Herschel Space Observatory Running On Fumes
March 5, 2013

ESA’s Flagship Space Observatory Is Running On Empty

Lee Rannals for redOrbit.com - Your Universe Online

The European Space Agency said Tuesday that its Herschel Space Observatory is beginning to wrap up its mission. Famous for its ability to view the sky in the entire wavelength range from far-infrared to submillimeter, the space observatory is beginning to run out of its supply of liquid helium coolant. ESA says Herschel is running on its last fumes and will be running empty in the coming weeks.

Herschel first launched on May 14, 2009 with an 11-foot mirror, becoming the world's most powerful infrared telescope ever launched into space. The observatory features three instruments that must be cooled to –455 degrees Fahrenheit. The instruments sit on top of a tank filled with superfluid liquid helium, inside a giant thermos flask known as a cryosat. The helium evaporates over time, gradually emptying the tank and giving the space observatory a proper mission deadline.

Herschel was launched with over 600 gallons (2,300 liters) of liquid helium and weighed 738 pounds, giving it an expected lifespan of 3.5 years. ESA said it is not possible to predict the exact day when the helium will run out, but confirmation will come when Herschel begins its next daily 3-hour communication period with ground stations.

“It is no surprise that this will happen, and when it does we will see the temperatures of all the instruments rise by several degrees within just a few hours,” says Michael Schmidt, the Herschel Mission Operations Manager at ESA´s European Space Operations Centre in Darmstadt, Germany.

The space observatory has helped make some extraordinary discoveries, from starburst galaxies to newly forming planetary systems. ESA engineers have Herschel performing some last-minute observations to try and get the most out of every last drop of liquid helium that still exists on the spacecraft.

“When observing comes to an end, we expect to have performed over 22 000 hours of science observations, 10% more than we had originally planned, so the mission has already exceeded expectations,” says Leo Metcalfe, the Herschel Science Operations and Mission Manager at ESA´s European Space Astronomy Centre in Madrid, Spain.

Göran Pilbratt, ESA´s Herschel Project Scientist at ESA´s European Space Research and Technology Centre in Noordwijk, the Netherlands, said that Herschel data will enable a vast amount of exciting science to be done for many years to come.

“In fact, the peak of scientific productivity is still ahead of us, and the task now is to make the treasure trove of Herschel data as valuable as possible for now and for the future.”

In January, University of Cardiff astronomer Steve Eales wrote in Physics World about how Herschel is already answering some of astronomy's big questions.

“In peering into the big clouds of gas and dust that are the ℠maternity wards´ of stars and then detecting the submillimeter light emitted from the dust around the newly formed stars, Herschel is doing much to study star formation, which is one of astronomy´s ℠big questions´.”

He also wrote about how he was able to find 7,000 new galaxies in a matter of 16 hours using Herschel data. Eales said “the treasure trove of Herschel data will be picked through by astronomers for years to come."