Cosmic Visions: New Space Science Missions

Cosmic Visions: New ESA Space Science Missions Move Forward.

Under its Cosmic Vision initiative, the European Space Agency has selected three medium-sized science missions to enter the definition phase. Spacecraft to study dark energy, Earth-like exoplanets and our own Sun now have to prove that they can be built within the allocated budgets. 2011, just two of them will be retained to go forward for launches no earlier than 2017. This movie describes the three missions Euclid, Plato and Solar Orbiter.

Since the early '60s, ESA has excelled in pushing back the frontiers in space science: exploring the nearest planets and the most distant celestial bodies of our solar system; lifting the veil with powerful telescopes on galaxy and star formation and probing the most violent processes in the Universe; and better understanding its evolution since the Big Bang.

The three selected missions are the finalists from some 50 proposals which were whittled down to just six in late 2007 and submitted for industrial assessment. In February, the Agency's Science Programme Committee pared down the choice once more.

The project called Euclid will investigate key issues in physics, cosmology and general relativity. Until about 30 years ago astronomers thought the Universe was composed of ordinary matter -- protons, neutrons, electrons and atoms.

But the picture has changed dramatically: it is today assumed that ordinary matter only accounts for 4 % of the Universe, 20 % being dark matter and the remainder a mysterious dark energy.

The Euclid spacecraft will house a wide-field, high-precision telescope. For three years it will scan the entire sky, accurately measuring the effects of dark energy, believed to be the main driver of an accelerated expansion of the Universe. Euclid will also map in three dimensions the distribution of dark matter.

Following in the footsteps of the COROT and Kepler telescopes, the PLATO mission will address the 'holy grail' question of the existence of other Earth-like worlds.

Scanning the sky with an increased field of view, and by detecting the decrease in light as planets transit in front of their host star, the missaims to discover many more exoplanets, including those with orbital periods like our own. Observing brighter stars than previous missions, PLATO will be able to characterise planetary systems, the host stars and their planets at the same time.

Several missions -- such as Ulysses, SOHO, the Clusters, or Stereo -- have already studied our own Sun. The big difference with the third mission to be selected is, in a word: distance. Solar Orbiter will place itself as close to the Sun as Mercury itself, braving the intense heat and light, ten times more intense than that felt on Earth.

From an orbit allowing views of all sides of the Sun including its poles, the spacecraft is expected to deliver images of the Suns surface and data of the powerful magnetic fields, and high-resolution views of the powerful eruptions of solar particles that are spewed into space.

Given the extreme environment, Solar Orbiter is a considerable chanllenge, and will rely on much of the technology already developed for the Bepi-Colombo mission, ESA's probe to orbit Mercury.

Each mission has now entered the definition phase to validate the the configuration choices of their spacecraft and science instruments, the technologies to be used, their launch and operations scenarios.

But perhaps their greatest challenge probably will be to stay within their allotted 470 Million euro budgets knowing full well that ESA's selection process ist not over: in 2011 only two of the three missions -- and however merit-worthy -- can be retained to go-ahead.

• http://www.esa.int/