Weather Satellites: NIMBUS I

NIMBUS I

Launch date: August 28, 1964

Launch site: Vandenberg Air Force Base, California

Launch vehicle: Thor-Agena B

PROGRAM OBJECTIVE:

To test the NIMBUS spacecraft configuration and provide improved cloud photographs using the APT system deployed on TIROS VIII. Advanced cameras and high resolution infrared radiometers were also to be tested for improved daylight as well as night cloud cover conditions.

SATELLITE DESCRIPTION:

The spacecraft was designed in two sections. The lower circular ring housed the meteorological sensors and electronics. The upper hexagonal section contained the attitude control system and had two solar panels (containing 10,500 individual panels) attached to its sides. The two sections were constructed by a magnesium truss. The lower ring was 57 inches in diameter. The total spacecraft height was 118 inches while the width across the solar panels was 134 inches. The total weight of the spacecraft was 830 pounds.

The craft contained three cameras with direct readout and delayed readout capabilities. A high resolution infrared radiometer operated in the 3.4 to 4.2 micron region. Two horizon scanners, sun sensors and freon gas jets provided the attitude control.

Premature Agena cutoff left the craft in an elliptical orbit rather than a more circular one and one of the solar panels failed 26 days into the mission. In spite of these problems, 27,000 pictures were taken and 60 ground stations were involved in the direct readout of this imagery. The infrared imagery was much clearer than those sampled by the TIROS series. NIMBUS I remained operational until September 23, 1964.

PARTICIPANTS:

NASA, General Electric, ITT, Fairchild - Hiller, RCA, US Weather Bureau.