Kepler Space Telescope Resumes Planet-Hunting Mission After Being Stuck in Emergency Mode

— -- NASA's Kepler space probe has resumed its hunt for exoplanets, following a scare earlier this month that put the entire science mission in jeopardy.

The space probe resumed its science mission at 11:30 a.m. ET today, according to Charlie Sobeck, Kepler mission manager.

"The Kepler and K2 missions have been a rewarding job for everyone involved, but there’s a special satisfaction to responding well to an emergency like this," Sobeck said in a statement.

Engineers discovered a few weeks ago that Kepler was operating in emergency mode, forcing it to burn more of its precious fuel supply. Kepler needs its fuel to ignite its thrusters and also to orient the spacecraft so it is able to check-in with the Kepler team on Earth.

Kepler entered emergency mode 14 hours before it was set to orient itself toward the center of the Milky Way for a gravitational microlensing study that would allow it to potentially detect extremely distant planets by using the gravity of massive objects, such as stars and planets, and studying its effect on other nearby objects.

NASA engineers are now examining a trove of data to determine the cause of the near shutdown.

This was not the first issue for Kepler, which launched in 2009. Two of the reaction wheels that allow the spacecraft to orient itself stopped working in 2013. Since then, Kepler has been operating in K2 mode, which makes up for the loss of the wheels by leveraging pressure from sunlight.

Despite the glitches, Kepler has had tremendous success in space; NASA says Earth 2.0 may soon be discovered.

Last year, NASA announced it had located a planet and star closely resembling Earth and the sun. The newly discovered planet, which NASA has named Kepler-452b, is believed to be 6 billion years old -- making it about 1.5 billion years older than the Earth and sun. NASA said the star, Kepler-452, also has the same temperature as the sun and a diameter 10 percent larger.

What makes the discovery especially intriguing is that the planet is orbiting the habitable zone of the solar system, the "Goldilocks" region where it's not too hot nor too cold, so that the surface of the planet could, in theory, sustain liquid water.

During its prime mission, which ended in 2012, Kepler detected nearly 5,000 exoplanets.