Yea, its definitely a setback, but luckily the work its already done is saved, so we dont need to start from scratch when the next one goes up.It's not just that we're blind for a few years. It's that to confirm Earth-like planets around Sun-like stars, it was imperative that it last another year or two. It needs to see at least 3 transits before it can confirm a planet candidate, and it will fall short of that for Earth-like planets/orbits.
Totally dependent on the type of star it is orbiting. And my understanding is that it was just short of the time required to observe a planet like Earth orbiting a Sun-like star three times, but perhaps I'm wrong on that. From the New Scientist article I posted before:What is the expected range of orbital period for planets with liquid water? Running four years, Kepler would have caught Mercury, Venus, Earth and two occurrences of Mars (10% chance of 3 occurrences) in our solar system. Sounds pretty good to me!
Near as I can tell, it's been up there and observing for 4 years, with some windows where it was in safe mode. So I'm not sure why exactly it was short on time.Still, if Kepler cannot be brought back into action, the timing will be tragic for scientists hoping to realise the mission's primary goal: determining what fraction of sun-like stars host Earth-sized planets with temperatures favourable for life.
Astronomers need to see at least three transits to confirm a signal as an orbiting planet. That means planets farther from their stars, in the habitable "Goldilocks zone" - in which a planet's surface temperature is just right for liquid water to exist - will take longer to find. Kepler needs a few more years' worth of data to see planets around sun-like stars with orbits that last longer than 200 days, says exoplanet researcher Sara Seager of the Massachusetts Institute of Technology.
"It will mean that the mission won't confirm as many small planets in the habitable zone as had been hoped," says Fabrycky. "It's a real loss."