1 00:00:00,160 --> 00:00:04,240 S1: Good morning. Well, tomorrow morning around about 8:00 our time. Uh, 2 00:00:04,280 --> 00:00:07,160 S1: we'll see the return of Artemis two, hopefully safely. Uh, 3 00:00:07,160 --> 00:00:11,040 S1: we did say that it has to go through 3000°C 4 00:00:11,280 --> 00:00:14,600 S1: as it enters the Earth's atmosphere, and, uh, hopefully they'll 5 00:00:14,600 --> 00:00:17,079 S1: all be okay. Doctor, Chris James is a senior lecturer 6 00:00:17,079 --> 00:00:19,960 S1: at the centre for Hypersonics at the University of Queensland 7 00:00:19,960 --> 00:00:21,400 S1: and joins us. Good morning Chris. 8 00:00:22,280 --> 00:00:23,720 S2: Good morning. Happy to be here. 9 00:00:23,760 --> 00:00:27,040 S1: Now tell us about the return. Uh, we're saying earlier 10 00:00:27,040 --> 00:00:29,280 S1: that it's probably the most dangerous part of the whole trip. 11 00:00:29,280 --> 00:00:30,040 S1: Is that right? 12 00:00:31,120 --> 00:00:34,920 S2: Yeah, probably the the launch is obviously a bit dangerous, 13 00:00:34,920 --> 00:00:38,320 S2: but the re-entry is definitely the second most dangerous part. 14 00:00:38,320 --> 00:00:41,720 S2: So they're going to hit the atmosphere traveling about 11km 15 00:00:41,720 --> 00:00:44,760 S2: a second, so like 40km an hour. And then they 16 00:00:44,760 --> 00:00:47,240 S2: need to use the atmosphere as a brake to slow 17 00:00:47,280 --> 00:00:49,920 S2: themselves down so they can deploy the parachutes and land 18 00:00:49,920 --> 00:00:52,120 S2: safely back here on earth, hopefully. 19 00:00:52,159 --> 00:00:54,840 S1: So how does it withstand that type of temperature? What 20 00:00:54,840 --> 00:00:56,080 S1: kind of shield has it got? 21 00:00:56,880 --> 00:00:59,920 S2: Yeah. So they use what's called an ablative heat shield, 22 00:00:59,920 --> 00:01:03,720 S2: which is just an insulating layer, a very expensive specialist 23 00:01:03,760 --> 00:01:08,040 S2: material that absorbs some heat but tries to take the 24 00:01:08,040 --> 00:01:10,600 S2: heat and reject it back out to the atmosphere so 25 00:01:10,600 --> 00:01:13,800 S2: it doesn't go into the spacecraft and heat them all up. 26 00:01:13,959 --> 00:01:16,760 S1: Right. We were talking about one of the crafts on 27 00:01:17,120 --> 00:01:19,560 S1: take off. Some of that shield fell off and they 28 00:01:19,560 --> 00:01:23,319 S1: were worried about its re-entry. No dramas with this particular journey. 29 00:01:24,200 --> 00:01:27,080 S2: No, there shouldn't be that type of issue. Yeah. The 30 00:01:27,080 --> 00:01:29,840 S2: problem with the space shuttle was that the tiles were 31 00:01:29,840 --> 00:01:33,119 S2: exposed next to the rocket and they could get damaged. 32 00:01:33,240 --> 00:01:36,400 S2: The Artemis mission, it'll all be enclosed inside the rocket 33 00:01:36,400 --> 00:01:39,479 S2: when they launch. But the interesting part they had was 34 00:01:39,520 --> 00:01:44,199 S2: for Artemis one, which was the uncrewed test flight. Um, 35 00:01:44,240 --> 00:01:48,000 S2: NASA and other organizations, they model how these heat shields 36 00:01:48,000 --> 00:01:51,360 S2: respond very precisely. They test them. They do a lot 37 00:01:51,360 --> 00:01:53,880 S2: of work. But they found that the heat shield had 38 00:01:53,880 --> 00:01:56,920 S2: recessed more than they expected and big chunks had came 39 00:01:56,920 --> 00:01:58,600 S2: off and things like that. And they think they know 40 00:01:58,600 --> 00:02:01,040 S2: why it happened and they think they've dealt with that. 41 00:02:01,040 --> 00:02:03,880 S2: But in the craft did survive. Obviously Artemis one. But 42 00:02:04,200 --> 00:02:06,720 S2: hopefully there won't be any issues on the on the 43 00:02:06,720 --> 00:02:07,960 S2: entry on Saturday. 44 00:02:07,960 --> 00:02:09,720 S3: So how does this thing slow down enough for those 45 00:02:09,720 --> 00:02:12,240 S3: parachutes to deploy? Because what speed is it at when 46 00:02:12,240 --> 00:02:12,960 S3: they deploy? 47 00:02:14,000 --> 00:02:17,240 S2: Yeah. When they deploy the parachutes it's probably about Mach one. 48 00:02:17,240 --> 00:02:20,040 S2: So several hundred meters per second, which is still pretty fast, 49 00:02:20,040 --> 00:02:24,639 S2: probably about 1000km an hour, but it's much slower than 40,000. 50 00:02:24,680 --> 00:02:28,160 S2: So yeah, they, they slow down by basically the aircraft 51 00:02:28,160 --> 00:02:31,240 S2: is moving very fast, right? The spacecraft and the atmosphere 52 00:02:31,240 --> 00:02:34,040 S2: to us. You know, when we're doesn't feel very sick, 53 00:02:34,320 --> 00:02:37,560 S2: but when you're moving that fast, it is very thick, right? 54 00:02:37,600 --> 00:02:40,440 S2: So they just basically they fly like a big flying 55 00:02:40,440 --> 00:02:44,280 S2: brick as an aerodynamic as they can. And they use 56 00:02:44,280 --> 00:02:46,560 S2: the atmosphere as a brake to slow them down from 57 00:02:46,600 --> 00:02:49,280 S2: the atmospheric drag, right? Basically. 58 00:02:49,280 --> 00:02:51,480 S1: So will someone sail up to it when it hits 59 00:02:51,480 --> 00:02:53,280 S1: the water and knock on their door and they open 60 00:02:53,320 --> 00:02:55,240 S1: the the hatch? I mean, how does it work? 61 00:02:55,800 --> 00:02:57,760 S2: Yeah, yeah, I think it'd be just like, I'm not 62 00:02:57,800 --> 00:03:00,119 S2: exactly sure how the Artemis one works, but just like 63 00:03:00,160 --> 00:03:03,079 S2: you see in all those Apollo videos, they know they're 64 00:03:03,080 --> 00:03:06,280 S2: planning to land off the coast of San Diego. And 65 00:03:06,280 --> 00:03:08,360 S2: there'll be a there'll be a boat there, probably a 66 00:03:08,360 --> 00:03:11,240 S2: military boat waiting to pick them up. And they'll come 67 00:03:11,240 --> 00:03:13,519 S2: in with the helicopter and they'll knock on the door 68 00:03:13,520 --> 00:03:16,200 S2: and they'll bring them out and they'll grab the spacecraft 69 00:03:16,200 --> 00:03:18,120 S2: and they'll store it away to be put into a 70 00:03:18,120 --> 00:03:19,040 S2: museum one day. 71 00:03:19,080 --> 00:03:21,519 S1: Rightfully so. Are you space junkies. You'll be looking forward 72 00:03:21,520 --> 00:03:23,240 S1: to having a good sleep after all this. 73 00:03:23,800 --> 00:03:26,560 S2: Yeah, yeah, I think they will. I think they definitely will. 74 00:03:26,600 --> 00:03:28,200 S1: Yeah. Alright. Good on you, Chris. Thank you for that. 75 00:03:28,200 --> 00:03:29,880 S1: We'll follow it with interest tomorrow morning. 76 00:03:30,680 --> 00:03:32,480 S2: Yeah. Thank you so much, mate. Have a good day. 77 00:03:32,919 --> 00:03:35,240 S1: Doctor Chris James, their senior lecturer at the centre for 78 00:03:35,240 --> 00:03:37,160 S1: Hypersonics at the University of Queensland. 79 00:03:37,160 --> 00:03:39,200 S3: It's pretty amazing. Like the last Jetstar plane I got 80 00:03:39,200 --> 00:03:41,520 S3: was three hours delayed. But this thing's been away for 81 00:03:41,520 --> 00:03:43,840 S3: ten days. It'll land right on time in exactly the 82 00:03:43,840 --> 00:03:45,440 S3: right spot. Yeah, it's quite amazing. 83 00:03:45,440 --> 00:03:46,200 S1: Yeah, yeah.