Ranger 1 was intended to test new technologies that would take humankind to the Moon and other planets. Credit: NASA/JPL-Caltech

Nation United States of America
Objective(s) Highly Elliptical Earth Orbit
Spacecraft P-32
Spacecraft Mass 675 pounds (306.18 kilograms)
Mission Design and Management NASA/Jet Propulsion Laboratory
Launch Vehicle Atlas Agena B (Atlas Agena B no. 1 / Atlas D no. 111 / Agena B no. 6001)
Launch Date and Time Aug. 23,1961 / 10:04 UT
Launch Site Cape Canaveral Air Force Station, Fla. / Launch Complex 12
Scientific Instruments 1. Electrostatic Analyzer
2. Photoconductive Particle Detectors
3. Rubidium Vapor Magnetometer
4. Triple-Coincidence Cosmic-Ray Telescope
5. Cosmic-Ray Integrating Ionization Chamber
6. X-Ray Scintillation Detectors
7. Micrometeoroid Dust Particle Detectors
8. Lyman Alpha Scanning Telescope

Key Dates

Aug. 23, 1961 | 10:04 UT: Launch


Ranger 1 was the first in a series of standardized spacecraft designed to take photos of the lunar surface in advance of soft landing missions. The spacecraft consisted of a tubular central body connected to a hexagonal base containing basic equipment required for control and communications. Power was provided by solar cells and a silver-zinc battery.

Ranger 1’s specific mission was to test performance of the new technologies intended for later Ranger missions and to study the nature of particles and fields in interplanetary space. Its intended orbit was 37,300 x 684,000 miles (60,000 × 1.1. million kilometers).

Ranger 1 was the first American spacecraft to use a parking orbit around Earth prior to its deep space mission.

In this case, the Agena B upper stage cut off almost immediately after its ignition for translunar injection (instead of firing for 90 seconds). The probe remained stranded in low Earth orbit (311 x 104 miles or 501 × 168 kilometers) and telemetry ceased by Aug. 27, 1961 when the main battery went dead. The spacecraft reentered Earth’s atmosphere three days later.

The cause of the Agena failure was traced to a malfunctioning switch which had prematurely choked the flow of red fuming nitric acid to the rocket engine.


Siddiqi, Asif A. Beyond Earth: A Chronicle of Deep Space Exploration, 1958-2016. NASA History Program Office, 2018.

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