Q&A with Alvaro Gimenez, ESA’s director of science

Europe’s LISA Pathfinder mission crafted to demonstrate the ability to detect gravitational waves — theorized ubiquitous cosmic signals that have so far eluded discovery — has arrived at its operating post around the L1 Lagrange point nearly a million miles from Earth.

Engineers have spotted two small breaks in the treading on the left middle wheel on NASA’s Curiosity rover, one of six wheels that have moved the robot nearly 10 miles across the Martian surface since landing in August 2012.

As skywatchers and scientists converge on a transcontinental band of totality for Monday’s solar eclipse in the United States, engineers in Europe are building a unique pair of satellites to create artificial eclipses lasting for hours — a feat that that could be a boon for solar physicists but will escape the view of Earth-bound spectators.