Japan’s space agency has approved a robotic mission to retrieve a sample from the Martian moon Phobos for return to Earth to begin full development for a planned launch in 2024, officials said Thursday. The Martian Moon eXploration, or MMX, spacecraft will attempt to return the first specimens from Phobos for analysis in laboratories on Earth, where scientists hope to trace the origins of the Martian moons to determine whether they were asteroids captured by Mars, or if they formed out of rocky debris generated from an ancient impact on Mars. The Japan Aerospace Exploration Agency and other Japanese government...