Weather Satellites: TIROS IX

TIROS IX - Television Infrared Observation Satellite IX

Launch date: January 22, 1965

Launch site: Cape Canaveral, Florida

Launch vehicle: Three-stage Delta

PROGRAM OBJECTIVE:

To test the "cartwheel" configuration and a polar orbit of the TIROS in preparation for the Weather Bureau's completely operational TOS (TIROS Operational Satellites) system.

SPACECRAFT DESCRIPTION:

The spacecraft was an 18-sided polygon, 42 inches in diameter, 19 inches high and weighed 270 pounds. This was the heaviest TIROS satellite thus far. The craft was made of aluminum alloy and stainless steel then covered with 9200 solar cells. The solar cells served to charge the 63 nickel-cadmium batteries.

TIROS IX'S camera configuration was different than any previous TIROS craft. The two cameras were mounted 180 degrees opposite each other along the side of the cylindrical craft rather than in the base plate parallel to the rotation axis. Therefore, a camera could be pointed at some point on Earth every time the satellite rotated along its axis. The spacecraft operating system was the same as in the previous TIROS models except that two infrared horizon sensors were employed. The craft was placed in its planned sun-synchronous 82 degree retrograde orbit, but a Delta malfunction placed the satellite in a 435 to 1602 mile elliptical orbit instead of a 400 mile circular orbit. The satellite spin axis was rotated using the magnetic attitude control system into an alignment perpendicular to the orbital plane and tangent to the EarthÕs surface. Thus the "cartwheel" configuration was achieved. This configuration was eventually adopted for the ESSA operational series of civilian weather satellites.

The first photomosaic of the entire world's cloud cover was achieved via a composite of 450 photos taken on February 13, 1965. Although additional maneuvers were necessary to keep the craft from overheating, TIROS IX remained operational for 1238 days until deactivated by NASA on June 12, 1968.

PARTICIPANTS:

NASA, RCA, US Weather Bureau.