Article Posted on : - Apr 30, 2013

The Orion nebula taken by the Herschel and Spitzer space telescopes. Photo: NASA/ESA/JPL-Caltech/IRAM

PASADENA, CALIFORNIA (BNS): The Herschel observatory, a European space telescope for which NASA helped build instruments and process data, has stopped making observations after running out of liquid coolant.

The European Space Agency mission, launched almost four years ago, revealed the universe's "coolest" secrets by observing the frigid side of planet, star and galaxy formation.

NASA said on Monday at the beginning of the spacecraft's daily communication session with its ground station in Western Australia, confirmation was received that helium was exhausted. A clear rise in temperatures was measured in all of Herschel's instruments, it said.

Herschel's detectors were designed to pick up the glow from celestial objects with infrared wavelengths as long as 625 micrometers, which is 1,000 times longer than what we can see with our eyes.

Because heat interferes with these devices, they were chilled to temperatures as low as 2 kelvins (minus 271 degrees Celsius, or 456 Fahrenheit) using liquid helium.

The detectors also were kept cold by the spacecraft's orbit, which is around a stable point called the second Lagrange point about 930,000 miles (1.5 million kilometers) from Earth. This location gave Herschel a better view of the universe.

NASA said the mission will not be making any more observations and the final batch of data will be made public in about six months.

Herschel launched aboard an Ariane 5 rocket from French Guiana in May 2009. NASA's Jet Propulsion Laboratory built components for two of Herschel's three science instruments.