The "Herschel Space Observatory" (formerly known as the "Far
InfraRed and Submillimetre Telescope" - FIRST) is the
fourth cornerstone mission in the European Space Agency (ESA)
science programme. It will perform imaging photometry and
spectroscopy in the far infrared and submillimetre part of the
spectrum, covering approximately the 57-670 μm range. The key science objectives emphasize current questions connected
to the formation of galaxies and stars, however, having unique
capabilities in several ways,
Herschel will be a facility available to the entire astronomical
community. Because Herschel to some extent will be its
own pathfinder, the issue of instrument calibration and data
processing timescales has special importance. Herschel will carry a 3.5 metre diameter passively cooled telescope.
The science payload complement - two cameras/medium resolution
spectrometers (PACS and SPIRE) and a very high resolution heterodyne
spectrometer (HIFI) - will be housed in a superfluid helium
cryostat. Herschel will be placed in a transfer trajectory towards
its operational orbit around the Earth-Sun L2 point
by an Ariane 5 (shared with the ESA cosmic background mapping
mission Planck) in early 2007. Once operational Herschel will offer a
minimum of 3 years of routine observations; roughly
2/3 of the available observing time is open to the general
astronomical community through a competitive proposal
procedure.