The European Space Agency says its next two large science missions will study the hot and energetic universe and search for elusive gravitational waves.

Both missions will involve fundamental astrophysics and cosmology by studying in detail the processes crucial to the large-scale evolution of the universe and its underlying physics, the ESA said in a release from its Paris headquarters Thursday.

L2, the second Large-class mission in ESA's Cosmic Vision science program, is expected to be pursued with an advanced X-ray observatory that will examine how and why ordinary matter assembles into the galaxies and galactic clusters that we see today, and how black holes grow and influence their surroundings.

The L3 mission will study gravity in the universe, searching for ripples in the fabric of space-time created by celestial objects with very strong gravity, such as pairs of merging black holes, the ESA said.

The missions were selected from 32 proposals received after the ESA issued a call to the European science community to suggest the next scientific themes that should be pursued by its Cosmic Vision program.

"We had a difficult task in deciding which scientific themes to choose from all of the excellent candidates, but we believe that missions to study the hot, energetic universe and gravitational waves will result in discoveries of the greatest importance to cosmology, astrophysics, and physics in general," Catherine Cesarsky, chairwoman of the ESA's Senior Survey Committee, said.

Although the launch dates for both missions are more than a decade away, preparation activities will start very soon, the ESA said.