Objectives: The satellite was designed to sense meteorological conditions from a fixed location above the Earth, and to provide this data to operational forecasters and private interests on the ground. It was the first geostationary satellite to provide continuous vertical profiles of atmospheric temperature and moisture.

Description: The spacecraft was a cylinder 85 inches in diameter, 138 inches high and weighed 874 pounds. The sides of the cylinder were covered by 15,000 solar cells which, along with nicad batteries, provided the power for the craft. Contained within, but protruding from the base was the primary instrument - the VAS (Visible Infrared Spin Scan Radiometer (VISSR) Atmospheric Sounder) and its sunshade. This instrument provided both day and night imagery of cloud conditions as well as temperature and moisture profiles over the full-disk. Unfortunately, the dwell times of sounder versus imager do not permit these two operations to occur simultaneously; however, soundings are still available on an hourly basis.

The satellite also used new despun S-band and UHF antennas to improve the relay of meteorological data from over 10,000 surface locations into a central processing center for incorporation into numerical weather prediction models, and to perform facsimile transmission of processed images and weather maps to WEFAX field stations. In addition, a Space Environment Monitor (SEM) and Data Collection System (DCS) similar to those on the previous GOES were installed.

GOES-4 was placed in a geostationary orbit directly over the equator over the Pacific (135W).

Participants: NASA, NOAA, Hughes Aircraft, McDonnell Douglas