Ranger 1
Encyclopedia
Ranger 1 was a spacecraft in 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 missions; a secondary objective was to study the nature of particles and fields in interplanetary space. The spacecraft was only partially successful, due to failure of a rocket late in the mission.
across upon which was mounted a cone-shaped 4 m high tower of aluminum struts and braces. Two solar panel wings measuring 5.2 m from tip to tip extended from the base. A high-gain directional dish antenna 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
, electrostatic analyzers, medium-energy range particle detectors, two triple coincidence telescopes, a cosmic-ray integrating ionization chamber
, cosmic dust detectors, and solar X-ray scintillation counter
s.
The communications system included the high gain antenna and an omni-directional medium gain antenna and two transmitters, one at 960.1 MHz with 0.25 W
power output and the other at 960.05 MHz with 3 W power output. Power was to be furnished by 8680 solar cells on the two panels, a 57 kg silver-zinc battery, and smaller batteries on some of the experiments. Attitude control was provided by a solid-state timing controller, Sun
and Earth
sensors, and pitch and roll jets. The temperature was controlled passively by gold plating, white paint, and polished aluminum surfaces.
and then move into a 60,000 by 1,100,000 km Earth orbit. The purpose was to test systems and strategies for future lunar missions.
and began tumbling. The satellite re-entered Earth's atmosphere on August 30, 1961. The mission was partially successful, in that much of the primary objective of flight testing the equipment was accomplished; however, little scientific data was returned.
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 surface, returning those images until they were destroyed...
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 missions; a secondary objective was to study the nature of particles and fields in interplanetary space. The spacecraft was only partially successful, due to failure of a rocket late in the mission.
Spacecraft design
The spacecraft was of the Ranger Block 1 design and consisted of a hexagonal base 1.5 mMetre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
across upon which was mounted a cone-shaped 4 m high tower of aluminum struts and braces. Two solar panel wings measuring 5.2 m from tip to tip extended from the base. A high-gain directional dish antenna 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
Magnetometer
A 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...
, electrostatic analyzers, medium-energy range particle detectors, two triple coincidence telescopes, a cosmic-ray integrating ionization chamber
Ionization chamber
The ionization chamber is the simplest of all gas-filled radiation detectors, and is used for the detection or measurement of ionizing radiation...
, cosmic dust detectors, and solar X-ray scintillation counter
Scintillation counter
A scintillation counter measures ionizing radiation. The sensor, called a scintillator, consists of a transparent crystal, usually phosphor, plastic , or organic liquid that fluoresces when struck by ionizing radiation. A sensitive photomultiplier tube measures the light from the crystal...
s.
The communications system included the high gain antenna and an omni-directional medium gain antenna and two transmitters, one at 960.1 MHz with 0.25 W
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
power output and the other at 960.05 MHz with 3 W power output. Power was to be furnished by 8680 solar cells on the two panels, a 57 kg silver-zinc battery, and smaller batteries on some of the experiments. Attitude control was provided by a solid-state timing controller, Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
and 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...
sensors, and pitch and roll jets. The temperature was controlled passively by gold plating, white paint, and polished aluminum surfaces.
Design
The Ranger 1 spacecraft was designed to go into an Earth parking orbitParking orbit
A parking orbit is a temporary orbit used during the launch of a satellite or other space probe. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory...
and then move into a 60,000 by 1,100,000 km Earth orbit. The purpose was to test systems and strategies for future lunar missions.
Delay of the launch
- Delay of the 1st countdown
- July 26: Trajectory information required by the Range Safety Officer was delayed.
- July 27: A guidance system malfunction in the Atlas booster.
- July 28: Engineers found that the guidance program to be fed into the Cape computer contained an error.
- 1st countdown. July 29.
- 83 minutes before launch: Power interruptions occurred, requiring momentary holds to permit all stations to check and recover.
- 28 minutes before launch: Commercial electrical power failed. Inadequate allowance had been made for changes in cable sag caused by variations in temperature on the new power poles recently installed at Cape Canaveral Air Force StationCape Canaveral Air Force StationCape 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...
.
- 2nd countdown. July 30. Engineers discovered a leak in Ranger's attitude control gas system.
- 3rd countdown. July 31. A valve malfunctioned in the liquid-oxygen tank on the Atlas booster.
- 4th countdown. August 1. Ground controllers turned on a spacecraft command applying high voltage to the scientific experiments for calibration purposes. Immediately all stations reported a major spacecraft failure. An electrical malfunction had triggered multiple commands from the central clock timer, and Ranger 1 "turned on" as it had been programmed to do in orbit. The explosive squibs fired, solar panels extended inside the shroud, and all the experiments commenced to operate. Project engineers disengaged Ranger 1 from the Agena and hastily returned it to Hangar AE. Meantime the launch was rescheduled for August 22, the next available opportunity. Subsequent tests and investigations determined the activating mechanism to have been a voltage discharge to the spacecraft frame; although engineers suspected one or two of the scientific instruments, they could not determine the precise source of the discharge with certainty. In the days that followed they replaced and requalified the damaged parts, and modified the circuitry to prevent a recurrence of this kind of failure.
Launch
In the evening of August 22, 1961, Ranger 1 was successfully launched into the parking orbit as planned. However, its Agena B engine failed to restart to put it into the higher trajectory orbit, so that when Ranger 1 separated from its Agena stage it went into a low Earth orbitLow Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
and began tumbling. The satellite re-entered Earth's atmosphere on August 30, 1961. The mission was partially successful, in that much of the primary objective of flight testing the equipment was accomplished; however, little scientific data was returned.