1 00:00:00,100 --> 00:00:09,180 [ music ] 2 00:00:09,200 --> 00:00:13,080 Narrator: NASA's newest Mars spacecraft, MAVEN, is currently on a mission 3 00:00:13,100 --> 00:00:18,180 to determine how Mars lost its early atmosphere, and with it, its water. 4 00:00:18,200 --> 00:00:23,170 Jakosky: The questions that MAVEN is trying to answer deal with the history of the Martian climate. 5 00:00:23,190 --> 00:00:27,830 From the previous missions we have a lot of evidence that that climate has changed over time, 6 00:00:27,850 --> 00:00:32,210 that early Mars was warmer, wetter than present-day Mars. 7 00:00:32,230 --> 00:00:36,440 What we're trying to answer with MAVEN is, "Where did all that water go?" 8 00:00:36,460 --> 00:00:43,600 "Where did the carbon dioxide from an early thick atmosphere go?" And we're doing this by studying the top of the atmosphere. 9 00:00:43,620 --> 00:00:48,290 Since we are the first mission really looking at all pieces of the puzzle on the upper atmosphere, 10 00:00:48,310 --> 00:00:52,830 almost everything we're seeing and how it relates to everything else is brand new. 11 00:00:52,850 --> 00:00:58,250 As an example, one of the things we measured very early in the mission, right after we went into orbit, 12 00:00:58,270 --> 00:01:04,020 before we even got into our final science mapping orbit, was the distribution of hydrogen, 13 00:01:04,040 --> 00:01:11,020 oxygen, and carbon as a cloud surrounding the planet, the very extended upper atmosphere. 14 00:01:11,040 --> 00:01:19,280 Narrator: In this ultraviolet image, carbon and oxygen cling tightly to Mars, while hydrogen, the lightest element, extends well above the planet. 15 00:01:19,300 --> 00:01:25,830 Understanding the escape of hydrogen is important, because hydrogen is the primary ingredient in water. 16 00:01:25,850 --> 00:01:29,230 While previous Mars orbiters have peered down at the planet's surface, 17 00:01:29,250 --> 00:01:36,780 MAVEN is spending part of its time gazing at the stars, observing the Martian atmosphere through a series of stellar occultations. 18 00:01:36,800 --> 00:01:40,480 Jakosky: The imaging ultraviolet spectrograph, the IUVS instrument, 19 00:01:40,500 --> 00:01:45,900 can determine properties of the upper atmosphere all the way down to the lower atmosphere, 20 00:01:45,920 --> 00:01:51,330 by looking at a star, as the star sets behind the planet as seen from the spacecraft. 21 00:01:51,350 --> 00:01:59,580 And by looking at the diminution, the weakening of the starlight as it sets, we can measure the composition of the upper atmosphere. 22 00:01:59,600 --> 00:02:03,980 Narrator: The relative motion of the stars allows MAVEN to look at columns of the atmosphere, 23 00:02:04,000 --> 00:02:07,230 revealing how its composition changes with altitude. 24 00:02:07,250 --> 00:02:14,190 At the same time, MAVEN's orbit passes close to the Martian polar caps, giving it north-to-south coverage of the planet. 25 00:02:14,210 --> 00:02:19,180 Mars itself rotates once a day beneath MAVEN, providing east-to-west coverage. 26 00:02:19,200 --> 00:02:22,980 This combination allows MAVEN to observe the entire atmosphere. 27 00:02:23,000 --> 00:02:30,780 Jakosky: My goal with MAVEN is to put together a data set that the Mars science community can spend the next decade or two working on. 28 00:02:30,800 --> 00:02:36,180 We're making very few measurements that have never been made at all before at Mars, 29 00:02:36,200 --> 00:02:41,400 but what we're doing is, we're making them in parts of the atmosphere where they haven't been measured, 30 00:02:41,420 --> 00:02:47,600 we're making comprehensive measurements for a full year rather than, for example with the Viking lander, 31 00:02:47,620 --> 00:02:52,980 a one-time entry, one profile. We're going to get hundreds and hundreds of profiles, 32 00:02:53,000 --> 00:02:58,460 and be able to see how the upper atmosphere responds to the changing solar conditions, 33 00:02:58,480 --> 00:03:05,120 and really put together a picture of the upper atmosphere that we haven't been able to put together before. 34 00:03:05,140 --> 00:03:12,650 [ music ] 35 00:03:12,670 --> 00:03:26,470 [ satellite beeping ]