William Atkins
Sunday, 01 March 2009 20:13
Science -
Space
Page 2 of 3
Pioneer 4 was very small in size when compared to space probes of today. It only stood 51 centimeters (about 1.7 feet) high at its base and only 23 centimeters (about nine inches) in diameter.
The NASA probe carried a lunar radiation environment experiment, which used a Geiger-Müller tube detector (two Geiger counters) and a lunar photography experiment.
When the little cone-shaped, battery-powered probe passed by the Moon—doing so at a closest distance of about 59,545 kilometers (about 37,300 miles)—its photoelectric sensor, which sensed radiation (light) coming off the Moon, did not detect any radiation coming off of the Moon.
[Remember that light (also called radiation) does not only mean visible light but also the other types of radiation within the electromagnetic spectrum such as radio, microwave, infrared (IR), visible, ultraviolet (UV), x-ray, and gamma ray.]
Pioneer 4 passed the lunar surface at its closest approach on March 4, 1959 at 22:25 UTC (5:25 p.m. Eastern Standard Time [EST]) at a speed of 7,230 kilometers per hour.
It completed its primary mission by successfully achieving an Earth-Moon trajectory (in preparation for sending humans to the Moon in the 1960s).
Its secondary mission was also successfully completed: returning lunar radiation data back to scientists on Earth and providing telemetry (tracking) data back to ground controllers on Earth (also in preparation for sending Apollo astronauts to the Moon).
Pioneer 4 failed in one aspect. Please read page 3 to find out its one problem.
