The Kepler space telescope was launched in 2009 and was only intended to operate for three and a half years, but NASA scientists were able to come up with workarounds to enable them to keep gathering data from the telescope for nearly a decade. But NASA announced last year that the craft was finally out of fuel and would no longer be able to orient itself towards Earth, meaning that it would not be able to send any more data back.
Before the telescope ended its story, however, it sent back one last image to Earth as part of its planet-hunting mission. In its last year, Kepler found a large Earth-like world that was twice the size of our planet as well as a super Earth and a planet similar to Saturn which orbited a star like our Sun. And finally, it sent back this “last light” image that draws this remarkable journey to a close.
This image was taken in the direction of the Aquarius constellation and includes the TRAPPIST-1 system which has seven planets, at least three of which are thought to be temperate. Also captured was the GJ 9827 system, whose bright star illuminates nearby planets which could be good targets for future telescope observations. The gaps in the image are due to camera parts which failed earlier in Kepler’s life, but thanks to its modular design the rest of the instrument was able to continue gathering data.
In a neat bookend to Kepler’s story, its final field of view overlaps with that of its successor, the Transiting Exoplanet Survey Satellite (TESS). TESS will be taking up the baton of planet hunting, and having two sets of data about the same area of space allows researchers to find anything they might have missed and to improve their understanding of the data.
This is goodbye for Kepler, but it leaves behind a remarkable scientific legacy — a trove of astronomical data collected over its decade-long mission, all of which is available to the public for download.