Ranger Program

The Ranger series was the first U.S. attempt to obtain close-up images of the Lunar surface. The spacecraft were designed to fly straight down towards the Moon and send images back until the moment of impact, to rough-land a seismometer capsule on the Moon, to collect gamma-ray data in flight, and to study radar reflectivity of the Lunar surface. All this was being done in order to "scout" locations for a planned manned landing on the Moon.

The basic spacecraft was 3.1 m high and consisted of a lunar capsule 65 cm in diameter, a mono-propellant mid-course motor, a 5,080-pound thrust retrorocket, and a gold- and chrome-plated hexagonal base 1.5 m in diameter. A large high-gain dish antenna was attached to the base. Two wing-like solar panels, each 5.2 m across, were attached to the base and deployed early in the flight. Power was generated by 8,680 solar cells.

Each Ranger spacecraft had 6 cameras on board, each of which provided better resolution than was available from Earth-based views by a factor of 1000. Other apparatus carried by the spacecraft were a gamma-ray spectrometer, a radar altimeter, and a seismometer to be rough-landed on the Lunar surface.

The image at left was taken by Ranger 7 about 17 minutes before impact; the one at right was taken immediately before impact.

Ranger Mission	Launch Date	Impact Date	Mission Notes
Ranger 1	August 23, 1961		Failed to leave Earth parking orbit
Ranger 2	November 18, 1961		Failed to leave Earth parking orbit
Ranger 3	January 26, 1962		Earth contact lost; missed the Moon by ~36,800 km
Ranger 4	April 23, 1962		Sequencer failed; impacted the Moon on April 26
Ranger 5	October 18, 1962		Earth contact lost; missed the Moon by 725 km
Ranger 6	January 30, 1964		Cameras failed; impacted the Moon on February 2, 1964
Ranger 7	July 28, 1964	July 31, 1964	Mare Cognitum (Sea That Has Become Known)
Ranger 8	February 17, 1965	February 20, 1965	Mare Tranquillitatis (Sea of Tranquility)
Ranger 9	March 21, 1965	March 24, 1965	Alphonsus crater