ESA News
http://www.esa.int

3 April 2006

Asteroids: treasures of the past and a threat to the future

If a large asteroid such as the recently identified 2004 VD17 -- about
500 m in diameter with a mass of nearly 1000 million tonnes -- collides
with the Earth it could spell disaster for much of our planet. As part
of ESA's Near-Earth Object deflecting mission Don Quijote, three teams
of European industries are now carrying out studies on how to prevent this.

ESA has been addressing the problem of how to prevent large Near-Earth
Objects (NEOs) from colliding with the Earth for some time. In 1996 the
Council of Europe called for the Agency to take action as part of a
"long-term global strategy for remedies against possible impacts".
Recommendations from other international organisations, including the UN
and the Organisation for Economic Cooperation and Development (OECD),
soon followed.

In response to these and other calls, ESA commissioned a number of
threat evaluation and mission studies through its General Studies
Programme (GSP). In July 2004 the preliminary phase was completed when a
panel of experts appointed by ESA recommended giving the Don Quijote
asteroid-deflecting mission concept maximum priority for implementation.

Now it is time for industry to put forward their best design solutions
for the mission. Following an invitation to tender and the subsequent
evaluation process, three industrial teams have been awarded a contract
to carry out the mission phase-A studies:

* a team with Alcatel Alenia Space as prime contractor includes
subcontractors and consultants from across Europe and Canada; Alcatel
Alenia Space developed the Huygens Titan probe and is currently working
on the ExoMars mission

* a consortium led by EADS Astrium, which includes Deimos Space from
Spain and consultants from several European countries, brings their
experience of working on the design of many successful ESA
interplanetary missions such as Rosetta, Mars and Venus Express

* a team led by QinetiQ (UK), which includes companies and partners in
Sweden and Belgium, draws on their expertise in mini and micro
satellites including ESA's SMART-1 and Proba projects

This month the three teams began work and a critical milestone will take
place in October when the studies will be reviewed by ESA with the
support of an international panel of experts. The results of this phase
will be available next year.

No reason for panic -- yet

The risk is still small however, and may decrease even further when new
observations are carried out. Still, if this or any other similar-sized
object, such as 99942 Apophis, an asteroid that will come close enough
to the Earth in 2029 to be visible to the naked eye, collided with our
planet the energy released could be equivalent to a significant fraction
of the world's nuclear arsenal, resulting in devastation across national
borders.

Luckily, impacts with very large asteroids are uncommon, although
impacts with smaller asteroids are less unlikely and remote in time. In
1908 an asteroid that exploded over Siberia devastated an unpopulated
forest area of more than 2000 km2; had it arrived just a few hours
later, Saint Petersburg or London could have been hit instead.

Fossils of the Solar System

Asteroids are a part of our planet's history. As anyone visiting the
Barringer Meteor Crater in Arizona, USA or aiming a small telescope at
the Moon can tell, there is plenty of evidence that the Earth and its
cosmic neighbourhood passed through a period of heavy asteroid
bombardment. On the Earth alone the remains of more than 160 impacts
have been identified, some as notorious as the Chicxulub crater located
in Mexico's Yucatan peninsula, believed to be a trace of the asteroid
that caused the extinction of the dinosaurs 65 million years ago.

Collisions have shaped the history of our Solar System. Because
asteroids and comets are remnants of the turbulent period in which the
planets were formed, they are in fact similar to 'time capsules' and
carry a pristine record of those early days. By studying these objects
it is possible to learn more about the evolution of our Solar System as
well as 'hints' about the origins of life on Earth.

Comet 67P/Churyumov-Gerasimenko is one of these primitive building
blocks and will be visited by ESA's Rosetta spacecraft in 2014, as a
part of a very ambitious mission -- the first ever to land on a comet.
Rosetta will also visit two main belt asteroids (Steins and Lutetia) on
its way to comet 67P/Churyumov-Gerasimenko. The mission will help us to
understand if life on Earth began with the help of materials such as
water and organisms brought to our planet by 'comet seeding'.

ESA's Science programme is already looking at future challenges, and its
Cosmic Vision 2015-2025 plan has identified an asteroid surface sample
return as one of the key developments needed to further our
understanding of the history and composition of our Solar System.

Work still in progress

Asteroids and comets are fascinating objects that can give or take life
on a planetary scale. Experts around the world are putting all their
energy and enthusiasm into deciphering the mysteries they carry within them.

With an early launch provisionally scheduled for 2011, Don Quijote will
serve as a 'technological scout' not only to mitigate the chance of the
Earth being hit by a large NEO but also for the ambitious journeys to
explore our solar system that ESA will continue to embark upon. The
studies now being carried out by European industry will bring the Don
Quijote test mission one step nearer.

Note for editors

Don Quijote is a NEO deflection test mission based entirely on
conventional spacecraft technologies. It would comprise two spacecraft
-- one of them (Hidalgo) impacting an asteroid at a very high relative
speed while a second one (Sancho) would arrive earlier at the same
asteroid and remain in its vicinity before and after the impact to
measure the variation on the asteroid's orbital parameters, as well as
to study the object. Secondary mission goals have also been defined,
which would involve the deployment of an autonomous surface package and
several other experiments and measurements.

For more information please contact:

Andrés Gálvez
Advanced Concepts and Studies Office
Andres.Galvez @ esa.int

Related links

* NEO
http://www.esa.int/SPECIALS/NEO/index.html
* First International Conference on Impact Cratering in the Solar System
http://www.rssd.esa.int/index.php?project=TOP &page=craters
* Two asteroid flybys for Rosetta
http://sci.esa.int/science-e/www/obj...objectid=34848

[NOTE: Images supporting this release are available at
http://www.esa.int/esaCP/SEMC43NFGLE_index_1.html ]