The European Space Agency's Planck satellite, launched on 14 May 2009, is the third-generation space experiment in the field of cosmic microwave background (CMB) research. It will image the anisotropies of the CMB over the whole sky, with unprecedented sensitivity ( ΔT T ∼ 2 × 10 −6 ) and angular resolution (∼5 arcmin). Planck will provide a major source of information relevant to many fundamental cosmological problems and will test current theories of the early evolution of the Universe and the origin of structure. It will also address a wide range of areas of astrophysical research related to the Milky Way as well as external galaxies and clusters of galaxies. The ability of Planck to measure polarization across a wide frequency range (30−350 GHz), with high precision and accuracy, and over the whole sky, will provide unique insight, not only into specific cosmological questions, but also into the properties of the interstellar medium. This paper is part of a series which describes the technical capabilities of the Planck scientific payload. It is based on the knowledge gathered during the on-ground calibration campaigns of the major subsystems, principally its telescope and its two scientific instruments, and of tests at fully integrated satellite level. It represents the best estimate before launch of the technical performance that the satellite and its payload will achieve in flight. In this paper, we summarise the main elements of the payload performance, which is described in detail in the accompanying papers. In addition, we describe the satellite performance elements which are most relevant for science, and provide an overview of the plans for scientific operations and data analysis.

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Herschel cryogenics instrument (HIFI, PACS, SPIRE) flight models have been delivered to ESA & Prime contractor Thales Alenia Space mid 2007, to be integrated and tested on the Herschel spacecraft, for a launch mid May 2009.The instrument integration and test campaign at spacecraft level was performed between mid 2007 and end 2008 in Astrium GmbH, Immenstadt (Gernany) and later in ESA's test facilities at Estec, Noordwijk (Nederland). The objective of these tests was to demonstrate full operability and performances of the instruments in spacecraft configuration, and their compatibility with the launch and space environment, while maintaining full compliance with the underlying requirements. A set of short functional tests were developed and used repeatedly to quickly check the health of each instrument at key points in the test campaign. Typically, this was after integration of a major component, prior to a major environmental test or before/after movement of the spacecraft. A set of full 1510 CREDIT LINE (BELOW) TO BE INSERTED ON THE FIRST PAGE OF EACHPAPER EXCEPT FOR ARTICLES ON pp. 18-25, 26-33, 68-75, 121-127, 136-142, 207-214, 246-253, 355-362, 388-395, 499-506, 507-514, 609-614, 780-787, 796-803, 804-811, 905-912, 1291-1300, 1301-1308, 1369-1376, 1581-1592, 1593-1600, and 1647-1651 functional tests were also performed after launch vibration tests, and during Thermal vacuum test in order to provide a more complete picture of the instruments functional health. Finally a set of instrument specific tests were performed to verify the performance of the instrument under the most representative operational conditions possible on ground (i.e. the environmental test campaign). The paper will describe instruments and the instruments related tests performed at spacecraft level, focusing on cryogenics aspects.

Since its launch on May 14th 2009 Herschel is the largest telescope of its kind in space. Herschel's 3.5-metre diameter mirror collects long-wavelength infrared radiation from some of the coldest and most distant objects in the Universe. Herschel is the only space observatory to cover the spectral range from far-infrared to sub-millimetre wavelengths. The Herschel satellite is 7.5 metres high and 4 metres wide, with a launch mass of approximately 3.3 tonnes. The bulk of the spacecraft consists of a superfluid liquid helium cryostat inside which three scientific instruments (PACS, SPIRE & HIFI) are operated. Via various cooling stages the instruments are cooled to between a few tens and a few tenths of a degree above absolute zero. This paper gives a brief overview of the spacecraft and the on-ground testing, with an emphasis on the cryogenic issues encountered.