USA-47, also known as GPS II-4 and GPS SVN-19, was an American
navigation satellite
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. It allows satellite navigation devices to determine their location (longitude, latitude, and altitude/elevation) to high pr ...
which formed part of the
Global Positioning System
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
. It was the fourth of nine
Block II
Block or blocked may refer to:
Arts, entertainment and media Broadcasting
* Block programming, the result of a programming strategy in broadcasting
* W242BX, a radio station licensed to Greenville, South Carolina, United States known as ''96.3 ...
GPS satellites to be launched, which were the first operational GPS satellites to fly.
Background
It was part of the 21-satellite Global Positioning System (GPS) Block II series that provides precise position data (accurate to within 16 m) to military and civilian users worldwide. Its signals could be received on devices as small as a telephone. The GPS II satellites, built by
Rockwell International
Rockwell International was a major American manufacturing conglomerate involved in aircraft, the space industry, defense and commercial electronics, components in the automotive industry, printing presses, avionics and industrial products. R ...
for the Air Force Space Systems Division, each have a 7.5-year design life. The Air Force intends to launch a GPS II every 2 to 3 months until the constellation of 21 operational satellite and 3 spares is aloft. The GPS Block II join 7 operational Block 1 satellites.
Launch
USA-47 was launched at 09:31:01 UTC on 21 October 1989, atop a
Delta II
Delta II was an expendable launch system, originally designed and built by McDonnell Douglas. Delta II was part of the Delta rocket family and entered service in 1989. Delta II vehicles included the Delta 6000, and the two later Delta 7000 va ...
launch vehicle
A launch vehicle or carrier rocket is a rocket designed to carry a payload (spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pad, launch pads, supported by a missile launch contro ...
, flight number D188, flying in the 6925 configuration.
The launch took place from
Launch Complex 17A (LC-17A) at the
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 statio ...
(CCAFS),
and placed USA-47 into a transfer orbit. The satellite raised itself into
medium Earth orbit
A medium Earth orbit (MEO) is an geocentric orbit, Earth-centered orbit with an altitude above a low Earth orbit (LEO) and below a high Earth orbit (HEO) – between above sea level. using a
Star-37XFP apogee motor
An apogee kick motor (AKM) is a rocket motor that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit into its final (most commonly circular) orbit. For a satellite laun ...
.
Mission
On 21 November 1989, USA-47 was in an orbit with a
perigee
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion.
General description
There are two apsides in any ellip ...
of , an
apogee
An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion.
General description
There are two apsides in any ellip ...
of , a
period
Period may refer to:
Common uses
* Era, a length or span of time
* Full stop (or period), a punctuation mark
Arts, entertainment, and media
* Period (music), a concept in musical composition
* Periodic sentence (or rhetorical period), a concept ...
of 717.9 minutes, and 54.7° of
inclination
Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a Plane of reference, reference plane and the orbital plane or Axis of rotation, axis of direction of the orbiting object ...
to the
equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
.
It operated in slot 5 of plane A of the GPS constellation.
The satellite had a mass of , and generated 710 watts of power.
[ ] It had a design life of 7.5 years,
and ceased operations on 16 March 2001.
References
{{Orbital launches in 1989
GPS satellites
USA satellites
Spacecraft launched in 1989