ESSA

The Environmental Science Services Administration (ESSA) Satellite Program was initiated as an extension of, and a compliment to, the TIROS Program. Like TIROS, the ESSA Program's primary objective was to provide cloud-cover photography to the American National Meteorological Center.

Over a period of almost 4 years, ESSA satellites transmitted thousands of images back to Earth, enabling ground stations to predict weather patterns, including hurricanes. Advances in technology allowed ESSA to more than double the amount of information gathered over the life of the program. When ESSA-6, was deactivated by NASA, its images were reaching more than 300 receiving stations around the world, in 45 countries.

ESSA imagery was of a much wider scope, and better resolution, than the TIROS 9 program. ESSA design and missions were the result of a combined effort on the part of NASA, the Environmental Science Services Administration, the US Weather Bureau and the National Meteorological Center. Its success prompted further exploration of using space-borne weather prediction and monitoring devices, like ATS and the NIMBUS series.

The ESSA-1 satellite provided cloud-cover photography to the US's National Meteorological Center for the purpose of preparing operational weather analyses and forecasts. The spacecraft was designed and configured exactly the same as NIMBUS-1. The total weight of the spacecraft was 912 pounds.

The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 305 pounds. The craft was made of aluminum alloy and stainless steel then covered with 9100 solar cells. The solar cells served to charge the 63 nickel-cadmium batteries.
The two cameras were mounted 180-degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS 9 was selected as the orbital configuration of the operational series of ESSA satellites. 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 on the TIROS 9. The craft was placed in its planned Sun-synchronous 98-degree inclination retrograde 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 Earth's surface. ESSA-1 was able to view the weather of each area of the globe, photographing a given area at the exact same local time each day.

ESSA-1 Stats:

Objectives for the ESSA-2 was to complement ESSA-1 and provide direct-readout cloud-cover photography to ground stations worldwide using APT.

The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 290 pounds. The craft was made of aluminum alloy and stainless steel then covered with 9100 solar cells. The solar cells served to charge the 63 nickel-cadmium batteries.
The two cameras were mounted 180-degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS-9 was selected as the orbital configuration for the ESSA satellites. 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 on the TIROS-9. The craft was placed in its planned Sun-synchronous 101 degree inclination retrograde orbit. The APT system was designed to transmit an image every 352 seconds, each photo covering a 2000-square mile area with 2-mile resolution.

ESSA-2 was able to transmit two to three images daily to individual ground stations, regardless of their location.

ESSA-2 Stats:

ESSA-3 satellite replaced ESSA-1. It provided cloud-cover photography to the US's National Meteorological Center for the purpose of preparing weather analyses and forecasts. The spacecraft was designed and configured exactly the same as NIMBUS-1. The total weight of the spacecraft was 912 pounds.

The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 320 pounds; it was made of aluminum alloy and stainless steel, then covered with 9100 solar cells. The solar cells served to charge the 63 nickel-cadmium batteries.
The two cameras were mounted 180-degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS-9 was selected as the orbital configuration for the ESSA satellites. 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 on the TIROS-9. The craft was placed in its planned Sun-synchronous 101 degree inclination retrograde orbit. The ESSA-3 system transmitted images covering 2000-square mile areas with 2-mile resolution from every location once per day.

ESSA-3 Stats:

The ESSA-4 satellite replaced ESSA-2 and provided direct readout cloud-cover photography to ground stations worldwide using APT. The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 290 pounds; it was made of aluminum alloy and stainless steel, then covered with 9100 solar cells. The solar cells served to charge the 63 nickel-cadmium batteries.

The two cameras were mounted 180-degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS-9 was selected as the orbital configuration of the ESSA satellites. 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 on the TIROS-9. The craft was placed in its planned Sun-synchronous 101-degree inclination retrograde orbit. The APT system was designed to transmit an image every 352 seconds, each photo covering a 2000-square mile area with 2-mile resolution. ESSA-4 was able to transmit two to three images daily to individual ground stations regardless of their location.

ESSA-4 Stats:

The ESSA-5 satellite replaced ESSA-3 and provided cloud-cover photography to the US's National Meteorological Center for the purpose of preparing weather analyses and forecasts. The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 320 pounds; it was made of aluminum alloy and stainless steel then covered with 9100 solar cells, used to charge the 63 nickel-cadmium batteries.

The two cameras were mounted 180 degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS-9 was selected as the orbital configuration for the ESSA satellites. 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 on the TIROS-9. The craft was placed in its planned Sun-synchronous 102-degree inclination retrograde orbit. The ESSA-5 system transmitted images covering 2000-square mile areas with 2-mile resolution from every location once per day. The ESSA-5 satellite replaced ESSA-3 and provided cloud-cover photography to the US's National Meteorological Center for the purpose of preparing weather analyses and forecasts.

The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 320 pounds; it was made of aluminum alloy and stainless steel then covered with 9100 solar cells, used to charge the 63 nickel-cadmium batteries.
The two cameras were mounted 180 degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS-9 was selected as the orbital configuration for the ESSA satellites. 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 on the TIROS-9. The craft was placed in its planned Sun-synchronous 102-degree inclination retrograde orbit. The ESSA-5 system transmitted images covering 2000-square mile areas with 2-mile resolution from every location once per day.

ESSA-5 Stats:

The ESSA-6 replaced ESSA-4 and provided direct readout cloud-cover photography to ground stations worldwide using APT. The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 290 pounds; it was made of aluminum alloy and stainless steel then covered with 9100 solar cells, which served to charge the 63 nickel-cadmium batteries.

The two cameras were mounted 180 degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS-9 was selected as the orbital configuration of the ESSA satellites. 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 on the TIROS-9. The craft was placed in its planned Sun-synchronous 101-degree inclination retrograde orbit. The APT system was designed to transmit an image every 352 seconds, each photo covering a 2000-square mile area with 2-mile resolution.

ESSA-6 was able to transmit up to eight images daily to individual ground stations around the world. A total of 305 receiving stations were now operational around the world, including 26 US universities, 25 US television stations, and the weather services of 45 foreign countries.

ESSA-6 Stats:

The ESSA-7 satellite replaced ESSA-5 and provided cloud cover photography to the US's National Meteorological Center for the purpose of preparing operational weather analyses and forecasts. The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 320 pounds. The craft was made of aluminum alloy and stainless steel then covered with 9100 solar cells. The solar cells served to charge the 63 nickel-cadmium batteries.

The two cameras were mounted 180-degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS-9 was selected as the orbital configuration of the operational series of ESSA satellites. 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 on the TIROS-9. The craft was placed in its planned Sun-synchronous 102-degree inclination retrograde 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 Earth's surface. The ESSA-7 system transmitted images covering 2000-square mile areas with 2-mile resolution from every location once per day. Two arrays of radiometer sensors were also mounted 180-degrees apart to measure the global distribution of solar radiation reflected by the Earth and the Earth's atmosphere, as well as the long wave emissions from the Earth (a contribution from the NIMBUS program).

ESSA-7 Stats:

The ESSA-8 satellite replaced ESSA-6 and provide direct readout cloud-cover photography to ground stations worldwide using APT. The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 290 pounds. The craft was made of aluminum alloy and stainless steel then covered with 10,020 solar cells. The solar cells served to charge the 63 nickel-cadmium batteries.

The two cameras were mounted 180-degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS 9 was selected as the orbital configuration of the operational series of ESSA satellites. 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 on the TIROS-9. The craft was placed in its planned Sun-synchronous 101-degree inclination retrograde 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 Earth's surface. The APT system was designed to transmit an image every 352 seconds, each photo covering a 2000-square mile area with 2-mile resolution. ESSA-8 was able to transmit eight to ten images daily to nearly 400 individual ground stations around the world.

ESSA-8 Stats

The ESSA-9 satellite replaced ESSA-7 and provided cloud-cover photography to the US's National Meteorological Center for the purpose of preparing operational weather analyses and forecasts. The spacecraft was an 18-sided polygon, 42 inches in diameter, 22 inches high and weighed 320 pounds. The craft was made of aluminum alloy and stainless steel then covered with 10,020 solar cells. The solar cells served to charge the 63 nickel-cadmium batteries.

The two cameras were mounted 180-degrees opposite each other along the side of the cylindrical craft. The "cartwheel" configuration of the TIROS-9 was selected as the orbital configuration of the operational series of ESSA satellites. 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 on the TIROS-9. The craft was placed in its planned Sun-synchronous 102-degree inclination retrograde 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 Earth's surface. The ESSA-7 system transmitted images covering 2000-square mile areas with 2-mile resolution from every location once per day. Two arrays of radiometer sensors were also mounted 180-degrees apart to measure the global distribution of solar radiation reflected by the Earth and the Earth's atmosphere, as well as the long wave emissions from the Earth (a contribution from the NIMBUS program).

ESSA-9 stats:

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