Astronomy is a continuously evolving science. It is the lead research for observation as well as theory. Whereas since antiquity and until the 19th century, the observations were made in the visible domain, the celestial vault is now studied in an always increasing number of electromagnetic spectrum wavelengths: Gamma rays, X rays, Ultraviolet (UV), Visible, Infrared (IR), millimeter and submillimeter domain, radio, ... The multiplication of these observations enables to study increasingly varied phenomena which, at last, improves our global understanding of the Universe.

Different phenomena restrict the on-ground observation possibilities, in which the natural turbulence of the air which creates density variations and thus image instabilities and limits the resolutions to around one arc second. Moreover, some radiations (Gamma, X, ...) are purely and simply absorbed by the atmosphere and thus inobservable from the ground:

Spatial observation plays a fundamendal role in modern astrophysics by enabling measurements unfeasible in the past.

Spatial telescopes working in the visible domain enable to study celestial objects ten times less luminous than those observed from the ground. The ultra-violet (UV) domain is nearly inobservable from the ground due to the atmosphere different constituants opacity (ozone, oxygen, water vapor, ...).

Hot stars emit most of their energy in the UV (often the UV radiation ionizes interstellar clouds, which re-emit IR or visible radiations).
The interstellar environment can be studied in this domain, environment from which stars are formed and in which stellar explosions (supernovae) and matter ejections (novae, eruptive stars) transfer a part of the elements created in stars. This wavelength domain is thus essential to study the stars evolution.

In UV observation domain, CNES funds the Laboratoire d'Astronomie de Marseille (LAM) and the Institut d'Astronomie de Paris (IAP) for their collaboration with NASA to FUSE satellite launched in june 1999 as well as LAM's participation to NASA's GALEX satellite launched in april 2003.

The best instrumental performances in term of angular resolution and photometry are reach in the visible domain, which remains very much used by scientists.

CNES developed COROT in collaboration with several international partners, mission dedicated to 1- the observation of stars vibration modes, characteristic of their internal structure and 2- the detection of small size exoplanets, a few time the terrestrial mass. COROT will be launched at the end of 2006 from Baikonour by a Soyouz rocket.

CNES is also involved, with the French scientific community, in the preparation and analysis of GAIA data, ESA's mission, which launch is scheduled for the end of 2011.

GAIA is an astrometry space mission which will enable to measure the position of a billion objects with an angular precision of 20µas (a hair at 1000km). The catalog will enable to establish a new cartography of our galaxy and will largely improve stellar and galactic physics as well as fundamental physics.

At last, SOHO ESA's mission launched in 1995 dedicated to the study of the Sun, continues its harvest of measurements. France contributed by participating to the realization of 6 experiments which enable to measure the Sun's oscillation modes, including the long period ones which penetrate to the deep layers of the star.

In this domain "cold" celestial objects of the Universe are more easily observable. This naming covers all the objects which temperature is lower than a few hundred Kelvins. They are numerous and can be found at all scales in the Universe, from planets near us to the Universe fossil radiation.

This domain is thus favourable to relatively cold stars observation, either in formation or in end of life. In those two cases, it is the dust clouds that surround them (heated by nearby stars) that emit IR radiations.

Moreover, the sky observation in this domain is particularly useful to study our galaxy (its central part, inobservable in the visible because of the interstellar matter screen, releases a great IR energy), other galaxies (those with a very bright small nucleus emit an enormous IR radiation) as well as our solar system planets' atmosphere.

In this wavelength domain, France is involved at instrument as well as scientific analysis level: CNES supported the development of the acousto-optical spectrometer (AOS) which is on board the ODIN Swedish satellite launched in 2002. The french instrument enables to perform molecular transitions measurements in the millimeter and sub-millimeter domains in order to study physico-chemical processes in the interstellar environment leading to star formation.

ODIN mission also enables to prepare the next ESA mission HERSCHEL, which launch is scheduled for mid-2008. This mission which will observe in the far Infrared will enable to study the galaxies formation and the interstellar environment physico-chemistry. HERSCHEL three instruments, SPIRE, HIFI and PACS, were developed with a large contribution from CNES and scientific laboratories (CEA, LAM, CESR, IAS, ...).

ESA's PLANCK mission is dedicated to the study of the Cosmic Microwave Background. This fossil radiation predicted by the Big Bang theory and observed for the first time in 1964 was emitted about 370 000 years after the big bang when the Universe became transparent while cooling. Due to Doppler shift, it can now be observed in the wavelengths around 2mm. PLANCK's HFI instrument was developed by IAS with CNES support. PLANCK will be launched with HERSCHEL in mid-2008.

At last, a key mission in this observation domain will be NASA's mission JWST intended to replace Hubble telescope by mid 2013. This mission's near and mid-infrared observations (0.6 to 27 µm) will enable to analyse the light emitted by the firsts galaxies. Two out of the three instruments are european, NEARSPEC and MIRI. MIRI (Mid InfraRed Imager) is developed by a european consortium. France (CEA, CNES) develops the MIRIM component which is the instrument's imager.

X rays can appear under high temperature conditions or through interactions between high energy electrons and other particles or magnetic fields. X ray sources can be periodical (pulsars, eclipse binary stars with a component being an X source) or non periodical: radiogalaxies, pulsars, stars, novae, quasars that emit X rays.

These last years, X astronomy knew a revolution with the implementation of X-ray focusing technique. ESA's XMM-Newton mission launched in 1999 uses this technique and has thus enables to reach an angular resolution of 5as between 0.5 and 10 keV. XMM-Newton enabled to individually identify X sources of our galaxy and to show, at the center of the milky way, a black hole several thousands of times the mass of the Sun.

It is known that a black hole should have the property to suck up surrounding matter, particularly nearby stars'. During this attraction, the gas is heated to emit a radiation detectable by XMM-Newton.

The development of sensors able to measure very high energy radiations (typically between a few keV and a few dozen MeV) enabled the detailed observation of violent processes in the Universe (novae, supernovae, active galaxies, etc.) that, until then, were essentially observed in the visible.

This violence results in the existence of a very high energy particles population: the cosmic rays (mixes of protons and nuclei with a low proportion of electrons). From the interaction of these cosmic rays with matter, magnetic fields and light, even some times on their place of apparition, gamma photons are created. They travel in direct line and bring information about their place of birth or about the cosmic rays ones.

The gamma astronomy thus appears as the privilege mean to localize and study sites where high energy transfert associated to particles interaction or nuclear processes happen. The gamma astronomy, by studying violent processes, open the possibility to understand the ultimate phases of stars evolution: pulsars, neutron stars, black holes.

CNES and french laboratories (CEA, CESR) contributed to the instrumentation (SPI and IBIS) of ESA's mission INTEGRAL which studies the Universe and particularly our galaxy in the energy range from 15 keV to 10 MeV.

Among the most outstanding results, INTEGRAL enabled, due to the french instrument SPI, to realize the first complete map of the 511 keV emission (positron/electron annihilation energy). These events mainly happen in the galactic bombing region which cannot be easily explained by current theories. The nature of these antimatter sources will be one of the major interest of the INTEGRAL measurements in the next years. The exploitation of INTEGRAL mission is foreseen until the end of 2010.

In the gamma ray domain, the origin of a phenomenon observed since the 1970, called "Gamma bursts" due to its unpredictable occurrence and its short duration, wonders scientists. CNES and CESR supplied FREGAT instrument to NASA's satellite HETE-2 launched in 2000. This satellite enabled to pierce these short (a few dozen milliseconds) bursts mystery: they are emitted during the formation of black holes by the collision between two neutron stars. It was known since a few years that the longest gamma bursts were created during the absorption of a star by an existing black hole.