9:59:59.000,9:59:59.000 So many of you have probably seen[br]the movie "The Martian." 9:59:59.000,9:59:59.000 But for those of you who did not,[br]it's a movie about an astronaut 9:59:59.000,9:59:59.000 who is stranded on Mars[br]and his efforts to stay alive 9:59:59.000,9:59:59.000 until the Earth can send a rescue mission[br]to bring him back to Earth. 9:59:59.000,9:59:59.000 Gladly, they do re-establish communication[br]with the character, astronaut Watney, 9:59:59.000,9:59:59.000 at some point, so that he's not as alone[br]on Mars until he can be rescued. 9:59:59.000,9:59:59.000 So while you're watching the movie,[br]and even if you haven't, 9:59:59.000,9:59:59.000 when you think about Mars,[br]you're probably thinking about 9:59:59.000,9:59:59.000 how far away it is and how distant. 9:59:59.000,9:59:59.000 And, what might not[br]have occurred to you is, 9:59:59.000,9:59:59.000 what are the logistics really like[br]of working on another planet? 9:59:59.000,9:59:59.000 Of living on two planets when 9:59:59.000,9:59:59.000 there are people on the Earth and[br]there are rovers or people on Mars? 9:59:59.000,9:59:59.000 So think about when you have friends,[br]families and co-workers in California, 9:59:59.000,9:59:59.000 on the West Coast[br]or in other parts of the world. 9:59:59.000,9:59:59.000 When you're trying to communicate[br]with them, one of the things 9:59:59.000,9:59:59.000 you probably first think about is -- 9:59:59.000,9:59:59.000 Wait, what time is it in California? 9:59:59.000,9:59:59.000 Will I wake them up? Is it okay to call? 9:59:59.000,9:59:59.000 So even if you're interacting[br]with colleagues who are in Europe, 9:59:59.000,9:59:59.000 you're immediately thinking about, 9:59:59.000,9:59:59.000 what does it take to coordinate[br]communication when people are far away? 9:59:59.000,9:59:59.000 So we don't have people on Mars right now,[br]but we do have rovers. 9:59:59.000,9:59:59.000 And actually right now, on Curiosity,[br]it is 6:10 in the morning on Mars. 9:59:59.000,9:59:59.000 We have four rovers on Mars.[br]The United States has put four rovers 9:59:59.000,9:59:59.000 on Mars since the mid-1990s, 9:59:59.000,9:59:59.000 and I have been privileged enough[br]to work on three of them. 9:59:59.000,9:59:59.000 So, I am a spacecraft engineer,[br]a spacecraft operations engineer, 9:59:59.000,9:59:59.000 at NASA's Jet Propulsion Laboratory[br]in Los Angeles, California. 9:59:59.000,9:59:59.000 And these rovers are robotic emissaries. 9:59:59.000,9:59:59.000 So, they are our eyes and our ears[br]and they see the planet for us 9:59:59.000,9:59:59.000 until we can send people. 9:59:59.000,9:59:59.000 So we learn how to operate[br]on other planets through these rovers. 9:59:59.000,9:59:59.000 So before we send people, we send robots. 9:59:59.000,9:59:59.000 So the reason there's a time difference[br]on Mars right now, 9:59:59.000,9:59:59.000 from the time that we're at 9:59:59.000,9:59:59.000 is because the Martian day[br]is longer than the Earth day. 9:59:59.000,9:59:59.000 Our Earth day is 24 hours because that's 9:59:59.000,9:59:59.000 how long it takes the Earth to rotate,[br]how long it takes to go around once. 9:59:59.000,9:59:59.000 So our day is 24 hours. 9:59:59.000,9:59:59.000 It takes Mars 24 hours and[br]approximately 40 minutes to rotate once. 9:59:59.000,9:59:59.000 So that means that the Martian day[br]is 40 minutes longer than the Earth day. 9:59:59.000,9:59:59.000 So teams of people who are operating[br]the rovers on Mars, like this one, 9:59:59.000,9:59:59.000 what we are doing is we are[br]living on Earth, but working on Mars. 9:59:59.000,9:59:59.000 So we have to think as if we are actually[br]on Mars with the Rover. 9:59:59.000,9:59:59.000 Our job, the job of this team, of which I'm a part of is to send commands to the rover to tell it what to do the next day. To tell it to drive or drill or tell her whatever she's supposed to do. So while she's sleeping -- and the rover does sleep at night because she needs to re-charge her battery and she needs to weather the cold Martian night.