Q&A with Michel Denis, ExoMars flight director

Eight months after last hearing from the Opportunity rover, NASA officials announced the end of the craft’s 15-year mission Wednesday, closing out an ambitious chapter of Mars exploration that proved the Red Planet once harbored running water and demonstrated the promise of mobile robotic scouts to survey other worlds.

Sara Seager is an astrophysicist and planetary scientist at MIT, and she serves as deputy science director on NASA’s Transiting Exoplanet Survey Satellite, which aims to find planets around stars relatively close to the sun, searching for worlds that are ideal follow-up targets for missions like the James Webb Space Telescope.

During a fourth spacewalk Saturday to wrap up repairs of the coolant system in a $2 billion cosmic ray detector, Italian astronaut Luca Parmitano and Drew Morgan discovered a leak in one of eight coolant lines that were spliced into a new pump module during three earlier excursions. But Parmitano was able to tighten a fitting on the line and the astronauts were able to complete the repair work, setting the stage for the instrument to resume science operations.