Herschel Space Observatory Nears End Of Epic Mission
By Ed Pierce // May 10, 2013
Supply Of Liquid Helium Running Out
ABOVE VIDEO: As the largest and most powerful infrared telescope ever flown in space, the Herschel observatory is a European Space Agency mission with important participation from NASA that was launched in 2009.
BREVARD COUNTY • KENNEDY SPACE CENTER, FLORIDA – After more than three years studying the universe and surpassing all expectations of scientists and astronomers, the Herschel Space Observatory will soon exhaust its supply of liquid helium coolant in the coming days.
As the largest and most powerful infrared telescope ever flown in space, the Herschel Observatory is a European Space Agency mission with important participation from NASA that was launched in 2009.
It has a main mirror some 11.5 feet across and has been the first infrared telescope to cover the entire wavelength range making it possible to study previously invisible cool regions of gas and dust in the universe and offer insight into the origin and evolution of stars and galaxies.
In order to make such measurements, scientific instruments aboard Herschel require cooling to minus 456 degrees Fahrenheit or close to absolute zero on top of a tank filled with liquid helium, inside a giant thermos flask known as a cryostat.
This helium evaporates, gradually emptying the tank. When launched, the cryostat was filled with more than 606 gallons of liquid helium, weighing 739 pounds for about 3.5 years of service.
Engineers say almost all of the liquid helium is now evaporated, bringing the mission to a close
“We have known from the beginning of the mission that Herschel’s lifetime would be limited by the supply of liquid helium.” said Paul Goldsmith, the NASA Herschel Project Scientist at NASA’s Jet Propulsion Laboratory in a press release. “So the whole team worked very hard to make the best use of every minute of observing time.”
Before its time is exhausted, Herschel is performing numerous other observations.
“When observing comes to an end, we expect to have performed over 22,000 hours of science observations, 10 percent more than we had originally planned, so the mission has already exceeded expectations,” said Leo Metcalfe, the Herschel Science Operations and Mission Manager at ESA’s European Space Astronomy Centre in Spain.
He said data obtained from Herschel will continue to be studied for some time in the future.
The Herschel mission has been monumental, taking a giant step forward in infrared technology while bridging the gap between the wavelengths seen by previous infrared satellites and those observed by radio telescopes on ground.
The exact day and time the helium will run out is not certain, but NASA says Herschel will continue to communicate with its ground stations on Earth for a number of weeks after the helium is used up and will perform a variety of technical tests.
Early this month, the spacecraft will be maneuvered into a stable long-term orbit revolving around the sun.