ESSA-9
Encyclopedia
ESSA-9, also known as TOS-G, was a meteorological satellite. ESSA-9 replaced the ESSA-7 satellite.
from Cape Canaveral
, Florida
. The launch occurred at 07:47 UTC (02:47 EDT
) on 26 February 1969. The spacecraft was placed in a sun-synchronous orbit
of 101.4° inclination. The ESSA-9 had a perigee of 1427 kilometres (886.7 mi) and an apses of 1508 kilometres (937 mi). It circled the earth once every 115.2 minutes, or 12.5 times a day.
satellites in it was an 18 sided polygon that measured 42 inches (106.7 cm) in diameter and was 22 inches (55.9 cm) high. It weighed 320 pounds (145.1 kg). The body of the ESSA-9 was made of aluminum alloy and stainless steel
. The shell of the craft was covered with 10,020 solar cells. The solar cells recharged the 63 nickle-cadmium batteries
during the time in which the spacecraft was in sunlight. The ESSA-9 employed the same cartwheel-style stabilization as the TIROS
-9 satellite. The satellite used a Magnetic Attitude Spin Coil (MASC) to control its attitude while in orbit. The magnetic field induced by the current interacted with the earth's magnetic field to provide the torque necessary to maintain a desired spin rate of 9.225 rpm.
.
Launch & orbit
The ESSA-9 was launched on a three stage Delta rocketDelta rocket
Delta is a versatile family of expendable launch systems that has provided space launch capability in the United States since 1960. There have been more than 300 Delta rockets launched, with a 95 percent success rate. Two Delta launch systems – Delta II and Delta IV – are in active use...
from Cape Canaveral
Cape Canaveral
Cape Canaveral, from the Spanish Cabo Cañaveral, is a headland in Brevard County, Florida, United States, near the center of the state's Atlantic coast. Known as Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated from it by the Banana River.It is part of a region known as the...
, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. The launch occurred at 07:47 UTC (02:47 EDT
Eastern Time Zone
The Eastern Time Zone of the United States and Canada is a time zone that falls mostly along the east coast of North America. Its UTC time offset is −5 hrs during standard time and −4 hrs during daylight saving time...
) on 26 February 1969. The spacecraft was placed in a sun-synchronous orbit
Sun-synchronous orbit
A Sun-synchronous orbit is a geocentric orbit which combines altitude and inclination in such a way that an object on that orbit ascends or descends over any given point of the Earth's surface at the same local mean solar time. The surface illumination angle will be nearly the same every time...
of 101.4° inclination. The ESSA-9 had a perigee of 1427 kilometres (886.7 mi) and an apses of 1508 kilometres (937 mi). It circled the earth once every 115.2 minutes, or 12.5 times a day.
Spacecraft
The ESSA-9 spacecraft was similar to that of the TIROSTIROS
TIROS, or Television Infrared Observation Satellite, is a series of early weather satellites launched by NASA, beginning with TIROS-1 in 1960. TIROS was the first satellite that was capable of remote sensing of the Earth. This initial remote-sensing effort was significant because it enabled Earth...
satellites in it was an 18 sided polygon that measured 42 inches (106.7 cm) in diameter and was 22 inches (55.9 cm) high. It weighed 320 pounds (145.1 kg). The body of the ESSA-9 was made of aluminum alloy and stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
. The shell of the craft was covered with 10,020 solar cells. The solar cells recharged the 63 nickle-cadmium batteries
Nickel-cadmium battery
The nickel–cadmium battery ' is a type of rechargeable battery using nickel oxide hydroxide and metallic cadmium as electrodes....
during the time in which the spacecraft was in sunlight. The ESSA-9 employed the same cartwheel-style stabilization as the TIROS
TIROS
TIROS, or Television Infrared Observation Satellite, is a series of early weather satellites launched by NASA, beginning with TIROS-1 in 1960. TIROS was the first satellite that was capable of remote sensing of the Earth. This initial remote-sensing effort was significant because it enabled Earth...
-9 satellite. The satellite used a Magnetic Attitude Spin Coil (MASC) to control its attitude while in orbit. The magnetic field induced by the current interacted with the earth's magnetic field to provide the torque necessary to maintain a desired spin rate of 9.225 rpm.
Instruments
The ESSA-9 carried 2 sets of 2 instruments, the Advanced Vidicon Camera System (AVCS) and the Flat Plate Radiometer (FPR). The AVCS was used to collect imagery of cloud cover on earth. The cameras had a resolution of 2 miles (3.2 km) and covered an area of 2000 square miles (5,180 km²). The cameras would take an image of each place once a day. The FPR's were used to measure the global distribution of solar radiation reflected by the earth and the earth's atmosphere. They also measured long wave emissions from the earth. The sensors were contributed to the ESSA satellites by the Nimbus programNimbus program
The Nimbus satellites were second-generation U.S. robotic spacecraft used for meteorological research and development. The spacecraft were designed to serve as stabilized, Earth-oriented platforms for the testing of advanced systems to sense and collect atmospheric science data...
.