Size hi-res: 4522 kb

Credits: ESA (Image by AOES Medialab); background: Hubble Space Telescope, NASA/ ESA/ STScI

Herschel will have an unprecedented view of the cold universe, bridging the gap in the spectrum between what can be observed from ground and earlier space missions of this kind. Infrared radiation can penetrate the gas and dust clouds that hide objects from optical telescopes, looking deep into star-forming regions, galactic centres and planetary systems. Cooler objects, such as tiny stars and molecular clouds, even galaxies enshrouded in dust, barely emitting optical light, are visible in the infrared. Observing in the infrared provides us with a complementary view of the universe.

Size hi-res: 3111 kb

Credits: ESA (Image by AOES Medialab)

Herschel will carry the largest space telescope ever launched to date. From a point in space called the 2nd Lagrangian Point (or L2), its 3.5-m diameter mirror will collect long-wavelength infrared radiation from some of the coolest and most distant objects in the Universe. Herschel will be the only space observatory to cover the range from far-infrared to sub-millimetre wavelengths. The mission is to be launched in July 2008, in tandem with ESA's Planck spacecraft, by an Ariane-5 rocket from Europe's Spaceport in Kourou (French Guiana).

Size hi-res: 3544 kb

Credits: ESA (Image by AOES Medialab)

This picture shows an artist's impression of the view inside Herschel.

To protect the sensitive instruments from heat generated during operations and to achieve its challenging objectives, the satellite must operate at very low temperatures. This is why the spacecraft’s brain – or its payload module – hosts a cryostat, a cryogenic module inside which the cold components of the scientific instruments are mounted.

Inside the cryostat the sensitive instrument detectors are cooled down to about -273 ºC (0.3 degrees above absolute zero). This low temperature is achieved using superfluid helium (at about -271 ºC) and an additional cooling stage inside the focal plane units.

The service module is the spacecraft’s heart, which keeps the spacecraft going by caring for all its vital functions. It also carries the ‘warm’ components of the instruments – those that do not require cooling with the cryostat.

Size hi-res: 1321 kb

Credits: ESA

The gigantic telescope of ESA’s Herschel infrared space observatory as it was being prepared for assembly with its spacecraft. Herschel uses the largest mirror ever flown in space.

Size hi-res: 1283 kb

Credits: ESA - Guarniero

Herschel will launch on an Ariane-5 rocket from the Guyana Space Centre, Kourou, French Guyana, in July 2008. It will be part of a shared launch, along with ESA's Planck spacecraft. The two vehicles will separate shortly after launch and proceed independently to different orbits around the second Lagrange point of the Sun-Earth system (L2). The Ariane-5 will burn its solid boosters for slightly less than 2.5 minutes and its main and upper stage engines for about 25 minutes to inject Herschel and then Planck into transfer trajectories bound for L2.

Size hi-res: 1981 kb

Credits: ESA (Image by AOES Medialab)

This is an artist's impression of Herschel’s superfluid helium tank.

To protect the sensitive instruments from heat generated during operations and to achieve its challenging objectives, the satellite must operate at very low temperatures. This is why the spacecraft’s brain – or its payload module – hosts a cryostat, a cryogenic module inside which the cold components of the scientific instruments are mounted.

Inside the cryostat, the sensitive instrument detectors are cooled down to about -273ºC (0.3 degrees above absolute zero). This low temperature is achieved using superfluid helium (at about -271ºC) and an additional cooling stage inside the focal plane units.

Inside the tank, helium is kept in its superfluid state at its boiling point (1.65 K or –271.5°C). The helium liquid and gas cools the focal plane units of the instruments and the shields. The liquid boils and a porous plug allows the separation of the liquid from the gas such that only gas leaves the tank. It slowly flows from the tank into pipes around the payload to cool it to between 1.7 K (–271.4°C), 4 K (–269°C) and about 10 K (-263°C).

The gas then continues into the rings of three thermal shields to cool them to 30K (–241°C), 50 K (–221°C) and 60 K (–211°C), respectively.

The gas is then finally released in space. The cryostat vacuum vessel is facing cold space and radiatively cools to about 70 K (–203°C).

Size hi-res: 1902 kb

Credits: ESA

Three on-board instruments turn Herschel’s telescope from a mere light collector into a pair of hi-tech eyes. The instrument detectors form the retina, where the light from astronomical objects is really seen. The instruments then detect and analyse the light in many different ways.

This artist’s impression shows the top view of the Herschel focal plane, with the focal plane units (FPUs) of the three scientific instruments: HIFI (Heterodyne Instrument for the Far Infrared), a high-resolution spectrometer, developed under the coordination of the SRON Netherlands Institute for Space Research; PACS (Photoconductor Array Camera and Spectrometer), developed under the coordination of the MPE, Germany; SPIRE (Spectral and Photometric Imaging REceiver), a camera, developed under the coordination of the Cardiff University (UK).

The three focal plane units are mounted on top of the optical bench inside the cryostat vacuum vessel, the top of which has been removed in this view to reveal the focal plane.