A Satellite Change of Duties in Orbit
A 21st Century Satellite Orbiting Earth
One satellite actually was changed in space from near-Earth physics researcher to astronomer.
Among the dozens of Explorer spacecraft launched over the decades by the United States was the International Comet Explorer (ICE).
However, it wasn't launched as the International Comet Explorer, but as the third International Sun-Earth Explorer -- a solar observatory sent up by NASA in 1978 to a halo orbit at the Earth-Sun libration point where the pull of gravity from Earth and Sun are equal. Hanging about a million miles from Earth toward the Sun, ISEE-3 warned of solar flares before magnetic disturbances reached Earth.
That is, until the Comet Giacobini-Zinner was found rushing to pass Earth in September 1985. NASA quickly renamed ISEE-3 to ICE and pointed it toward the in-rushing comet.
Giacobini-Zinner wasn't to be ICE's last encounter with a comet. Just six months later in March 1986, the satellite was turned again. This time, ICE was pointed at the famous Comet Halley making its 76-year trek through the Solar System.
ICE observed Comet Halley from a distance of 17 million miles, sending home a wealth of information about that sooty, potato-shaped rock as big as a mountain flying around the Sun.
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