February 28, 2011

4 Concepts Chosen For ESA’s Cosmic Vision 2015-2025

The European Space Agency (ESA) has selected four mission ideas for a launch that is scheduled for sometime in the early 2020s.

The mission ideas include investigations of black holes and general relativity, near-Earth asteroid sample-return, and studies of far-away planets orbiting other stars.

"Originally we had 47 proposals," Fabio Favata, head of ESA's Science Planning and Community Coordination Office, told BBC News. "Our working groups and the Space Science Advisory Committee did a great job in trimming the list when they had quite a number of missions that could all potentially make good candidates," he said.

"There was huge interest in this flight opportunity from right across the scientific community," said Favata. "The competition for this launch opportunity is the strongest to date for the ESA Science Program."

The call went out on July 29, 2010. The ESA asked members of the scientific community to solicit their proposals for a third medium-class mission (M3) within the long-term science plan known as Cosmic Vision 2015-2025.

The Advisory Structure to the Science Program peer reviewed all submissions and then forwarded them to David Southwood, ESA's Director of Science and Robotic Exploration.

Of the 47 proposals the ESA received, Southwood effectively narrowed them down to four missions that will undergo an initial Assessment Phase. Once the assessment is completed, a further down-selection will be performed, leading to a decision on which idea will get final approval for a mission.

"This selection of medium-class mission candidates is a major milestone in the definition of ESA's future science program," said Professor Southwood. "All of the missions selected for the Assessment Phase promise exciting scientific breakthroughs and choosing the mission that will be implemented will be a difficult process."

The four proposals chosen for the Assessment Phase are LOFT, EChO, MarcoPolo-R and STE-QUEST.

* LOFT, or Large Observatory For X-ray Timing, would hunt out fast-moving, high-energy environments that surround black holes, neutron stars and pulsars -- objects that can produce sudden and very rapid bursts of X-rays. By observing this emission, scientists would hope to answer questions related to the very basics of physics.

Scientists say a possible mission could probe the effects of matter entering ultra-strong gravitational fields and ultra-dense states. They also believe it could measure more accurately the mass and spin of black holes, and how they, and the galaxies that host them, formed.

* STE-QUEST -- Space-Time Explorer and Quantum Equivalence Principle Space Test -- like LOFT, would address some major physics conundrums. One objective would be to test "the equivalence principle," which supports several fundamental assumptions including the idea that gravity will accelerate all objects in a vacuum equally regardless of their masses or the materials from which they are made.

Apollo 15 astronaut Dave Scott famously demonstrated this principle when he dropped a hammer and feather on the Moon in 1971 and both items hit the surface at the same time. The STE-QUEST mission would put very sensitive instruments on an orbiter to do far more precise testing of whether gravity really is so blind or perhaps even varies on some scales.

* MarcoPolo-R is not a new idea. The mission would attempt to effectively collect and return an asteroid sample for detailed analysis in Earthen laboratories. The most primitive asteroids contain geochemistry not seen in Earth rocks because they are constantly recycled. As such, asteroids can give scientists a look into the conditions that existed in the early Solar System, and what matter made up the planets that formed billions of years ago.

* EChO, or Exoplanet Characterization Observatory, is a 1.2m telescope that would study planets circling far-away stars. In recent years, astronomers discovered hundreds of these so-called exoplanets, but little is known about them. EChO would observe the planets as they moved in front of the stars. From the way the light is attenuated, the telescope would be able to probe the atmospheres of these distant worlds.

Missions do not happen overnight. It takes literally months, years, and even decades to implement just one mission. The science also has to be compelling enough and the engineering requirements need to be realistic. The practicability of implementing these missions will be thoroughly investigated before a single best idea is chosen. It could take up to four years for a final decision to be made.

The ESA has about 645 million dollars set aside for its medium-class mission. Member states would individually cover the cost of building any instruments that go on a spacecraft.

The ESA currently has three planned medium-class missions under its Cosmic Vision program. M1 and M2 are currently in the final stages of the selection process and will go to two of the final three chosen mission plans -- Euclid, PLATO and Solar Orbiter. The final selection for those missions will be made later this year, with launches expected in 2017-18.

The ESA also has a Large Class program. This competition is also in the final stages of selection and is scheduled for a possible launch opportunity in 2020. If the winner of this program is delayed and cannot make the 2020 deadline, ESA would like M3 to be ready to take its place if necessary.


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