The European Space Agency (ESA) is Europe’s gateway to space. Its mission is to shape the development of Europe’s space capability and ensure that investment in space continues to deliver benefits to the citizens of Europe and the world.
Find out more about space activities in our 23 Member States, and understand how ESA works together with their national agencies, institutions and organisations.
Exploring our Solar System and unlocking the secrets of the Universe
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Go to topicMaking space accessible and developing the technologies for the future
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The Low Frequency Instrument (LFI) and High Frequency Instrument (HFI) on Planck will operate at extremely low temperatures; 20 K for LFI and 0.1 K for HFI. To achieve these low temperatures, the satellite employs a three-stage active cryogenic cooler. The last cooling stage makes use of the cooling effect of mixing 4He with the rare isotope 3He at low temperatures (around -272°C).
Both helium isotopes are stored under very high pressure in special tanks and the helium is depleted slowly during the mission. The supply cylinders containing the pressurised helium were inspected and filling activities started on Monday 9 March.