You thought you needed to hit the snooze button this morning? The European Space Agency's Rosetta spacecraft has been sleeping for more than two years and is due to wake up today.
The Rosetta mission was launched from the Guiana Space Centre in French Guiana in March, 2004 and has been on a ten-year pilgrimage to Comet 67P/Churyumov-Gerasimenko. Rosetta's goal is to studey the comet up close as it enters the inner Solar System. If all goes well, it will be the first spacecraft to orbit a comet's nucleus and the first lander to do a controlled touchdown on the surface of a comet. As I've said before, comets are of great interest to us because they give us a window back in time to the formation of the Solar System, just as the Rosetta Stone allowed us to look back in time on Earth. Hence the name.
At 5:00am EST this morning, an "alarm clock" on board the spacecraft was set to go off, triggering it to come out of hibernation. ESA is now waiting for a confirmation signal from Rosetta once it has completed its wake-up checklist. Basically, Rosetta will phone home. However, this isn't our standard long-distance call. Rosetta is currently over 500 million miles away (~800 million kilometers) and even at the speed of light the signal will take almost 45 minutes to reach Earth - and that's after the spacecraft has got itself up and running again.
The signal will be quite weak, so ESA and NASA have teamed up to make use of the Deep Space Network's 70-meter Goldstone Antenna to ensure detection. All estimates point to a window between 12:30pm - 1:30pm EST as when we are most likely to get the message. If you thought Curiosity's "7 minutes of terror" was nerve-wracking, try five or six hours of terror! I can't imagine the stress, the anxiety, and the excitement levels the Rosetta team must be experiencing right now.