Pioneer 4

Pioneer 4
The non-started copy of Pioneer 4
NSSDC ID	1959-013A
Mission goal	Images of the lunar surface
Client	NASA
Launcher	Juno II (5-stage)
Instruments
Trapped Radiation Experiment u. A.
Course of the mission
Start date	March 3, 1959, 17:11 UTC
launch pad	CCAFS , LC-5
03.03.1959 17:11 begin 03/04/1959 10:25 PM Closest approach to the moon 03/18/1959 1:00 AM First perihelion The probe is in a heliocentric orbit

Pioneer 4 is a space probe from the US space agency NASA as part of the Pioneer program. Pioneer 4 should fly past the moon and transmit images of the lunar surface.

construction

Pioneer 4 consists of a conical fiberglass structure 51 cm high and 23 cm in diameter, the tip of which is designed as an antenna, making it slightly smaller than its predecessor. The outside is gold-plated to make it electrically conductive and has white stripes for thermal control. The probe was powered by mercury batteries and carries a transmitter with a power of 0.18 W at 960.05 MHz. To reduce the spin rate from 400 / min to 6 / min, two disposable masses of 7 g each (“yo-yo masses”) are attached to the outside.

mission

Pioneer 4 was on March 3, 1959 two months after the Soviet Union with Luna 1 already the first flyby , had succeeded at the moon through a four-step Juno II rocket launched. The probe should pass the moon and go into heliocentric orbit. It reached a course to the moon and delivered the desired radiation readings, but the approximate 60,000 km approach to the moon was not enough to trigger the camera equipped with a light sensor. The probe worked a total of 82.5 hours to a distance of 658,000 km. Since then, like the fourth stage of Juno II, it has been in a solar orbit with a slightly higher orbital period than Earth.

Web links

Commons : Pioneer (space probe program)  - collection of images, videos and audio files

• Pioneer 4 - NASA Jet Propulsion Laboratory (English)
• Pioneer 4 - National Space Science Data Center (English)
• Description of the Pioneer 4 mission on nasa.gov/Solar System Exploration (English)

Individual evidence

1. ↑ Jet Propulsion Laboratory (under contract for NASA ): The Moon Probe Pioneer IV. (PDF) NASA-JPL, 1959, accessed on February 2, 2008 (English).