Where were you when Curiousity landed on Mars?

Of 13 previous attempts to land space probes on the Red Planet over the past four decades, nearly half failed or immediately lost contact. Those odds are enough to make tonight’s scheduled landing of NASA’s new rover, Curiosity, a tense, hold-your-breath moment. But the space agency’s plan to use a hovering, rocket-powered “sky crane” to lower the $2.5 billion, nuclear-powered robot 60 feet or so to the Martian surface almost guarantees it will be a suspenseful night at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Just to complicate things, the rover’s rapid-fire descent and landing is entirely automated. With more than 150 million miles separating Earth and Mars, round-trip communications between Curiosity and its far-off human overseers would take nearly half an hour. “Curiosity is on its own through all this,” says NPR science correspondent Joe Palca, who is monitoring the Mars mission in Pasadena. “Earth is too far away help if things go wrong.” The communications lag is also why we won’t know whether the rover has successfully landed until 1:31 a.m. ET on Monday, even though landfall is actually scheduled for 14 minutes earlier, at 1:17 a.m. ET.