Europe’s Mars Express, toting the British-built Beagle 2 lander, remains set for launch June 2 and is to be the opening volley in a salvo of Mars robotic spacecraft heading outward to that compelling world during the coming weeks. Meanwhile, as Mars Express awaits departure, NASA’s dual Mars Exploration Rovers are being prepped for sendoff. Now simply labeled MER-A and MER-B, the first craft is slated for dispatch from Florida’s Space Coast no earlier than June 8. The second rover is to roar skyward on June 25.