- An infrared observatory will be exploring
for the origin of stars
- Herschel, integrated and tested by Astrium,
is on its way to the European Spaceport in French Guiana
- Astrium has built the largest ever space
telescope, which will be deployed 1.5 million kilometres from the Earth
As part of an international
industrial consortium led by Thales Alenia Space, Astrium Friedrichshafen has
been responsible for building the payload module, which consists of the
cryostat, the optical bench, the scientific instrument harness, the solar array
and sun shade (Astrium subsidiary Dutch Space), and finally the interface
structure to the telescope and the service module (Astrium Spain). Astrium also
integrated the Herschel satellite in Friedrichshafen
and tested it at ESTEC, Astrium Toulouse built the telescope with a light
weight main mirror (3.5-metre-diameter, 350 kg), the largest mirror ever built
for space application, which provided the programme’s primary technical
challenge. By contrast, the Hubble telescope is equipped with a 2.4-metre-diameter
mirror weighing about 1 ton.
The 3.3-tonne Herschel satellite
is currently being transported to the European Space Centre in Kourou, French Guiana. In the next few days, a team of 30 engineers
from Astrium will support the preparation of the infrared observatory for its
launch onboard Ariane 5. Astrium is also the lead company for the Ariane 5
rocket, which will launch the Herschel telescope on April 16, 2009.
The scientists will use the
Herschel space telescope to look billions of light years into space and hence examine
in detail the birth of stars. Herschel will be able to observe the evolution of
stars and galaxies in the infrared range, at resolutions never before achieved.
Herschel will be deployed at the second Lagrangian point (L2), which is around
1.5 million kilometres from Earth.
Herschel will be able to
detect even the slightest heat radiating from cosmic dust when it starts
condensing to form stars and galaxies. To avoid sensitive instruments being
“blinded” by the heat generated by themselves, they have to be cooled to minus
271,5 degrees Celsius, which is less than 2 degrees above absolute zero. The
low temperature is attained by 2,300 litres of superfluid helium inside the
cryostat being sufficient for more than 4 years of operating in space.
Looking deep into space for a better understanding of
the stars
Astronomers can see an
entirely different universe in the infrared spectral range than in visible
light. The advantage of infrared beams is that they
can also penetrate dust clouds and therefore allow scientists critical insights
into the birth processes of stars and their planetary systems. A young star
begins radiating visible light when it is sufficiently compressed by gravity to
set off nuclear fusion processes deep inside it. Just before the fusion begins,
the so-called protostar is still very cold and only gives off heat at a few
degrees Kelvin. Researchers are especially curious about this radiance, as it
provides information on a star's early development stage.
Another goal of the researchers is to analyze young galaxies
that are located billions of light years away from us. They were created a
short time after the Big Bang and generated up to one hundred times more stars
than is the case in galaxies today. Because the universe is expanding, the
light from these “teenage” galaxies is shifted to longer wavelengths, an event
referred to by astronomers as a spectral red shift. The radiation from these
young galaxies, billions of light years away, is therefore predominantly in the
infrared part of the spectrum – and this is precisely the range in which the
Herschel sensors work.
Using high-resolution spectroscopy, Herschel will also
examine the composition of the surfaces and atmospheres of planets.
The space
telescope was named after Friedrich Wilhelm Herschel (1738-1822), who
discovered the planet Uranus and who also identified infrared radiation in 1800,
and his sister Caroline Herschel (1750 – 1848), who discovered 8 comets and 3
nebulae.
Astrium, a
wholly owned subsidiary of EADS, is dedicated to providing civil and defence
space systems and services. In 2007, Astrium had a turnover of €3.5 billion and
12,000 employees in France, Germany, the United
Kingdom, Spain
and the Netherlands.
Its three main areas of activity are Astrium Space Transportation for launchers
and orbital infrastructure, Astrium Satellites for spacecraft and ground
segment and its wholly owned subsidiary Astrium Services for the development
and delivery of satellite services.
EADS
is a global leader in aerospace, defence and related services. In 2007,
EADS generated revenues of €39.1 billion and employed a workforce of more
than 116, 000.
Press contacts:
Jeremy Close
(Astrium UK) Tel.:
+44 (0)1 438 77 3872
Matthieu Duvelleroy (Astrium FR) Tel.:
+33 (0) 1 77 75 80 32
Mathias
Pikelj (Astrium GER) Tel.:
+49 (0) 7545 8 9123
Francisco Lechón (Astrium SP) Tel.:
+34 91 586 37 41
www.astrium.eads.net
