WEBVTT Kind: captions Language: en 1 00:00:00.080 --> 00:00:04.839 The Voyager 1 space probe is the furthest man-made object from Earth, and the fastest. 2 00:00:04.839 --> 00:00:07.920 But right now, it is moving towards us. 3 00:00:07.920 --> 00:00:09.530 Relatively speaking. 4 00:00:09.530 --> 00:00:12.719 This is the control room for NASA’s Deep Space Network 5 00:00:12.719 --> 00:00:16.810 and the scientists here still listen for the signals that Voyager is sending. 6 00:00:16.810 --> 00:00:21.250 Deep Space Network is a collection of antennas around the world 7 00:00:21.250 --> 00:00:23.580 that we use for tracking deep space missions. 8 00:00:23.580 --> 00:00:28.220 We provide commands to the spacecraft, so y’know, “turn left at the next corner” 9 00:00:28.220 --> 00:00:29.220 kinds of things, right? 10 00:00:29.220 --> 00:00:30.500 Little more complicated than that. 11 00:00:30.500 --> 00:00:33.000 Turn the instrument on, turn the instrument off, software updates. 12 00:00:33.000 --> 00:00:35.200 The most important reason for sending the thing out there 13 00:00:35.200 --> 00:00:39.530 is to get the science data back, and so the instruments are taking 14 00:00:39.530 --> 00:00:44.540 visible pictures, infrared pictures, measuring particles in the case of Voyager. 15 00:00:44.540 --> 00:00:47.890 We need to get that data back down and distribute it to the scientists. 16 00:00:47.890 --> 00:00:50.940 The Deep Space Network’s three stations cover the whole sky. 17 00:00:50.940 --> 00:00:53.840 Any mission more than 30,000 km away from Earth 18 00:00:53.840 --> 00:00:56.690 is visible to at least one station all the time. 19 00:00:56.690 --> 00:00:59.940 Geostationary orbit, where we keep most of our communication satellites, 20 00:00:59.940 --> 00:01:01.100 is further away than that. 21 00:01:01.100 --> 00:01:03.620 We really have three complexes around the world: 22 00:01:03.620 --> 00:01:10.050 Madrid in Spain, Goldstone here in California, and the Canberra complex in Australia. 23 00:01:10.050 --> 00:01:13.130 We typically don’t track things that go over the pole because 24 00:01:13.130 --> 00:01:16.730 the types of missions that we deal with are in deep space 25 00:01:16.730 --> 00:01:17.950 and tend to be in the ecliptic. 26 00:01:17.950 --> 00:01:20.720 If you look at the solar system, where the Sun is, 27 00:01:20.720 --> 00:01:24.000 and where the planets are that are revolving around the sun, 28 00:01:24.000 --> 00:01:26.770 they all tend to be more or less in one plane. 29 00:01:26.770 --> 00:01:30.050 That launch along the plane of the solar system, along the ecliptic, 30 00:01:30.050 --> 00:01:32.740 is the reason that Voyager is getting closer to Earth right now. 31 00:01:32.740 --> 00:01:36.770 Yes, Voyager is always moving away from the sun, but sometimes the Earth’s orbit 32 00:01:36.770 --> 00:01:41.070 means that our planet is travelling in roughly the same direction only faster. 33 00:01:41.070 --> 00:01:42.120 So we’re catching up. 34 00:01:42.120 --> 00:01:44.180 Of course, we’ll get pulled back in our elliptical orbit 35 00:01:44.180 --> 00:01:46.350 so it’ll even out when we go back the other way. 36 00:01:46.350 --> 00:01:50.400 In terms of checking in with spacecraft, I think with Voyager for example, 37 00:01:50.400 --> 00:01:53.479 we probably downlink from them almost every day. 38 00:01:53.479 --> 00:01:57.210 Because again, there’s a lot of good data, but when you are only coming at 160 bits per second, 39 00:01:57.210 --> 00:02:00.480 it takes a long time to get that data off the spacecraft. 40 00:02:00.480 --> 00:02:05.260 The signal has to be, in some sense, above the noise level for us to see it. 41 00:02:05.260 --> 00:02:08.530 You first of all just try to filter the noise out as much as possible, 42 00:02:08.530 --> 00:02:10.890 just from a frequency standpoint. 43 00:02:10.890 --> 00:02:14.260 My signal occupies this much spectrum in frequency, 44 00:02:14.260 --> 00:02:17.500 I don’t want to let in any more noise than what’s there. 45 00:02:17.510 --> 00:02:20.010 I want to correlate the signal that’s coming down 46 00:02:20.010 --> 00:02:22.100 with what I think that signal looks like. 47 00:02:22.100 --> 00:02:24.930 You got to take advantage of what you know about the signal 48 00:02:24.930 --> 00:02:29.850 and use those characteristics as best you can to extract it from the noise. 49 00:02:29.850 --> 00:02:34.610 Voyager 1 is carrying radioisotope thermoelectric generators, RTGs. 50 00:02:34.610 --> 00:02:36.920 It’s powered by radioactive decay. 51 00:02:36.920 --> 00:02:40.680 And there’s enough power there to last until around 2025. 52 00:02:40.680 --> 00:02:45.819 After that, the craft will go dark, carrying a message forward into interstellar space 53 00:02:45.820 --> 00:02:50.040 for… well, we don’t know where, or when, or even who. 54 00:02:50.040 --> 00:02:52.400 If there was enough light being bounced off of it, 55 00:02:52.410 --> 00:02:57.819 you might be able to see it with a telescope, but it’s so far away, and so dim, 56 00:02:57.819 --> 00:03:00.830 without a radio signal coming from Voyager at all, 57 00:03:00.830 --> 00:03:04.600 there’s no way that we, the DSN, would be tracking it. 58 00:03:04.600 --> 00:03:08.380 And so I think that’s pretty much the end, once it goes dark. 59 00:03:08.380 --> 00:03:11.620 Thank you very much to all the team at NASA, the Jet Propulsion Laboratory, 60 00:03:11.620 --> 00:03:13.260 and here at the Deep Space Network. 61 00:03:13.260 --> 00:03:16.680 Pull down the description for more about them, and about their missions.