Via the New York Times:
NASA’s latest Mars spacecraft, Maven, arrived Sunday evening to study the mystery of what happened to the planet’s air. After a 33-minute engine firing, mission controllers received acknowledgment at about 10:25 p.m. Eastern time that Maven was in orbit around Mars. After a six-week period to turn on and check systems on the spacecraft and to move it to its final orbit, Maven — the name is short for Martian Atmosphere and Volatile Evolution — is to take detailed measurements of the dynamics of Mars’s upper atmosphere. But first, it will have a sideshow, taking observations of a comet that, by rare happenstance, will make a close flyby of Mars on Oct. 19, passing within 82,000 miles. Mission managers have arranged to activate Maven’s eight scientific sensors by then.