Herschel mission overview and key programmes

Herschel is the next astronomy mission in the European Space Agency (ESA) science programme. It is currently in the final stages of assembly and verification in ESA's ESTEC facility in Noordwijk, and is scheduled to be flown to the launch site at Europe's Spaceport in Kourou later this year. Herschel will carry a 3.5 metre diameter passively cooled Cassegrain telescope which is the largest of its kind and utilises novel silicon carbide technology. The science payload comprises three instruments: two direct detection cameras/medium resolution spectrometers, PACS and SPIRE, and a very high resolution heterodyne spectrometer, HIFI. The focal plane units are housed inside a superfluid helium cryostat based on ISO legacy. Herschel will be launched by an Ariane 5 ECA together with the Planck satellite into a transfer trajectory towards the operational orbit around L2. When operational Herschel will provide unprecedented observational opportunities in the 55-672 μm spectral range, much of which has never before been accessible from a space observatory. It is an observatory facility available to the worldwide astronomical community, nominally almost 20,000 hours will be available for astronomy, 32% is guaranteed time and the remainder is open to the general astronomical community through a standard competitive proposal procedure. The initial Key Programme Announcement of Opportunity (AO) was issued in Feb 2007. Both the guaranteed and open time Key Programmes have been selected and are introduced, and future observing opportunities are outlined.