European scientists, hoping for a sign their Mars lander Beagle 2 arrived safely, anxiously awaited Friday’s attempt by a U.S. orbiter to pick up a communication after more than 36 hours of silence from the surface of the Red Planet. “It’s like sending somebody a love letter, and you know they got it and you’re waiting for a response,” said Professor Colin Pillinger, the day after the tiny craft was supposed to have landed on the surface of Mars, opened its solar panels and called home.