For the first time, a European space probe is to fly to Mars and land on the
planet by the end of 2003. “Mars Express” shall investigate whether there
was once water on our neighboring planet Mars and whether life was formed at
that time. At 150 million euros, this will be the most cost-effective
mission ever undertaken. This has been made possible by the use of proven
technologies and developments of the comet probe “Rosetta” and “Mars 96”.
Furthermore, the European Space Agency ESA has transferred greater
responsibilities to industrial companies. The space company Astrium is the
prime contractor for the construction and development of the “Mars Express”.
New management form allows highly cost-effective Mars mission
At the end of 1998, the European Space Agency ESA added “Mars Express” to
its long-term program “Horizon 2000 Plus”. This was the first project of the
newly formed series of “Flexible Missions”. These are low-cost missions up
to 175 million euros and with short construction times. “Flexible Missions”
was ESA’s response to the NASA strategy ol “cheaper, better, faster”. With
“Mars Express” ESA wanted to compensate the loss of the Russian Mars mission
“Mars 96”, in which European scientists were involved to a large extent. In
November 1996, the launch of “Mars 96” failed and the probe crashed into the
Pacific.
In March 1999, Astrium was awarded a contract for 60 million euros for the
construction and development of “Mars Express”. Since then, development has
been in full swing. “Mars Express”‘ electrical and functional integration
has started in Toulouse. The spacecraft structure has been delivered and the
propulsion system is currently being built.
Compared to previous space missions, the industry has assumed more
management tasks in “Mars Express”. Astrium is, for example, in dined
contact with the scientists entrusted with the instrument design and is
responsible for the interfaces to the probe.
The leading principle of strict adherence to the cost frame by observing the
safety standards, can be achieved by the use of proven technologies. In this
respect, the “Rosetta” mission plays an important role. This comet probe was
also built by Astrium and is to be launched half a year before “Mars
Express”. The hardware and software could be used to a large extent, for
example the attitude and orbit control system. ESA was also able to save
costs since its control center in Darmstadt employs the technology for the
control of “Rosetta” for “Mars Express”. Furthermore, personnel can be
saved on account of the fact that members of ESOC will support both
missions.
Astrium was also able to use developments in commercial telecommunication
satellites. These include the control and propulsion system as well as the
structure of electronic sub-units. Another cost-saving factor has been the
reproduction of scientific instruments which were to fly on “Mars 96”. These
include an infrared camera for the mineralogical analysis of the Martian
surface, two spectrometers for the measurement of water vapor, carbon
dioxide and ozone in the atmosphere and, in particular, the high-resolution
stereo camera (HRSC).
The HRSC is a masterpiece of optics developed and constructed by Astrium as
prime contractor. At that time, Astrium had built a second camera model for
test purposes. After the accident of “Mars 96”, this model was modified for
“Mars Express”. Instead of the originally planned ground resolution of up to
ten meters, it is to detect pram-sized details from a distance of 250
kilometers. This was made possible by the integration of an additional
high-resolution stereo channel developed and built by the German Aerospace
Center (DLR). Four other channels supply color images and two channels are
required for photometric measurements. A special feature is the possibility
to produce stereo images.
With this variety of observation modes, HRSC opens a multitude of prospects
to the planet researchers. It will, for instance, be used for searching
signs of a former ocean or rivers. For example, it is assumed that the
arctic region was previously covered with water. A wide plain is extending
there, whose margins resemble coastal lines. Thanks to its high resolution,
the HRSC is able to provide further information in this respect. Recently,
U.S. researchers have discovered ditches at the slopes of wide canyons.
Water may have emerged from the rocks and flown towards the bottom. In this
case, too, the high-resolution images of the stereo camera may provide more
information.
A radar on board the Mars Express orbiter is also very interesting from a
scientific point of view. It consists of two radar antennas with a length of
20 meters each, which are to scan the Martian surface. The radar waves will
penetrate into the ground to a depth of two to three kilometers and will be
reflected from different strata. Thus, different layers of rock, lava and
sand can be proven. In particular, it will be possible to detect reservoirs
of water ice in the ground. Any evidence of water is valuable because it
helps to reveal the climatic history of our neighboring planet. According to
current knowledge, water is the basic prerequisite for the formation of
life.
The “Beagle” has landed
The “Beagle 2” lander represents a major technical challenge comprising of
the most ambitious science payload to total mass ratio ever attempted.
It was named after the ship “HMS Beagle” in which Charles Darwin sailed
around the world in the early 1830’s. His investigations, in particular on
the Galapagos islands, were the inspiration for his theory of evolution.
Now, “Beagle 2” is to search for signs of life on Mars – a continuation of
man’s quest for answers.
Astrium is responsible for the development and construction of the lander.
The requirements to be met by the probe are demanding: on the one hand, it
shall withstand temperatures up to minus 125 degrees Centigrade – and yet on
the other hand, it must be able to resist violent sand storms with speeds up
to 400 kilometers per hour.
“Beagle 2”, weighing approximately 60 kilograms, will be separated from the
mother ship (Mars Express) and fly towards Mars. A heat shield prevents it
from burning in the upper atmosphere. The parachutes will open at a speed of
1,600 km/h and act as another brake. Finally, airbags will inflate to
attenuate the impact. This method proved successful in the U.S. “Mars
Pathfinder” probe mission.
“Beagle 2” is to land on an even surface which may previously have been the
ground of a large lake or river. After landing, first the lid will open like
a pocket watch, then the solar arrays will unfold and finally – if
everything has worked correctly “Beagle 2” will signal its arrival by
sending a song specifically composed for that purpose by the British pop
group Blur – The exploration of the landing area will now have started.
A camera will produce a 360-degree panorama of the surrounding area and at
the same time, measurement equipment will take recordings of meteorological
values such as wind velocity, temperature and solar radiation.
A novelty “mole” situated at the end of its instrument arm will move across
the Martian surface until it meets rock, at this point it will burrow into
the ground under the rock to a depth of at least one meter. It is here in
this previously “undisturbed” location that Beagle 2 will take samples. The
samples are then carried back to the lander where on board analysis will
search for organic matter.
Additionally, “Beagle 2” will use stereo cameras to detect for
scientifically promising rocks, then using it’s probe will extend an
instrument arm towards these rocks to remove the outer, weathered layer
which is likely to be covered with sand.
Having uncovered the rocks surface “Beagle 2” will use its cameras to take
microscopic pictures in order to gain information regarding the rocks
mineral composition and age.
It will then use its probe, which is equipped with a gas analysis package
and mass spectrometer to determine both the chemical and isotopic
composition of the rocks. The results of which will reveal whether the rocks
are volcanic or sedimentary, the latter being an indication that there was
once water in that area – the most likely of places for life to have existed
or even still exist today.
It is known that the isotope carbon-12 is increased in the metabolism of
earthly living beings. This means they increase the natural relation of
carbon-12 to carbon-13. This characteristic feature has helped researchers
in Greenland to find fossils in rocks which were 3.8 billion years old. A
comparable finding on Mars would be a sensation. Launch with a Soyuz/Fregat
at the beginning of June 2003
A launch window of eleven days will be opened for “Mars Express” on June 1,
2003. During that period, the probe is to be launched on a Russian Soyuz and
the new upper stage Fregat from the Russian Baikonur Cosmodrome. Thanks to
an extremely favorable Mars-Earth constellation, the flight will only take
around six months, resulting in the probe reaching the Red Planet at
Christmas 2003.
The orbiter will then enter an almost polar, highly elliptic orbit. On this
orbit “Mars Express” will approach the surface up to 250 kilometers and
withdraw from it up to 11,500 kilometers. For two Earth years, which
corresponds to one Martian year, the onboard measurement equipment is to
investigate the planet. Within that period the stereo camera is able to map
almost the entire planet. The researcher may thus expect a “rich harvest”.
Astrium, Europe’s leading space company, is a joint venture owned 75% by
EADS and 25% by BAE Systems. With 7,500 employees and an annual turnover of
2 billion Euros, its activities cover science and Earth observation
applications, telecommunications and ground systems, military programmes and
launchers and orbital infrastructure.
Friedrichshafen, June 2001/01010
For further information:
Astrium Earth Observation & Science Mathias Pikelj, Tel.: +49-7545-8-9123
Fax: +49-7545-8-5589 Internet: http://www.astrium-space.com E-mail:
presse-eo@astrium-space.com