Mission Type: Orbiter
Launch Vehicle: Atlas-Able (no. 1 / Atlas D no. 20)
Launch Site: Cape Canaveral
Spacecraft Mass: 169 kg
Spacecraft Instruments:
1) high-energy radiation counter
2) ionization chamber
3) Geiger-Mueller tube
4) low-energy radiation counter
5) two magnetometers
6) photo-scanning device
7) micrometeoroid detector
8) aspect indicator
9) radio receiver to detect natural radio waves
10) transponder to measure electron densities
References:
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, by Asif A. Siddiqi, NASA Monographs in Aerospace History No. 24

This mission used the first of four spacecraft designed by Space Technology Laboratories for a lunar assault in 1959 and 1960; two of them had originally been slated for Venus orbit (in June 1959), but mission planners had redirected their missions after the success of the Soviet Luna 3 mission.

All the scientific experiments and internal instrumentation were powered by nickel-cadmium batteries charged from 1,100 solar cells on 4 paddles. Each probe also carried an internal hydrazine monopropellant motor for lunar orbit insertion at a range of 8,000 km from the Moon. Ideal lunar orbital parameters were planned as 6,400 x 4,800 km The missions also inaugurated the first use of the Atlas-with-an-upper-stage combination, affording increased payload weight.

During this first launch, the nose fairing began to break away just 45 seconds after liftoff. Aerodynamic forces then caused the third stage and payload to break away and explode. The ground lost contact with the tumbling booster at T+104 seconds. Investigation showed that the 3-m fiberglass shroud failed because there had been no measures to compensate for pressure differentials as the rocket gained altitude.

Editor's Note: This mission profile is from an originally published mission profile in Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, by Asif A. Siddiqi, NASA Monographs in Aerospace History No. 24.