Photo by the European Space Agency
Read Caption
Shortly after its 2009 launch, the Herschel Space Observatory traveled to its survey location 1.5 million kilometers from Earth.
Photo by the European Space Agency

Herschel Space Observatory Running On Empty

After three years of scouring the universe for evidence of the most distant galaxies, the Herschel Space Observatory is running out of fuel.

The European Space Agency launched the craft in 2009 with some of the most advanced light-sensing equipment ever developed. Only when it got above Earth’s clouds would Herschel be able to peer into deep space, up to 10 billion light years away.

The module was named after William Heschel, who discovered Uranus back in 1781, in hopes that new technology to see past interference like dust, asteroids and clouds, might yield some clues about the far reaches of the universe.

Over those three years, Herschel has radioed back some astounding data. From millions of miles away, it could spot molecular oxygen in the Orion star cluster . Several months later, it helped crystallize scientists’ long-held views that Earth’s water likely came from comets.

Unlike the Voyager spacecraft, which have spent their lives traveling away from Earth, Herschel sat still, held in place between the Earth and Sun’s gravity about 1.6 million kilometers (990,000 miles) away. It launched with 2,160 liters (570 gallons) of liquid helium to cool its on-board computers, which run mostly on solar power. Now, European scientists expect the helium tank to run dry in March, causing the equipment to overheat and skew infrared data coming in.

At the end of it’s useful life, Herschel’s story isn’t such bad news. Steve Eales, an astronomer at the University of Cardiff in Wales, has spent months following Herschel’s data, once turning up evidence of 7,000 new galaxies in just 16 hours. Even when Heschel’s fuel tank runs dry, Eales and his colleagues likely have enough data to keep making new discoveries about the universe long into the future.

Correction: An earlier version of this story said the University of Cardiff was in England. It is, in fact, in Wales. We regret the error.