PARIS — Satellite builder Astrium Ltd. of Britain will build Europe’s Solar Orbiter science satellite under a contract signed April 26 with the European Space Agency (ESA) and valued at 300 million euros ($400 million).

The 1,800-kilogram satellite is scheduled for launch in 2017 aboard a United Launch Alliance Atlas 5 or Delta 4 rocket to be provided by NASA, which in addition to launch services is providing two instruments to the mission.

After a three-year cruise phase to include gravity-assist flybys of Earth and Venus, Solar Orbiter is scheduled to arrive in an orbit around the sun that will take it as close as 42 million kilometers from the sun’s surface. The satellite will remain in that orbit for at least three years, with a three-year extension possible.

The mission’s success will depend on the provision of instruments from NASA and several of ESA’s national member states, which under traditional ESA procedures must fund the science instruments from their own national budgets.

ESA’s total contribution to Solar Orbiter is expected to be nearly 500 million euros. To this will be added the cost of the instruments provided by individual European nations and NASA’s estimated $400 million contribution.

Solar Orbiter’s path around the sun exposes it to up to 13 times more thermal radiation than a satellite in Earth orbit. Among the innovations of the mission will be development of a heat shield that protects the satellite’s instruments while allowing them to make their observations, and solar array technology that functions while being exposed to such high temperatures.

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