Press release

After 10 months of testing, with 65 days under vacuum in cryogenic conditions, the Planck satellite will leave Liège Space Centre (CSL, University of Liège) by cargo plane from Liège Airport for the Kourou base, where it will be launched with an Ariane 5 next April, together with the Herschel satellite.

The Planck mission is a cornerstone of the European Space Agency’s science programme (ESA). Its mission is to map the cosmic microwave background radiation: this radiation will allow to find traces of the universe’s first moments, shortly after the Big Bang. The measurements with an accuracy never achieved until now, will improve our knowledge on the age, composition and the first phases of our universe’s life. The satellite was designed and built by the company Thales Alenia Space for the ESA.


Following a long 7-year preparatory phase, the ESA entrusted the final satellite verifications to CSL (University of Liège). The challenge faced by CSL was to reproduce, in a vacuum, the extreme temperature and pressure conditions that the satellite will undergo once in its final orbit, at 1.5 million km away from Earth. At this distance, equivalent to three times the distance between the Earth and the moon in the opposite direction to the sun, the core of the satellite will be cooled to a temperature close to absolute zero, between -253°C and -273°C.

CSL, which is one of the four ESA coordinated test facilities, therefore developed complex cooling systems to cool a 1.8 ton satellite down to -220°C. The coldest point of the satellite reached -273,05°C (0.1°C from absolute zero), a temperature maintained for two weeks, which represents a very high level technical challenge. Indeed, it is the only time that the Planck satellite’s complete cooling chain was tested on Earth before its launch.

For CSL, the series of tests required a permanent daily monitoring on site to maintain the tests as well as the preparations performed by Thales Alenia Space, the ESA engineers and the teams of scientists. The work was carried out 7 days a week, 24 hours a day. In total, the campaign represented 20,000 working hours in 2008 for CSL.

About the Planck satellite

The Planck satellite (based on the name of the German physicist Max Planck) will allow fundamental discoveries to be made on the very first phases of the universe thanks to its very finely-tuned equipment, high-performance spatial resolution and a wide frequency coverage.

It will be launched in April from the Kourou base in French Guyana (CSG). It will reach its orbit, at 1.5 km from the Earth, at the end of a five-month journey. Its observations will last 18 months.

Planck is composed of

• A telescope 1.5 m in diameter, fitted with a primary and secondary mirror
  
  
• Two instruments, the “eyes of the satellite”:
  
  
  • LFI (Low Frequency Instrument), including a detector covering the low frequencies (30 GHz-77GHz), will make observations in the domain of microwaves
    
    
  • HFI (High Frequency Instrument), equipped with 36 bolometric detectors covering the high frequencies and measuring energy in the infrared and microwave spectrum (100 GHz-857 GHz).
    

Planck will be sensitive to temperature variations of some millionths of a degree and will map the whole sky in nine wavelengths.

www.esa.int/esaSC/120398_index_0_m.html

About the Centre Spatial de Liège  (CSL)

The Centre Spatial de Liège (CSL) is a research centre at the University of Liège (Belgium). It currently employs 83 people. It is an internationally renowned centre of excellence in optics. It is specialised in the evaluation of optical payloads (mirrors, cameras, detectors, etc.) to be embarked on board satellites. CSL is equipped with space simulators of varying dimensions, located in clean areas in order to carry out tests that reproduce the conditions in space. CSL is also active in the development of scientific instruments and in several domains of new technologies, in relation with the Walloon SKYWIN and MECATECH competitiveness clusters.

CSL is one of the four coordinated test facilities to serve the European Space Agency (ESA). It also works with NASA, industries as well as with high level European and American laboratories.

It has actively participated in several important space exploration projects: the GIOTTO probe, HUBBLE Space Telescope, SOHO, NEWTON, INTEGRAL, COROT, STEREO, HERSCHEL satellites.

After the Planck satellite, CSL will participate to the tests of the GAIA payload, the next major ESA science mission.

www.csl.ulg.ac.be