WEBVTT 00:00:00.000 --> 00:00:04.560 What kind of download speeds can you expect on the International Space Station? 00:00:04.560 --> 00:00:08.920 What about on Mars? Well, as you can imagine, it's not great. 00:00:08.920 --> 00:00:14.320 NASA communicates with its rovers on Mars and all of its deep space probes using the 00:00:14.320 --> 00:00:21.560 NASA Deep Space Network, or DSN, which unfortunately has some pretty serious limitations, due to 00:00:21.560 --> 00:00:25.520 being both based on radio waves and established in 1963. 00:00:25.520 --> 00:00:28.600 We'll see if you're still spry when you turn 60. 00:00:28.600 --> 00:00:33.720 To overcome these challenges, NASA's Jet Propulsion Laboratory is working on a new system 00:00:33.720 --> 00:00:40.160 called Deep Space Optical Communications, or DSOC, which is a laser system that might 00:00:40.160 --> 00:00:44.040 just be a game changer for interplanetary communication. 00:00:44.040 --> 00:00:47.040 And yes, they've already used it to send a cat video. 00:00:47.040 --> 00:00:51.240 Before we get into that, though, let's talk about the old system that DSOC needs to be 00:00:51.240 --> 00:00:56.880 better than. In many ways, the DSN is a scientific and engineering marvel. 00:00:56.880 --> 00:01:02.720 It uses three antenna arrays in California, Spain, and Australia in order to ensure coverage 00:01:02.720 --> 00:01:08.640 of the entire sky, and each array is located in a bowl-shaped mountainous area to shield 00:01:08.640 --> 00:01:16.280 it from as much radio interference as possible. The DSN uses a small subset of relatively high-frequency radio waves that can easily 00:01:16.280 --> 00:01:21.320 escape Earth's atmosphere, rather than bouncing off the ionosphere and coming right back, 00:01:21.320 --> 00:01:25.880 which can happen with low-frequency radio waves like those used for AM radio. 00:01:25.880 --> 00:01:30.640 Radio waves, being a form of electromagnetic radiation, move at the speed of light, so 00:01:30.640 --> 00:01:36.000 using lasers wouldn't really speed up communication in the strictly literal sense. 00:01:36.000 --> 00:01:40.160 They would, however, massively increase efficiency and bandwidth. 00:01:40.160 --> 00:01:45.840 The longer an electromagnetic wavelength is, the less information it can carry every second. 00:01:45.840 --> 00:01:50.680 Unfortunately, radio waves are the longest of the electromagnetic spectrum, and thus 00:01:50.680 --> 00:01:57.640 have the lowest carrying capacity. The lasers that desoc will use are in the near-infrared region, making them comparably 00:01:57.640 --> 00:02:01.400 tiny, and therefore allowing a much higher bandwidth. 00:02:01.400 --> 00:02:05.840 This means that an important communication from a nearby planet like Mars would take 00:02:05.840 --> 00:02:11.400 basically the same amount of time to physically reach Earth, between 3 and 22 minutes depending 00:02:11.400 --> 00:02:19.000 on where the two planets are in their orbits. But 10 to 100 times more information could be sent every second. 00:02:19.000 --> 00:02:23.240 A data package that would otherwise take days or months could instead be downloaded 00:02:23.240 --> 00:02:30.600 in a matter of hours. The hardware necessary to communicate via lasers is also lighter and more compact than 00:02:30.600 --> 00:02:35.480 comparable radio systems, meaning that it's easier to fit onto a relatively small probe 00:02:35.480 --> 00:02:41.040 or rover without excessively increasing the fuel needed to escape Earth's gravity well. 00:02:41.040 --> 00:02:45.640 You know, another problem with radio waves is that they tend to spread as they're transmitted. 00:02:45.840 --> 00:02:50.480 And that's not a problem when you want them to go everywhere, like with a television broadcast, 00:02:50.480 --> 00:02:55.000 but it means that the signal quickly becomes very weak once it travels any significant 00:02:55.000 --> 00:03:02.000 distance from its original source. And unfortunately, almost everything in space is very, very far away. 00:03:02.000 --> 00:03:06.440 With lasers, you still need to account for signal interference and distortion over long 00:03:06.440 --> 00:03:11.400 distances, but a coherent beam of energy is going to maintain its strength for longer. 00:03:11.400 --> 00:03:15.600 Think of it like the difference between a shotgun blast and a shot from a sniper rifle. 00:03:15.720 --> 00:03:22.880 The energy is more focused and it goes much farther. But infrared lasers do have physical limitations that radio waves don't. 00:03:22.880 --> 00:03:28.000 They require far more precise aim, and much like visible light, they can't travel through 00:03:28.000 --> 00:03:33.240 opaque objects. That's not a major problem, though, seeing as space is mostly empty. 00:03:33.240 --> 00:03:36.440 So when exactly will we be sending those cat videos? 00:03:36.440 --> 00:03:39.840 And what kinds of speeds can we expect within our own solar system? 00:03:39.840 --> 00:03:44.920 We might be able to send and receive laser transmissions, feline or otherwise, from as 00:03:44.920 --> 00:03:50.080 far as our solar system's inner asteroid belt as soon as 2029. 00:03:50.080 --> 00:03:55.040 That's because we've actually been developing the technology needed to catch Mars' telecommunications 00:03:55.040 --> 00:03:58.680 up to the 21st century for several decades. 00:03:58.680 --> 00:04:02.400 Scientists made their first major breakthrough with extraterrestrial laser communications 00:04:02.400 --> 00:04:08.840 in 1968, when they proved that the Surveyor 7 moon lander could detect lasers originating 00:04:08.840 --> 00:04:15.080 on Earth. In 1995, the Japanese Space Agency was able to establish two-way laser communication with 00:04:15.080 --> 00:04:20.000 its ETS-6 satellite at an astounding 1 megabit per second. 00:04:20.000 --> 00:04:25.520 By 2001, we had achieved laser communication between satellites, and by 2013, NASA used 00:04:25.520 --> 00:04:30.160 lasers to send an image of the Mona Lisa to a satellite orbiting the moon. 00:04:30.160 --> 00:04:33.960 The technology has progressed to the point where we can easily transmit data between 00:04:33.960 --> 00:04:39.680 Earth and low Earth orbit at not just megabits, but even many gigabits per second. 00:04:39.680 --> 00:04:45.180 On October 13th, 2023, NASA launched the Psyche Mission, a spacecraft bound for the 00:04:45.180 --> 00:04:50.480 asteroid 16 Psyche, which sits in the asteroid belt between Mars and Jupiter. 00:04:50.480 --> 00:04:55.000 That mission will also be an important test for the technology behind DSOC, as the Psyche 00:04:55.000 --> 00:04:59.940 spacecraft will encode its data and send it back to Earth using infrared lasers. 00:04:59.940 --> 00:05:04.840 The Psyche mission won't arrive at its destination until 2029, but it's already made one successful 00:05:04.840 --> 00:05:14.080 test of the new communication system. On December 11th, 2023, from over 19 million miles away, the spacecraft sent back an ultra-high-definition 00:05:14.080 --> 00:05:19.880 video of an orange cat, reportedly named Tater, playing with the dot of a laser pointer. 00:05:19.880 --> 00:05:25.120 The hope is that Psyche's DSOC will be able to send data back at 2 megabits per second 00:05:25.120 --> 00:05:30.200 even after it reaches its destination, far beyond Mars, demonstrating the viability of 00:05:30.200 --> 00:05:33.960 laser communication even in the farthest reaches of the solar system. 00:05:34.080 --> 00:05:38.080 Wealthy. Inner solar system for now. But we're coming for you, Neptune. 00:05:38.080 --> 00:05:44.160 Hey, that was a Techquickie! Thanks for watching! Like, follow, and subscribe if you feel like it, and check out our other videos. 00:05:44.160 --> 00:05:47.880 Like this one, on the world's longest wireless internet range. 00:05:47.880 --> 00:05:50.380 There may be lasers involved. I haven't seen it. I don't know.