The Herschel Space Observatory ais scheduled for launch with the Planck Surveyor on February 15, 2007 by an Ariane 5ESV. The spacecraft will separate after launch and proceed to different orbits around L2, located 1.5 million km away from Earth.

The 3250 kg (7163 lbm) Herschel Space Observatory, formerly called FIRST (Far Infrared and Sub-millimeter Telescope), is an ESA Cornerstone mission. Herschel is a large imaging space telescope, with a primary mirror 3.5 m in diameter. It will study how the first stars and galaxies formed in the early Universe, more than 12 billion years ago. It is designed to provide imaging spectroscopy and photometry in the spectral range of 80-670 mm. It will be the first space observatory covering the full far-infrared and sub-millimeter waveband. Astrium GmbH will be responsible for the Herschel Payload Module development, as well as with the Herschel spacecraft assembly and testing. Herschel, is named after the British astronomer William Herschel, who discovered infrared light 200 years ago. The cryogen supply limits the planned lifetime of the spacecraft to 4.5 years.

Herschel is an observatory-class mission. One-third of the total observing time, Guaranteed Time, is reserved for the instrument and mission teams. The remaining two-thirds of the total observing time, Open Time, will be available to the astronomical community at large by the conventional procedure of proposal submission and peer review.

Alenia Spazio will be responsible for the Service Modules for the Herschel spacecraft - where telecommunications and 'spacecraft housekeeping' components are located.