|Launch Date||August 17, 1958 | 12:18 UT|
|Launch Site||Eastern Test Range | Launch Complex 17A|
|Alternate Names||Able 1, Thor-Able 1|
Break out of Earth orbit and reach lunar orbit. Study and photograph the moon's surface, detect micrometeoroid impacts and report back on spacecraft performance in deep space.
None. The launch vehicle exploded 77 seconds after launch.
This mission was the first of two U.S. Air Force (USAF) launches to the moon and the first attempted deep space launch by any country.
The Able 1 spacecraft, a squat, conical, fiberglass structure, carried a crude infrared TV scanner. This device was a simple thermal radiation device comprising a small parabolic mirror for focusing reflected light from the lunar surface onto a cell that would transmit voltage proportional to the light it received.
Engineers painted a pattern of dark and light stripes on the spacecrafts outer surface to regulate internal temperature. The spacecraft was also disinfected with ultraviolet light prior to launch.
According to the ideal mission profile, Able 1 was designed to reach the moon 2.6 days after launch; then the TX-8-6 solid propellant motor would fire to insert the vehicle into orbit around the moon. Altitude would have been 29,000 kilometers with an optimal lifetime of about two weeks.
The actual mission, however, lasted only 77 seconds after the Thor first stage exploded at 15.2 kilometers altitude. The upper stages hit the Atlantic about 123 seconds later. Investigators concluded that the accident had been caused by a turbopump gearbox failure. The mission has been retroactively known as 'Pioneer 0.'
Launch Vehicle: Thor-Able 1 (Thor no. 127)
Spacecraft Mass: 84 pounds (38 kg)
- micrometeoroid detector
- temperature sensors
- infrared camera
Siddiqi, Asif A. Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, NASA, 2002.