The Solar and Heliospheric Observatory (SOHO) spacecraft is
expected to discover its 1,000TH comet this summer. The SOHO
spacecraft is a joint effort between NASA and the European Space
Agency. It has accounted for approximately one-half of all comet
discoveries with computed orbits in the history of astronomy.
"Before SOHO was launched, only 16 sun grazing comets had been
discovered by space observatories. Based on that experience, who
could have predicted SOHO would discover more than 60 times that
number, and in only nine years," said Dr. Chris St. Cyr. He is
senior project scientist for NASA's Living With a Star program
at the agency's Goddard Space Flight Center, Greenbelt, Md.
"This is truly a remarkable achievement!" About 85 percent of
the comets SOHO discovered belongs to the Kreutz group of sun
grazing comets, so named because their orbits take them very
close to Earth's star. The Kreutz sun grazers pass within
500,000 miles of the star's visible surface. Mercury, the planet
closest to the sun, is a