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Two space-based satellite missions have been designed for this purpose. Kepler is a NASA project which has been studied by David Koch and his collaborators. It was designed to continuously and simultaneously monitor 8.500 Sun-like stars for transit events. The scientists behind the mission had used data from the *** Active Cavity Radiometer for Irradiance Minitoring (ACRIM 1)*** abroad the Solar Maximum Satellite, in order to show that the Sun was photometrically stable between periods of 4 to 12 hours. This was essential because, assuming the Sun is typical of G-type stars, it means that variability on the stellar surfaces will not swamp the decreases in the brightness caused by transit events. Using the ACRIM data they have constructed the typical light curves that would be expected from a Sun-like star with an Earth-like planet in orbit (see Figure 9.3.). Unfortunately, in April 1997 NASA decided not to fund the Kepler mission at the present time, but did not preclude it from being funded in the near future. However, a very similar French mission called COROT, to be funded by the CNES, will launch in the early 2000s.