The end is near: NASA's Kepler space telescope running out of fuel

"Trailing Earth's orbit at 94 million miles away, the Kepler space telescope has survived many potential knock-outs during its nine years in flight, from mechanical failures to being blasted by cosmic rays," NASA announced in a news release Wednesday. "At this rate, the hardy spacecraft may reach its finish line in a manner we will consider a wonderful success."

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Scientists plan to "squeeze every last drop of data from the spacecraft" in its remaining time, but note that without a gas gauge, they only have estimates about how low its fuel is running.

Kepler is expected to run out of fuel and reach its death "within several months."

“It’s like trying to decide when to gas up your car. Do you stop now? Or try to make it to the next station? In our case, there is no next station,” Kepler mission system engineer Charlie Sobeck wrote in the news release.

The Kepler mission, NASA Discovery's 10th mission, first launched in March 2009 with a goal to survey the Milky Way and hunt for Earth-size and smaller planets near the galaxy or "habitable" regions of planets' parent stars.

In 2014, the Kepler space telescope began a new extended mission called K2, which continues the hunt for planets outside our solar system along with its other cosmic tasks.

During this extended mission, the spacecraft was required to shift its field of view to new regions of the sky every three months. This process is called a campaign.

“Initially, the Kepler team estimated that the K2 mission could conduct 10 campaigns with the remaining fuel,” Sobeck wrote. “It turns out we were overly conservative. The mission has already completed 16 campaigns, and this month entered its 17th.”

According to Space.com, "Kepler spots alien worlds by noticing the tiny brightness dips they cause when they cross the face of their host star from the spacecraft's perspective."

Since 2009, Kepler has discovered thousands of exoplanets ranging between Earth-size and Neptune-size (four times the size of Earth).