By gauging the subtle differences in light given off by a planet 1,000 light-years away, it shows that it's up to the job.
The test run clearly demonstrates that Kepler will have little trouble performing its primary mission: detecting Earth-like planets in the habitable zones of sun-like stars.
In the process, Kepler has given astronomers a detailed look at the planet – its temperature and how its atmosphere operates.
The Kepler team was confident that their spacecraft would be able to achieve its main goal. But nothing substitutes for checking the observatory out on orbit to be sure.
"We now know that Kepler can do it," Dr. Boss said during a briefing Thursday afternoon at NASA headquarters. "The question that remains is: How many Earths are out there for Kepler to find?"
Scientists have become adept at finding planets by measuring how starlight dims when planets pass in front of their suns – an occurrence called a transit. But that method has favored finding large planets that can dim the light of their star significantly. To see Earth-size planets, Kepler must be able to detect much more subtle changes – which is what it demonstrated in its study of the large planet dubbed HAT-P-7b.