I arrived at JPL around 6 pm tonight and already the parking lot was filling up with press. There's true suspense here. Will Curiosity land safely on Mars? When I was here years ago for the landing of Spirit, it seemed a forgone conclusion that the landing would go as planned. If the engineer had doubts, they kept them to themselves. But with this mission, there's a frank acknowledgement of the risk. MSL is huge and its landing system is brand new. And more than this one mission is at stake. As one NASA public information officer told me, the whole future of the planetary program hinges on success tonight.
Standing beside a model of the Curiosity rover.
Now, the die is cast. This morning Earth time the engineers at JPL spoke to MSL and sent their last message before landing. No earthling will speak to it again until it's on the surface of Mars. Throughout MSL's long journey, according to Nagin Cox, part of the mission's operations team, they send commands to the rover three times a week. Mainly what they get back is telemetry--power, attitude, velocity, etc.
So what did they say this morning? Did they send last minute instructions? "Don't talk to strangers!" "Get plenty of sleep!" "We love you no matter how things turn out. We know you did your best." Most of all, "If you meet any Martians, send pictures!"
No, none of these sweet parental admonitions. Simply they told it to change its timer so it won't expect another call from Earth for 93 hours. As Nagin Cox explained, if MSL expects a message and it doesn't come, it might think there's something wrong with its mechanisms for receiving the message. It might start fiddling with things, changing settings, adjusting antennas. And that could mess things up. We don't want MSL doubting itself at the last minute!
Once Curiosity is safely on the Martian surface, hopefully, communication will resume. They'll command the rover every day. The scientists and engineers will all shift over to Mars time. Already, Nagin is wearing two matches--one for Earth time, the other for Mars. But its not really necessary. There's even an app for that!
Nagin's watch collection--two for Mars, one for Earth.