Photo: Herschel
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Today´s Ariane 5 Launch from Kourou marks the 30th successful launch in a row
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Astrium builds the world’s largest space telescope
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Instruments can detect the faintest radiation in the universe due to super-cooling
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Astrium also delivers key components for the Planck research satellite
A picture-perfect launch from the Kourou Space Centre in French Guyana: Today, at 3:12 p.m. CEST, the scientific satellites Herschel and Planck were launched aboard an Ariane 5 rocket. Herschel, the largest mirror telescope ever put into space, will detect the invisible infrared light of distant galaxies and observe the birth of stars and planets. The Planck satellite will peer into the outer reaches of space and examines the cosmic background radiation. Both missions are milestones of modern astronomy and Europe’s major contribution to the Year of Astronomy 2009. The space company Astrium is actively involved in both of these European Space Agency (ESA) projects.
The two satellites are being launched towards the Lagrange Point L-2 once again demonstrating the operational capabilities of Ariane 5. This is the only launch vehicle on the commercial market today capable of launching two payloads simultaneously, and handling a complete array of missions, from commercial launches into geostationary orbit, to scientific missions into special orbits. It is the 30th successful Ariane flight in a row. Astrium is the prime contractor for this launch vehicle.
About 26 minutes (Herschel) and 28 minutes (Planck) after the lift-off in Kourou, the satellites separated from Ariane’s upper stage; about 12 minutes later, the ground stations received first signals of both telescopes. In about six months, Herschel and Planck will reach their operational orbits at the second Lagrange point L-2 and start their scientific work. The L-2 Lagrangian point of the Sun-Earth system is a gravitational stability point suspended in space some 1.5 million kilometres from Earth in the opposite direction to the Sun. While orbiting around that point, the spacecrafts will be able to conduct continuous observations in a thermally-stable environment, far from radiation disturbance caused by the Sun, Earth and Moon. On their way to their destinations, the Herschel subsystems and instruments will be commissioned and their functions will be checked.
Herschel – Super-cool telescope studying the formation of stars
As part of an international industrial consortium led by Thales Alenia Space, the Astrium site in Friedrichshafen is responsible for Herschel’s payload module consisting of a cryostat (a “super-cooling” system), the optical unit with the instruments and the solar arrays with a sun protection shield (Astrium’s subsidiary Dutch Space). Astrium Spain is involved in the Herschel payload module with electronic parts for the PACS instrument as well as with the electrical cryo-harnesses with extremely low heat conductivity, the service module carbon-fibre structure and the mounting struts to the payload module. In addition, Astrium (Friedrichshafen) is responsible for satellite integration and testing. One of the main technical challenges in implementing Herschel was the lightweight mirror built by the Astrium site in Toulouse and the company Boostec.
This mirror has a weight of only 350 kilograms and a diameter of 3.5 metres. At present, Herschel is the largest imaging space telescope in space. By comparison, the mirror of the Hubble telescope – which operates in the visible wavelength range – is only 2.4 metres across and weighs about one metric ton.
Scientists intend to use the Herschel telescope to peer billions of light years back into deep space and to examine the birth and early development of the stars. Herschel is to observe forming stars and galaxies in the infrared with an unprecedented resolution. Herschel will be able to detect even the weakest heat radiation emanating from cosmic dust as it begins to develop into stars and galaxies. The sensitive instruments need to be cooled to minus 271.5 degrees Celsius (less than two degrees above the absolute zero) inside the cryostat to prevent them from being “blinded” by the heat radiation produced during the satellite’s operation. This low temperature will be achieved using 2,300 litres of liquid helium, which is enough to keep the satellite going in space for more than four years.
Planck – Tracking down the light of the Big Bang
ESA’s Planck research satellite will help scientists “travel back in time†13.8 billion years to the beginnings of the universe and detect its “first lightâ€. The satellite’s two telescope mirrors developed by Astrium in Friedrichshafen have a carbon-fibre sandwich design and will play a key role in capturing what is known as cosmic radiation. They will focus the incident microwave radiation onto two highly sensitive instruments. Astrium Spain provided the structure of the service module and the electronic components for the Planck cooling as well as the instruments HFI and LFI.
Cosmic background radiation is a relic from the dawn of our universe. It began to form just a few hundred thousand years after the Big Bang, when the temperature of the universe was still several thousand degrees. During this period, free protons and electrons – which diverted the direction of the radiation – joined to form neutral hydrogen atoms, and the universe became transparent.
The Planck space telescope will measure this radiation in nine different wave bands over a period of up to two-and-a-half years from its position near the second Lagrange point using a high-frequency and a low-frequency instrument.
By detecting the faintest temperature differences, Planck will not only be able to examine the early stages of our universe, but will hopefully also provide answers to vital cosmological questions: What exactly happened during the Big Bang? What types of matter, radiation and energy is the universe made of today? How old is it, and how did its structures form?
Source: EADS / ESA
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