Europe's Rosetta craft swoops in close to comet it's been chasing, altitude under 4 miles

The European Space Agency has sent its Rosetta probe in for a close look at the comet it's been tracking for months, a swoop that scientists hope will provide them with detailed measurements and photos of its surface.

ESA tweeted that Rosetta passed just 6 kilometers (less than 4 miles) above the surface of comet 67P/Churyumov-Gerasimenko Saturday. It's expected to return images by Monday.

Rosetta has been flying alongside the comet since August and recently orbited at an altitude of around 26 kilometers (16 miles).

Rosetta in November released the Philae lander to the comet's surface. Philae returned reams of data before depleted batteries silenced it.

Mission controllers want to pin down Philae's location on the comet and hope its solar panel-powered battery will recharge as it nears the sun.