Herschel to be refilled with Helium

Please notice that this story was issued on 1 April 2011, which is April Fools' Day.

The Herschel Project Scientist has announced the results of a recent study carried out by industrial partners. The study has confirmed that it is technically feasible and affordable to refill Herschel's cryostat with helium, allowing the mission to be extended. To avoid excessive warming up of the cryostat, the re-fill must take place in autumn 2012. The existing plan for the refill, which is subject to final confirmation, is that Herschel will be returned to low-earth orbit and docked with the International Space Station. The top-up of the helium will be carried out by astronauts on the orbiting space station, after which Herschel will be returned to its current position at L2.

The cryostat contained around 2200 litres of liquid helium at launch, which keeps the instruments within a few degrees of absolute zero (-273 Celsius). During this process, the helium boils off, and is currently expected to run out some time around late 2012. This is what has limited the mission lifetime until this point.

Prof Matt Griffin, of Cardiff University, and lead scientist of the SPIRE instrument, said "I've always thought it was a shame that we only had a few years to use Herschel, so the fact that this has been extended is excellent news. Now we have the wonderful task of deciding what to do with this ground-breaking observatory for the second phase of the mission".

The cost of the operation is due to the late-running of some other projects, which has freed up funds. Industrial partners are currently finalising the detailed plan of the Herschel refilling mission, with International Space Station astronauts to begin training for it later this year. An artist's impression of Herschel docked to the space station is shown below.

Artoist's impression of Herschel docked to the International Space Station
Artist's impression of Herschel docked to the International Space Station. Click for larger image.

Sadly, Herschel does not carry enough fuel to travel to low-Earth orbit and return to L2, and is incapable of docking to the International Space Station.