The End Is Coming For Kepler

As of right now, we have discovered close to 4,000 extrasolar planets. That's an impressive haul for a science that's only 25 years old. We owe the vast majority of those discoveries to one space probe, the Kepler Space Telescope. For 9 years it's been patiently watching a narrow cone of the sky, watching for dips of light in the thousands of stars within its line of sight, a surefire sign of the present of an orbiting planet. It's been spectacularly successful, discovering thousands of worlds, some of which are potentially Earth-like.

Kepler is also nearly out of fuel. On August 2, Kepler will turn its antenna towards Earth to send back its latest batch of data, and it is likely that this will burn all the remaining fuel. There may be enough for one more 80-day period of data collection, but almost certainly no more after that. Kepler's been running on fumes for months. Unlike something like Hubble, which is in low Earth orbit and can be regularly serviced, Kepler is millions of miles away in a solar orbit and far beyond our ability to refuel it. When it's done, it's done forever. There are other space probes out there currently hunting for exoplanets, but for sheer output, I don't imagine anything will be matching Kepler any time soon.