Hipparcos
Full Name: Hipparcos
Phase: Past
Launch Date: August 08, 1989
Mission Project Home Page: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=20
Hipparcos was the first space mission dedicated to measuring the positions, distances, motions, brightness and colors of stars - for astrometry, as the experts call it.
Launched in August 1989 Hipparcos was a pioneering space experiment
dedicated to the precise measurement of the positions, parallaxes and
proper motions of the stars. The intended goal was to measure the five
astrometric parameters of some 120,000 primary programm stars to a
precision of some 2 to 4 milliarcsec, over a planned mission lifetime
of 2.5 years, and the astrometric and two-colour photometric properties
of some 400 000 additional stars (the Tycho experiment) to a somewhat
lower astrometric precision.
Having achieved the mission goals, communications with Hipparcos were terminated in August 1993. NASA provided some critical support to the mission.
Hipparcos helped to:
- predict the impacts of Comet Shoemaker-Levy 9 on Jupiter
- identified stars that will pass close to the Sun
- established the distances of stars possessing planets
- discovered that the Milky Way is changing shape
- identified a group of stars that invaded our Galaxy when it was young
- altered the cosmic distance scale, making the Universe bigger and younger
- confirmed Einstein's prediction of the effect of gravity on starlight