1964
**Impacted Moon 31 July 1964 at 13:25:49 UT
**{{coord|10.35|S|20.58|W|globe:Moon_type:landmark|display=inline|name=Ranger 7}} - [[Mare Cognitum]]
*[[Ranger 8]]
**Launched 17 February 1965
**Impacted Moon 20 February 1965 at 09:57:37 UT
**{{coord|2.67|N|24.65|E|globe:Moon_type:landmark|display=inline|name=Ranger 8}} - [[Mare Tranquillitatis]] (Sea of Tranquility)
*[[Ranger 9]]
**Launched 21 March 1965
**Impacted Moon 24 March 1965 at 14:08:20 UT
**{{coord|12.83|S|2.37|W|globe:moon_type:landmark|display=inline|name=Ranger 9}} - [[Alphonsus crater]]

Ranger's Block 3 embodied four launches in 1964-65. These spacecraft boasted a television instrument designed to observe the lunar surface during the approach; as the spacecraft neared the Moon, it would reveal detail smaller than the best Earth telescopes could show, and finally [[dishpan]]-sized craters.<ref>{{cite web|url=https://books.google.com/books?id=2sIfAAAAIAAJ&q=showing+dishpan-sized+craters&pg=PA47|title=The View From Ranger|year=1961|publisher=NASA-JPL|page=47}}</ref> The first of the new series, [[Ranger 6]], had a flawless flight, except that the television system was disabled by an in-flight accident and could take no pictures.

The next three Rangers, with a redesigned television, were completely successful. [[Ranger 7]] photographed its way down to target in a lunar plain, soon named [[Mare Cognitum]], south of the crater [[Copernicus (lunar crater)|Copernicus]]. It sent more than 4,300 pictures from six cameras to waiting scientists and engineers. The new images revealed that craters caused by impact were the dominant features of the Moon's surface, even in the seemingly smooth and empty plains. Great craters were marked by small ones, and the small with tiny impact pockmarks, as far down in size as could be discerned—about {{convert|50|cm|in|abbr=off|sp=us}}. The light-colored streaks radiating from Copernicus and a few other large craters turned out to be chains and nets of small craters and debris blasted out in the primary impacts.

In February 1965, [[Ranger 8]] swept an oblique course over the south of [[Oceanus Procellarum]] and [[Mare Nubium]], to crash in [[Mare Tranquillitatis]] about {{convert|70|km|mi|sp=us}} distant from where [[Apollo 11]] would land 4½ years later. It took more than 7,000 images, covering a wider area and reinforcing the conclusions from Ranger 7. About a month later, [[Ranger 9]] came down in the {{convert|90|km|mi|adj=on|abbr=off|sp=us}} diameter crater [[Alphonsus (crater)|Alphonsus]]. Its 5,800 images, nested concentrically and taking advantage of very low-level sunlight, provided strong confirmation of the crater-on-crater, gently rolling contours of the lunar surface.

[[Image:Ranger 6789.svg|thumb|250px|center|Ranger block III spacecraft diagram. (NASA)]]