Pioneer 5
Encyclopedia
Pioneer 5 was a spin-stabilized
space probe in the NASA Pioneer program
used to investigate interplanetary space between the orbits of Earth
and Venus
. It was launched on March 11, 1960 from Cape Canaveral Air Force Station
Launch Complex 17a at 13:00:00 UTC with an on-orbit dry mass of 43 kg. It is a 0.66 m diameter sphere
with 1.4 m span across its four solar panels and achieved a solar orbit of 0.806 × 0.995 AU (121,000,000 by 149,000,000 km). Among other accomplishments, the probe confirmed the existence of interplanetary magnetic fields. Pioneer 5 was the most successful probe in the Pioneer/Able missions.
The spacecraft also measured solar flare
particles, and cosmic radiation in the interplanetary region. The micrometeorite counter failed to operate as the data system saturated
and failed to operate properly.
The recorded digital data were transmitted at 1, 8, and 64 bit/s, depending on the distance of the spacecraft from Earth and the size of the receiving antenna. Weight limitations on the solar cell
s prevented continuous operation of the telemetry transmitters. About four operations of 25 min duration were scheduled per day with occasional increases during times of special interest. A total of 138.9 h of operation was completed, and over 3 megabits of data were received. The major portion of the data was received by the Lovell radio telescope
at Jodrell Bank Observatory and the Hawaii Tracking Station
because their antennas provided grid reception. Data was received until April 30, 1960, after which telemetry noise and weak
signal strength made data reception impossible. The spacecraft's signal was detected by Jodrell Bank from a record distance of 36.2 million km (22.5 million miles) on June 26, 1960, although it was much too weak by then to acquire data.
Spin-stabilisation
Spin-stabilisation is the method of stabilizing a satellite or launch vehicle by means of spin. For most satellite applications this approach has been superseded by three-axis stabilisation. It is also used in non-satellite applications such as rifle and artillery.Despinning can be achieved by...
space probe in the NASA Pioneer program
Pioneer program
The Pioneer program is a series of United States unmanned space missions that was designed for planetary exploration. There were a number of such missions in the program, but the most notable were Pioneer 10 and Pioneer 11, which explored the outer planets and left the solar system...
used to investigate interplanetary space between the orbits of Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
and Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
. It was launched on March 11, 1960 from Cape Canaveral Air Force Station
Cape Canaveral Air Force Station
Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...
Launch Complex 17a at 13:00:00 UTC with an on-orbit dry mass of 43 kg. It is a 0.66 m diameter sphere
Sphere
A sphere is a perfectly round geometrical object in three-dimensional space, such as the shape of a round ball. Like a circle in two dimensions, a perfect sphere is completely symmetrical around its center, with all points on the surface lying the same distance r from the center point...
with 1.4 m span across its four solar panels and achieved a solar orbit of 0.806 × 0.995 AU (121,000,000 by 149,000,000 km). Among other accomplishments, the probe confirmed the existence of interplanetary magnetic fields. Pioneer 5 was the most successful probe in the Pioneer/Able missions.
Design and instruments
The spacecraft was a 0.66 m diameter sphere with four solar panels that spanned over 1.4 m. It was equipped with four scientific instruments:- A triple coincidence omnidirectional proportional counter telescope to detect solar particlesSolar Energetic ParticlesSolar Energetic Particles are high-energy particles coming from the Sun which had been first observed in the early 1940s. They consist of protons, electrons and heavy ions with energy ranging from a few tens of keV to GeV...
and observe terrestrial trapped radiation. It could detect photonPhotonIn physics, a photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force...
s with E > 75 MeVElectronvoltIn physics, the electron volt is a unit of energy equal to approximately joule . By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electric potential difference of one volt...
and electronElectronThe electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...
s with E > 13 MeV. - A rotating search coil magnetometerMagnetometerA magnetometer is a measuring instrument used to measure the strength or direction of a magnetic field either produced in the laboratory or existing in nature...
to measure the magnetic fieldMagnetic fieldA magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
in the distant field of the Earth, near the geomagnetic boundary, and in interplanetary space. It was capable of measuring fields from 1 microgaussGauss (unit)The gauss, abbreviated as G, is the cgs unit of measurement of a magnetic field B , named after the German mathematician and physicist Carl Friedrich Gauss. One gauss is defined as one maxwell per square centimeter; it equals 1 tesla...
to 12 milligauss. It consisted of a single search coil that was mounted on the spacecraft in such a way that is measured the magnetic field perpendicular to the spin axis of the spacecraft. It could output its measurements in both an analog and a digital format. - A Neher-type integrating ionization chamberIonization chamberThe ionization chamber is the simplest of all gas-filled radiation detectors, and is used for the detection or measurement of ionizing radiation...
and an Anton 302 Geiger-Müller tubeGeiger-Müller tubeA Geiger–Müller tube is the sensing element of a Geiger counter instrument that can detect a single particle of ionizing radiation, and typically produce an audible click for each. It was named for Hans Geiger who invented the device in 1908, and Walther Müller who collaborated with Geiger in...
(which functioned as a cosmic rayCosmic rayCosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...
detector) to measure cosmic radiation. It was mounted normal to the spin axis of the spacecraft. - A micrometeoriteMicrometeoroidA micrometeoroid is a tiny meteoroid; a small particle of rock in space, usually weighing less than a gram. A micrometeor or micrometeorite is such a particle that enters the Earth's atmosphere or falls to Earth.-Scientific interest:...
momentumMomentumIn classical mechanics, linear momentum or translational momentum is the product of the mass and velocity of an object...
spectrometer (or micrometeorite detector) that consisted of two diaphragmDiaphragm (acoustics)In the field of acoustics, a diaphragm is a transducer intended to faithfully inter-convert mechanical motion and sound. It is commonly constructed of a thin membrane or sheet of various materials. The varying air pressure of the sound waves imparts vibrations onto the diaphragm which can then be...
and microphoneMicrophoneA microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...
combinations. It was used to measure the amount of meteoritic dust particles and the momentum of these particles.
Mission
The spacecraft returned data collected by the magnetometer on the magnetic field and it measured that the median undisturbed interplanetary field was approximately 5 γ ± 0.5 γ in magnitude.The spacecraft also measured solar flare
Solar flare
A solar flare is a sudden brightening observed over the Sun surface or the solar limb, which is interpreted as a large energy release of up to 6 × 1025 joules of energy . The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach Earth a day...
particles, and cosmic radiation in the interplanetary region. The micrometeorite counter failed to operate as the data system saturated
Saturation
Saturation or saturated may refer to:- Meteorology :* Dew point, which is a temperature that occurs when atmospheric humidity reaches 100% and the air is saturated with moisture- Physics :...
and failed to operate properly.
Solar cell
A solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect....
s prevented continuous operation of the telemetry transmitters. About four operations of 25 min duration were scheduled per day with occasional increases during times of special interest. A total of 138.9 h of operation was completed, and over 3 megabits of data were received. The major portion of the data was received by the Lovell radio telescope
Lovell Telescope
The Lovell Telescope is a radio telescope at Jodrell Bank Observatory, near Goostrey, Cheshire in the north-west of England. When it was constructed in 1955, the telescope was the largest steerable dish radio telescope in the world at 76.2 m in diameter;it is now the third largest, after the...
at Jodrell Bank Observatory and the Hawaii Tracking Station
Kaena Point Satellite Tracking Station
The Kaena Point Satellite Tracking Station is a United States Air Force military installation in Kaena Point on the island of Oahu in Hawaii. It is a remote tracking station of the Air Force Satellite Control Network responsible for tracking satellites in orbit, many of which support the United...
because their antennas provided grid reception. Data was received until April 30, 1960, after which telemetry noise and weak
Weak
Weak is a generic adjective pertaining to a general state of feebleness, a lack of strength, durability, or vigor.- Music :* "Weak" , a song by SWV* "Weak" , a song by Skunk Anansie...
signal strength made data reception impossible. The spacecraft's signal was detected by Jodrell Bank from a record distance of 36.2 million km (22.5 million miles) on June 26, 1960, although it was much too weak by then to acquire data.
See also
- Pioneer programPioneer programThe Pioneer program is a series of United States unmanned space missions that was designed for planetary exploration. There were a number of such missions in the program, but the most notable were Pioneer 10 and Pioneer 11, which explored the outer planets and left the solar system...