Engineers at the Japan Aerospace Exploration Agency (JAXA) are still hoping they can keep the partially crippled Akari infrared astronomy satellite running despite a major electrical failure that renders the satellite’s science instruments inoperable when the satellite is in the Earth’s shadow.

Akari switched itself into power-saving mode May 24, turning off its on-board observation devices, according to the agency. A preliminary investigation submitted the next day to Japan’s Space Activities Commission found that while the satellite’s solar arrays are still generating electricity, the satellite is unable to store electricity due to either a problem with the satellites batteries or electrical system, JAXA spokesman Eijiro Namura said May 27.

“The solar panels are working fine, but the batteries are not charging for some reason we are still trying to figure out,” he said.

The 952-kilogram Akari satellite, also known as Astro-F, was launched in 2006 on an M-5 rocket on a nominally three-year mission to survey the entire sky in near-, mid- and far-infrared.

Akari’s 750-kilometer sun-synchronous polar orbit takes it around the Earth once every 100 minutes, which means the satellite spends only 20 minutes of each orbit in the Earth’s shadow. Because engineers can communicate with the satellite and collect data when Akari is out of the Earth’s shadow, JAXA is reluctant to declare the mission over and is still looking to see if it can restore the satellite’s observation functions, Namura said.

“Akari has been operating well beyond its designed mission life, but we can still collect and analyze data while the satellite is not in the shade,” Namura said.