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
Go to topicProtecting life and infrastructure on Earth and in orbit
Go to topicUsing space to benefit citizens and meet future challenges on Earth
Go to topicMaking space accessible and developing the technologies for the future
Go to topicThis artist's view shows the combined focal plane of the two instruments on board ESA's Planck spacecraft. The High Frequency Instrument (HFI) is visible as a circular forest of horns at the centre, surrounded by the Low Frequency Instrument (LFI) ring of horns.
The two instruments detect the collected radiation in different ways. LFI is designed to convert the lower energy microwaves into electrical voltages, rather like a transistor radio. HFI works by converting the higher energy microwaves to heat, which is then measured by a tiny electrical thermometer. The instruments share a common telescope.