This has been achieved with the aid of a cooling system run on superfluid helium, more than 2, 000 litres of which were loaded into the telescope at launch.

BBC: Herschel space telescope to go blind

Hydrocarbons, helium, hydrogen, and volatiles in the solar system are important for human exploration and habitation because they will provide essential high-energy, high-density fuels and feedstock for off-world manufactured goods and materials for construction.

FORBES: Move up http://i.forbesimg.com t Move down

This approach is described as a "passive" system because once initial conditions are set inside the flask, a continuing presence of helium and good insulation is all that is required to maintain those conditions.

BBC: Herschel space telescope finishes mission