PARIS — Europe’s space science decision-making body on Oct. 4 selected a satellite to be developed with NASA to fly closer to the sun than any previous spacecraft and a telescope to explore the universe’s expansion for development and launch in 2017 and 2019, respectively.

Meeting at European Space Agency (ESA) headquarters here, the Science Program Committee — which decides on space science missions within ESA’s budget parameters — approved Solar Orbiter and Euclid as ESA’s next Medium-class missions.

A third finalist, the Plato satellite to search for Earth-like planets around nearby stars, was left on the sidelines in the current competition.

If the experience to date with Solar Orbiter is any guide, however, Plato may one day find sufficient support for mission approval. Solar Orbiter has spent years in and out of Europe’s mission selection process. As now conceived, it is a bilateral endeavor with NASA, which will provide part of the satellite’s payload and an Atlas rocket for the 2017 launch. The satellite will study solar phenomena from an orbit just 41.9 million kilometers from the sun’s surface.

ESA has recently been affected by NASA budget pressures that have forced the U.S. agency to withdraw from previous cooperative endeavors. But Fabio Favata, head of ESA’s science planning office, said NASA and ESA have signed a memorandum of understanding on Solar Orbiter and that there are no indications of any problems.

In an Oct. 4 interview, Favata said ESA expects its share of Solar Orbiter to cost some 498 million euros ($672 million). When the NASA contributions, including the Atlas rocket, and science instruments provided by individual European governments are added in, Solar Orbiter’s total cost is expected to exceed $1 billion.

Because of its long history at ESA, Solar Orbiter has already been subjected to some of ESA’s mission validation procedures, and a prime contractor — Astrium UK of Britain — has been selected. A preliminary design review has begun, and full construction is expected to start in mid-2012.

French laboratories are expected to be major contributors to six of Solar Orbiter’s 10 instruments, the French space agency, CNES, announced Oct. 4. CNES will help finance the work, and also will contribute to Euclid, the agency said.

“Having backed these teams during the mission-evaluation phase and during the competition, CNES is ready to invest with the laboratories and other partner organizations to assure the success of these two missions,” Fabienne Casoli, chief of CNES’s department for the study of the universe, said in a statement.

ESA’s customary procedure for science missions is to divide responsibility with national organizations, which operate under national budgets. These laboratories build the payload instruments and then provide them to ESA, which finances the development and launch of the satellite, and its operation.

For each Medium-class mission ESA had set a target of 475 million euros as its share. The competition in 2007 began with five candidates, two of which were eliminated in the first round because of their high cost.

The Euclid mission, to study the universe’s quickening expansion and its catalyst, known as dark energy, had also raised questions about its likely cost when it first was proposed.

Now set for a launch aboard a Europeanized version of Russia’s medium-lift Soyuz rocket in 2019, Euclid is expected to cost ESA about 590 million euros, Favata said. As with Solar Orbiter, the satellite’s observing instruments will be furnished mainly by European laboratories financed by their national government space or research budgets, bringing the mission’s total cost to more than $1 billion.

Favata said Euclid’s 1.2-meter-aperture telescope, while advanced, is comparable to the two identical telescopes being designed for ESA’s universe-mapping Gaia satellite, set for launch aboard a European Soyuz rocket in 2013.

ESA is expected to issue a request for bids to prospective Euclid contractors in early 2012. The Science Program Committee will review the program’s status later that year after receiving precise estimates of the mission’s cost at completion and commitments from national laboratories on the sensors they will contribute.



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Peter B. de Selding was the Paris bureau chief for SpaceNews.