The Voyager 2 astronomical observatory was launched in 1977
and flew past Neptune in 1989. It transmitted important information about
the planet's rings, moons, and atmosphere. Image credit: World Book illustration
by Oxford Illustrators Limited
|
The National Aeronautics and Space Administration (NASA) launched Voyager 1 on Sept. 5, 1977. The probe made its closest approach to Jupiter on March 5, 1979, encountered Saturn on Nov. 12, 1980, then headed toward interstellar space (the space between the stars). Voyager 2, launched on Aug. 20, 1977, made its closest approach to Jupiter on July 9, 1979, Saturn on Aug. 25, 1981, Uranus on Jan. 24, 1986, and Neptune on Aug. 25, 1989, then traveled toward interstellar space.
The Voyagers carried identical sets of scientific instruments. One instrument measured the strength, shape, and direction of the planets' magnetic fields. Another studied waves traveling through plasma trapped within the fields. Plasma consists of electrically charged atoms as well as electrons that are not parts of atoms.
Three devices measured the quantities and speeds of these charged particles. Five instruments measured ultraviolet rays, visible light, infrared rays, and radio waves given off by the planets and their satellites, rings, and plasma. Also, as the two crafts moved behind each planet, the planet's atmosphere and rings blocked the radio signals transmitted by the Voyagers in ways that revealed details of their structure.
The Voyagers' radio receivers and their particle and magnetism
detectors were still operating in the early 2000's. Scientists monitored their
data in hope of detecting the heliopause, where interstellar space begins.
Scientists suspect that the closest part of this boundary will be found about
9 billion miles (15 billion kilometers) from the sun. One Voyager almost certainly
will reach the heliopause before 2015, when the crafts' radioactively powered
generators run down.
Contributor:
Carolyn Porco, Ph.D., Professor, Cussini Imaging Central Laboratory
for Operations, Southwest Research Institute.
How to cite this article: To cite this article, World Book recommends the
following format:
Porco, Carolyn. "Voyager." World Book Online Reference Center. 2004.
World Book, Inc. http://www.worldbookonline.com/wb/Article?id=ar588865.
› Return to Topics | › Back to Top |