Mariner 4
The Mariner 4 spacecraft
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| Mission type | Mars flyby |
|---|---|
| Operator | NASA / JPL |
| COSPAR ID | 1964-077A |
| SATCAT № | 942 |
| Mission duration | 3 years, 23 days |
| Spacecraft properties | |
| Manufacturer | Jet Propulsion Laboratory |
| Launch mass | 260.8 kilograms (575 lb) |
| Power | 310 watts (at Mars encounter) |
| Start of mission | |
| Launch date | November 28, 1964, 14:22:01 UTC |
| Rocket | Atlas LV-3 Agena-D |
| Launch site | Cape Canaveral LC-12 |
| End of mission | |
| Last contact | December 21, 1967 |
| Orbital parameters | |
| Reference system | Heliocentric |
| Semi-major axis | 199,591,220 kilometers (124,020,230 mi) |
| Eccentricity | 0.17024754 |
| Perihelion | 165,611,300 kilometers (102,906,100 mi) |
| Apohelion | 233,571,130 kilometers (145,134,370 mi) |
| Inclination | 2.51 degrees |
| Period | 562.888 days |
| Flyby of Mars | |
| Closest approach | July 15, 1965, 01:00:57 UTC |
| Distance | 9,846 kilometers (6,118 miles) |
| Instruments | |
| Cosmic dust detector Cosmic ray telescope Geiger counter/ionization chamber Helium magnetometer Solar plasma probe Trapped radiation detector TV camera |
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Mariner 4 (together with Mariner 3 known as Mariner–Mars 1964) was the fourth in a series of spacecraft intended for planetary exploration in a flyby mode. It was designed to conduct closeup scientific observations of Mars and to transmit these observations to Earth. Launched on November 28, 1964, Mariner 4 performed the first successful flyby of the planet Mars, returning the first pictures of the Martian surface. It captured the first images of another planet ever returned from deep space; their depiction of a cratered, seemingly dead world largely changed the view of the scientific community on life on Mars. Other mission objectives were to perform field and particle measurements in interplanetary space in the vicinity of Mars and to provide experience in and knowledge of the engineering capabilities for interplanetary flights of long duration. On December 21, 1967 communications with Mariner 4 were terminated.
The Mariner 4 spacecraft consisted of an octagonal magnesium frame, 127 cm across a diagonal and 45.7 cm high. Four solar panels were attached to the top of the frame with an end-to-end span of 6.88 meters, including solar pressure vanes which extended from the ends. A 116.8 cm diameter high-gain parabolic antenna was mounted at the top of the frame as well. An omnidirectional low-gain antenna was mounted on a seven foot, four inch (223.5 cm) tall mast next to the high-gain antenna. The overall height of the spacecraft was 2.89 meters. The octagonal frame housed the electronic equipment, cabling, midcourse propulsion system, and attitude control gas supplies and regulators.
The scientific instruments included:
The electrical power for the instruments and the radio transmitter of Mariner 4 was supplied by 28,224 solar cells contained in the four 176 x 90 cm solar panels, which could provide 310 watts at the distance of Mars. A rechargeable 1200 W·h silver-zinc battery was also used for maneuvers and backup. Monopropellant hydrazine was used for propulsion, via a four-jet vane vector control motor, with 222-newton (50 lbf) thrust, installed on one of the sides of the octagonal structure. The space probe's attitude control was provided by 12 cold nitrogen gas jets mounted on the ends of the solar panels and three gyros. Solar pressure vanes, each with an area of 0.65 square meter (seven ft²), were attached to the tips of the solar panels. Positional information was provided by four Sun sensors, and a sensor for either the Earth, Mars, or the star Canopus, depending on the time in its spaceflight. Mariner 4 was the first space probe that needed a star for a navigational reference object, since earlier missions, which remained near either the Earth, the Moon, or the planet Venus, had sighted onto either the bright face of the home planet or the brightly lit target. During this flight, both the Earth and Mars would be too dim to lock onto. Another bright source at a wide angle away from the Sun was needed and Canopus filled this requirement. Subsequently, Canopus was used as a reference point in many following missions.
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