Ranger 2
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Ranger 2 was a flight test of the Ranger spacecraft system of the
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 ...
Ranger program The Ranger program was a series of unmanned space missions by the United States in the 1960s whose objective was to obtain the first close-up images of the surface of the Moon. The Ranger spacecraft were designed to take images of the lunar surf ...
designed for future lunar and
interplanetary mission Interplanetary spaceflight or interplanetary travel is the crewed or uncrewed travel between stars and planets, usually within a single planetary system. In practice, spaceflights of this type are confined to travel between the planets of the ...
s. Ranger 2 was designed to test various systems for future
exploration Exploration refers to the historical practice of discovering remote lands. It is studied by geographers and historians. Two major eras of exploration occurred in human history: one of convergence, and one of divergence. The first, covering most ...
and to conduct scientific observations of
cosmic ray Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...
s,
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 ...
s,
radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...
, dust particles, and a possible
hydrogen gas Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, a ...
"tail" trailing the Earth. National Space Science Data Center, Ranger 2, NSSDC ID: 1961-032A


Spacecraft design

Ranger 2 was of the Ranger Block 1 design and was almost identical to
Ranger 1 Ranger 1 was a prototype spacecraft launched as part of the Ranger program of unmanned space missions. Its primary mission was to test the performance of those functions and parts necessary for carrying out subsequent lunar and planetary missio ...
. The spacecraft consisted of a
hexagonal In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°. Regular hexagon A '' regular hexagon'' has ...
base across, upon which was mounted a cone-shaped 4-meter-high (13.1 ft) tower of aluminum struts and braces. Two
solar panel A solar cell panel, solar electric panel, photo-voltaic (PV) module, PV panel or solar panel is an assembly of photovoltaic solar cells mounted in a (usually rectangular) frame, and a neatly organised collection of PV panels is called a photo ...
wings measuring from tip to tip extended from the base. A high-gain directional
dish antenna A parabolic antenna is an antenna that uses a parabolic reflector, a curved surface with the cross-sectional shape of a parabola, to direct the radio waves. The most common form is shaped like a dish and is popularly called a dish antenna or par ...
was attached to the bottom of the base. Spacecraft experiments and other equipment were mounted on the base and tower. Instruments aboard the spacecraft included a Lyman-alpha telescope, a rubidium-vapor
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 ...
,
electrostatic Electrostatics is a branch of physics that studies electric charges at rest (static electricity). Since classical times, it has been known that some materials, such as amber, attract lightweight particles after rubbing. The Greek word for amber ...
analyzers, medium-energy-range
particle detector In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionizing particles, such as those produced by nuc ...
s, two triple coincidence telescopes, a cosmic-ray integrating
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 ...
,
cosmic dust Cosmic dust, also called extraterrestrial dust, star dust or space dust, is dust which exists in outer space, or has fallen on Earth. Most cosmic dust particles measure between a few molecules and 0.1 mm (100 micrometers). Larger particles are c ...
detectors, and
scintillation counter A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillating material, and detecting the resultant light pulses. It consists of a scintillator w ...
s. The
communications system A communications system or communication system is a collection of individual telecommunications networks, transmission systems, relay stations, tributary stations, and terminal equipment usually capable of interconnection and interoperati ...
included the high-gain
antenna Antenna ( antennas or antennae) may refer to: Science and engineering * Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves * Antennae Galaxies, the name of two collid ...
and an omnidirectional medium-gain antenna and two transmitters at approximately 960 
MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
, one with 0.25  W power output and the other with 3 W power output. Power was to be furnished by 8680
solar cells A solar cell, or photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physics, physical and Chemical substance, chemical phenomenon.silver-zinc battery A silver zinc battery is a secondary cell that utilizes silver(I,III) oxide and zinc. Overview Silver zinc cells share most of the characteristics of the silver-oxide battery, and in addition, is able to deliver one of the highest specific energi ...
, and smaller batteries on some of the experiments. Attitude control was provided by a solid state timing controller,
Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...
and
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
sensors,
gyroscopes A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rotat ...
, and pitch and roll jets. The temperature was controlled passively by gold plating, white paint, and polished
aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
surfaces.


Mission

Shortly after
Ranger 1 Ranger 1 was a prototype spacecraft launched as part of the Ranger program of unmanned space missions. Its primary mission was to test the performance of those functions and parts necessary for carrying out subsequent lunar and planetary missio ...
's unsuccessful mission, Atlas 117D and Agena 6002 were rolled out to LC-12 for the next attempt. Once again, getting the booster and spacecraft ready for flight proved a frustrating experience. On October 24,
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 ...
received the news from the
West Coast of the United States The West Coast of the United States, also known as the Pacific Coast, Pacific states, and the western seaboard, is the coastline along which the Western United States meets the North Pacific Ocean. The term typically refers to the contiguous U.S ...
that a hydraulics failure had prevented Discoverer 33 from reaching orbit the previous day, which necessitated taking Agena 6002 down from the stack and giving it a thorough checkout. The stage was found to have the same problem as Discoverer 33's Agena, necessitating repair work. It took until mid-November before everything was finally ready. Liftoff took place at 3:12 AM EST on November 18. An improper autopilot signal resulted in Atlas BECO taking place 0.4 seconds early. Thus the sustainer phase of flight was initiated with below nominal velocity, but the vehicle reached orbit successfully since the guidance computer was programmed to not issue the SECO command until the proper velocity was achieved. The same malfunction had occurred on Atlas 105D/Midas 4 a month earlier and was traced to the location of the staging backup acceleration switch on the side of the LOX tank, causing the switch to be affected by the super-cold temperatures. The switch was moved to the fuel tank on subsequent Atlas-Agena vehicles. When it came time for the second Agena restart, the result was once again a burn lasting a few seconds. This time, the problem was traced to a defective rate gyro in the Agena which had gone undetected at launch. The control system caused the stage to rotate uncontrollably with the result that the propellants were pushed to the outer edge of the tanks by centrifugal force and could not drain down into the fuel feed lines properly. Unlike with
Ranger 1 Ranger 1 was a prototype spacecraft launched as part of the Ranger program of unmanned space missions. Its primary mission was to test the performance of those functions and parts necessary for carrying out subsequent lunar and planetary missio ...
, the Agena had not operated long enough to achieve any significant ISP and so the probe was left in an even lower orbit. Tracking antennas could not lock onto the probe or send it any commands, nor could the attitude control system stabilize it.
Telemetry Telemetry is the in situ data collection, collection of measurements or other data at remote points and their automatic data transmission, transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Gr ...
and instrument data were still received for a few hours, but eventually the orbit decayed too low and after only one day and 19 orbits, Ranger 2 reentered the
atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
and burned up.


See also

*
Ranger program The Ranger program was a series of unmanned space missions by the United States in the 1960s whose objective was to obtain the first close-up images of the surface of the Moon. The Ranger spacecraft were designed to take images of the lunar surf ...
*
Timeline of Solar System exploration This is a timeline of Solar System exploration ordered by date of spacecraft launch. It includes: *All spacecraft that have left Earth orbit for the purposes of Solar System exploration (or were launched with that intention but failed), includ ...
*
List of artificial objects on the Moon This is a partial list of artificial materials left on the Moon, many during the missions of the Apollo program. The table below does not include lesser Apollo mission artificial objects, such as a hammer and other tools, retroreflectors, Apollo ...


Footnotes


References

*


External links


Space Flight Operations Memorandum - Ranger 2 (Post-flight Mission Analysis)Lunar impact: A history of Project Ranger (PDF) 1977
{{Use American English, date=January 2014 2 Spacecraft launched in 1961 Spacecraft which reentered in 1961