NASA says its Kepler telescope has woken up again after being put in sleep mode – although the future of the mission still looks short-lived.
In an update posted yesterday, the agency said the telescope had begun a new observation campaign on August 29, its 19th overall, to hunt for planets beyond the Solar System. This was after it had been placed in hibernation due to a lack of fuel.
“After being roused from sleep mode the spacecraft's configuration has been modified due to unusual behavior exhibited by one of the thrusters,” NASA said in the update.
“Preliminary indications are that the telescope's pointing performance may be somewhat degraded. It remains unclear how much fuel remains; NASA continues to monitor the health and performance of the spacecraft.”
The telescope was placed in sleep mode on August 24, following the news earlier this year that the spacecraft was running out of fuel. While there isn’t a fuel meter per se on board, scientists can monitor the pressure of the fuel tank to see how it’s doing.
Kepler needs fuel in order to point itself at stars and find planets. It does this by watching for a dip in light as planets pass in front of the stars, known as the transit method, which has proven wildly successful. But it looks like its fuel will run out by the end of 2019.
To date Kepler has found more than 2,500 confirmed planets, with another 2,700 or so awaiting confirmation. The telescope is in its second mission, called K2, after it lost the use of one of its reaction wheels used to point at stars in 2013.
When the mission does come to an end, it will be an incredibly sad time for exoplanet scientists. Kepler has redefined what we knew about planets beyond our Solar System, forever changing how we view our place in the galaxy.
Its successor, the Transiting Exoplanet Survey Satellite (TESS), was launched earlier this year and began science operations in July. But Kepler’s not done yet – it’ll keep searching for planets on this latest observation campaign until its fuel runs out, whenever that may be.