TIROS-4 (also called TIROS-D and A9) was a spin-stabilized

meteorological satellite A weather satellite or meteorological satellite is a type of Earth observation satellite that is primarily used to monitor the weather and climate of the Earth. Satellites are mainly of two types: polar orbiting (covering the entire Earth asyn ...

. It was the fourth in a series of

Television Infrared Observation Satellite Television InfraRed Observation Satellite (TIROS) is a series of early weather satellites launched by the United States, beginning with TIROS-1 in 1960. TIROS was the first satellite that was capable of remote sensing of the Earth, enabling sc ...

Launch

TIROS-4 was launched on February 8, 1962, by a

Thor-Delta The Thor-Delta, also known as Delta DM-19 or just Delta was an early American expendable launch system used for 12 orbital launches in the early 1960s. A derivative of the Thor-Able, it was a member of the Thor family of rockets, and the first ...

rocket from

Cape Canaveral Air Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the sta ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

. The spacecraft functioned nominally until June 30, 1962. The satellite orbited the

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

once every 1 hour and 30 minutes, at an inclination of 48.3°. Its

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

was and

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

was .

Mission

The satellite was in the form of an 18-sided right prism, 107 cm in diameter and 56 cm high. The top and sides of the

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

were covered with approximately 9000 1- by 2-cm

silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...

solar cell A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.

s. It was equipped with two independent television camera subsystems for taking cloud cover pictures and three radiometers (two-channel low-resolution, omnidirectional, and five-channel scanning) for measuring radiation from the Earth and its

atmosphere An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

. The satellite spin rate was maintained between 8 and 12

rpm Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 def ...

by the use of five diametrically opposed pairs of small solid-fuel thrusters. The TIROS-4 spin axis could be oriented to within 1° to 2° accuracy by use of a magnetic control device consisting of 250 cores of wire wound around the outer surface of the spacecraft. The interaction between the induced

magnetic field A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...

in the spacecraft and the

Earth's magnetic field Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from structure of Earth, Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from ...

provided the necessary torque for attitude control. The flight control system also optimized the performance of the

solar cell A solar cell, also known as a photovoltaic cell (PV cell), is an electronic device that converts the energy of light directly into electricity by means of the photovoltaic effect.

s and television cameras and protected the 5 channel infrared radiometer from prolonged exposure to direct sunlight. With the exception of the degraded response of the 5 channel scanning

radiometer A radiometer or roentgenometer is a device for measuring the radiant flux (power) of electromagnetic radiation. Generally, a radiometer is an infrared radiation detector or an ultraviolet detector. Microwave radiometers operate in the micro ...

, the spacecraft performed normally until May 3, 1962, when one camera failed. On June 10, 1962, the other camera's tape recorder failed. The scanning radiometer provided usable data until June 30, 1962.''Journal of the British Interplanetary Society'', Vol. 19, pags. 386-409, 1963-1964

Gallery

File:Thor Delta with Tiros 4 (Feb. 8 1962)-repair.jpg, TIROS-4 launch on February 8, 1962 by a

rocket File:TIROS Composite Spac0082-repair.jpg, TIROS-4 images of northwestern United States on April 11, 1962 File:Tiros 4 mosaic.jpg, TIROS-4 pictures of Gulf of St. Lawrence and surroundings

References

External links

TIROS
Encyclopedia Astronautica
Real Time Satellite Tracking - TIROS 4
N2yo.com. {{DEFAULTSORT:Tiros-4 Weather satellites of the United States Spacecraft launched in 1962 Television Infrared Observation Satellites