Pioneer 1 (also known as Able 2)
was an American
space probe
A space probe is an artificial satellite that travels through space to collect scientific data. A space probe may orbit Earth; approach the Moon; travel through interplanetary space; flyby, orbit, or land or fly on other planetary bodies; or ent ...
, the first under the auspices of
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
, which was launched by a
Thor-Able
The Thor-Able was an American expendable launch system and sounding rocket used for a series of re-entry vehicle tests and satellite launches between 1958 and 1960. It was a two-stage rocket, consisting of a Thor IRBM as a first stage and a Vang ...
rocket on 11 October 1958. It was intended to
orbit the Moon and make scientific measurements, but due to a guidance error failed to achieve lunar orbit and was ultimately destroyed upon reentering Earth's atmosphere. The flight, which lasted 43 hours and reached an apogee of 113,800 km (70,700 miles), was the second and most successful of the three Thor-Able space probes.
Spacecraft design
![Pioneer I on the Launch Pad - GPN-2002-000204](https://upload.wikimedia.org/wikipedia/commons/0/07/Pioneer_I_on_the_Launch_Pad_-_GPN-2002-000204.jpg)
Pioneer 1 was fabricated by Space Technology Laboratories, a division of Ramo-Wooldridge Corp (later
TRW Inc.
TRW Inc., was an American corporation involved in a variety of businesses, mainly aerospace, electronics, automotive, and credit reporting.http://www.fundinguniverse.com/company-histories/TRW-Inc-Company-History.html TRW Inc. It was a pioneer ...
),
"Pioneering Space”
/ref> and consisted of a thin cylindrical midsection with a squat truncated cone on each side. The cylinder was in diameter and the height from the top of one cone to the top of the opposite cone was . Along the axis of the spacecraft and protruding from the end of the lower cone was an solid propellant injection rocket and rocket case, which formed the main structural member of the spacecraft. Eight small low-thrust solid propellant
A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or other motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicles, the e ...
velocity adjustment rockets were mounted on the end of the upper cone in a ring assembly which could be jettisoned after use. A magnetic dipole antenna
In radio and telecommunications a dipole antenna or doublet is the simplest and most widely used class of antenna. The dipole is any one of a class of antennas producing a radiation pattern approximating that of an elementary electric dipole w ...
also protruded from the top of the upper cone. The shell was composed of laminated plastic. The total mass of the spacecraft after vernier separation was , after injection rocket firing it would have been .
The three-stage Thor-Able vehicle consisted of a modified Air Force Thor IRBM (liquid propellant, thrust about ) as the first stage. A liquid-propellant rocket
A liquid-propellant rocket or liquid rocket utilizes a rocket engine that uses liquid rocket propellant, liquid propellants. Liquids are desirable because they have a reasonably high density and high Specific impulse, specific impulse (''I''sp). T ...
engine powered the second stage (modified Vanguard second stage, thrust about ). The third stage was a solid-propellant unit based on Vanguard design, rated at -sec total impulse
Impulse or Impulsive may refer to:
Science
* Impulse (physics), in mechanics, the change of momentum of an object; the integral of a force with respect to time
* Impulse noise (disambiguation)
* Specific impulse, the change in momentum per uni ...
.
The scientific instrument package had a mass of and consisted of an image scanning infrared television system to study the Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
's surface to a resolution of 0.5°, an ionization chamber
The ionization chamber is the simplest type of gas-filled radiation detector, and is widely used for the detection and measurement of certain types of ionizing radiation, including X-rays, gamma rays, and beta particles. Conventionally, the term ...
to measure radiation in space, a diaphragm/microphone assembly to detect micrometeorites
A micrometeorite is a micrometeoroid that has survived atmospheric entry, entry through the atmosphere of Earth, Earth's atmosphere. Usually found on Earth's surface, micrometeorites differ from meteorites in that they are smaller in size, more a ...
, a spin-coil magnetometer
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...
to measure magnetic fields to 5 microgauss, and temperature-variable resistor
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active el ...
s to record the spacecraft's internal conditions. The spacecraft was powered by nickel-cadmium batteries for ignition of the rockets, silver cell batteries for the television system, and mercury batteries for the remaining circuits. The radio transmission was on 108.06 MHz through an electric dipole antenna for telemetry and doppler information at 300 mW and a magnetic dipole antenna for the television system at 50 W. Ground commands were received through the electric dipole antenna at 115 MHz. The spacecraft was spin-stabilized at 1.8 rps, the spin direction was approximately perpendicular to the geomagnetic meridian planes of the trajectory.
Mission
Two days after the failure of Pioneer 0 on 17 August 1958, Thor 129, the backup vehicle, was erected on LC-17B in preparation for a September attempt. The postflight investigation of Pioneer 0 pointed to a turbopump failure, which had also caused the loss of Thor-Able 116 in April. This was followed by the failure of an Atlas launch on 18 September, so the Air Force moved to replace the turbopumps in their inventory of Thor and Atlas missiles. Thor 129 was pulled from the pad for modifications and replaced with Thor 130.
On 11 October 1958, Pioneer 1 lifted off smoothly, but the guidance system steered the Thor slightly too high and fast, causing the second stage to be lofted 3° higher than intended. As a result, it shut off 10 seconds earlier than planned, and also bumped the third stage during separation. The third stage was left pitched up about 15° and suffering a velocity shortfall of about 500 feet per second. The vernier engines on the third stage were fired to make up for the thrust deficit, but added only 150 feet per second of velocity, insufficient to escape Earth orbit. As a last resort, ground controllers decided that if they could not get Pioneer 1 to the Moon, they would place it in a high Earth orbit by firing the attached solid rocket motor. The inaccurate launch trajectory, however, had placed the probe on an orbital track that resulted in thermal heating and cooling beyond what the primitive temperature control system could handle. The probe's internals fell to near-freezing temperatures, rendering the solid motor igniter inoperable. Pioneer 1 reached a total distance of before beginning its descent back to Earth.
The spacecraft was launched from LC-17A at Cape Canaveral at 08:42:00 GMT but it did not reach the Moon as planned due to a programming error in the upper stage causing a slight error in burnout velocity and angle (3.5°). This resulted in a ballistic trajectory with a peak altitude of around 13:00 local time. The real-time transmission was obtained for about 75% of the flight, but the percentage of data recorded for each experiment was variable. Except for the first hour of flight, the signal-to-noise ratio was good. The spacecraft ended transmission when it reentered the Earth's atmosphere after 43 hours of flight on 13 October 1958 at 03:46 GMT over the South Pacific Ocean
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
. A small quantity of useful scientific information was returned, showing the radiation surrounding Earth was in the form of bands and measuring the extent of the bands, mapping the total ionizing flux, making the first observations of hydromagnetic oscillations of the magnetic field
A magnetic field is a vector 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 to its own velocity and to ...
, and taking the first measurements of the density of micrometeorites and the interplanetary magnetic field
The interplanetary magnetic field (IMF), now more commonly referred to as the heliospheric magnetic field (HMF), is the component of the solar magnetic field that is dragged out from the solar corona by the solar wind flow to fill the Solar Syst ...
.
See also
* Pioneer program
The Pioneer programs were two series of United States lunar and planetary space probes exploration. The first program, which ran from 1958 to 1960, unsuccessfully attempted to send spacecraft to orbit the Moon, successfully sent one spacecraft to ...
References
External links
''United States Space Program Progress 1958''
discusses Pioneer 0 - 3 at YouTube
Space Technology Laboratories Documents Archive
Richard Kruse
{{TRW
Spacecraft launched in 1958
Missions to the Moon
Pioneer 01
Spacecraft which reentered in 1958
TRW Inc.
October 1958 events in the United States