1 00:00:01,251 --> 00:00:04,045 Hi, I'm Mike Lammers, a flight director at NASA's 2 00:00:04,045 --> 00:00:05,755 Johnson Space Center in Houston, Texas. 3 00:00:05,755 --> 00:00:08,758 And let's talk about spacewalks. 4 00:00:12,345 --> 00:00:15,098 EVA stands for extravehicular activity. 5 00:00:15,098 --> 00:00:18,643 It's a complicated term for what most of us think of as a spacewalk. 6 00:00:18,643 --> 00:00:23,732 What an Eva or a spacewalk is, is when the crew climbs into a space suit, 7 00:00:24,024 --> 00:00:29,029 leaves the safety of the space station and into the vacuum of space 8 00:00:29,029 --> 00:00:32,240 to do work, or to install enhancements for the space station. 9 00:00:32,240 --> 00:00:36,327 For the space station, spacewalks have been a critical element 10 00:00:36,327 --> 00:00:38,580 of first getting the space station built. 11 00:00:38,580 --> 00:00:40,123 Today, some of the things that we do 12 00:00:40,123 --> 00:00:44,085 with spacewalks for the station are both to grow its capability. 13 00:00:44,127 --> 00:00:47,839 For example, we have experiments on the outside that do 14 00:00:47,881 --> 00:00:50,717 get updated from time to time and then additionally, 15 00:00:50,717 --> 00:00:53,928 like you have to do at your home, we'll do maintenance where certain 16 00:00:53,928 --> 00:00:56,973 components wear out and the crew will go out and replace them. 17 00:00:57,140 --> 00:01:00,185 Usually for every minute that the crew is outside 18 00:01:00,185 --> 00:01:05,356 working will probably spend ten times that practicing on the ground, ensuring that 19 00:01:05,356 --> 00:01:08,610 the crew, when they get the instructions and the team on the ground, 20 00:01:08,610 --> 00:01:12,864 is working through the EVA with them, that they are as efficient as possible. 21 00:01:13,073 --> 00:01:17,827 Typically, we'll spend several months before actually executing a spacewalk, 22 00:01:17,827 --> 00:01:22,165 developing procedures and practicing inside the Neutral Buoyancy 23 00:01:22,207 --> 00:01:26,795 Laboratory, which is a very large, very deep swimming pool. 24 00:01:26,795 --> 00:01:31,800 And when you're in a spacesuit inside the Neutral Buoyancy Laboratory, 25 00:01:31,841 --> 00:01:35,929 there's a way that you can actually put weights in a certain method 26 00:01:35,929 --> 00:01:40,100 on the suit so that you will float either up nor down or sideways 27 00:01:40,100 --> 00:01:43,686 as you sit inside of the water, just like in space. 28 00:01:43,937 --> 00:01:48,817 Additionally, we have a full size mock up of the space station, 29 00:01:48,817 --> 00:01:54,280 and they're able to develop techniques to do tasks on the spacewalk. 30 00:01:57,617 --> 00:01:58,451 On EVA day. 31 00:01:58,451 --> 00:02:02,038 When it's time to go outside, the crew will get into their suits, 32 00:02:02,038 --> 00:02:05,083 they will activate them, and then they'll do what's called a pre 33 00:02:05,083 --> 00:02:08,211 breathe, where they purge the nitrogen from their blood 34 00:02:08,211 --> 00:02:10,922 because the suit operates at a lower pressure. 35 00:02:10,922 --> 00:02:13,174 Crew members have to go through a specific protocol 36 00:02:13,174 --> 00:02:16,719 in order that they don't get what is known with divers as the bends. 37 00:02:16,845 --> 00:02:21,141 Transitioning from the preparation side is when the crew actually 38 00:02:21,182 --> 00:02:24,185 egresses the airlock. 39 00:02:25,103 --> 00:02:28,815 The mission control personnel that support them discuss both 40 00:02:28,815 --> 00:02:33,027 what is happening right now in the spacewalk, as well as looking ahead 41 00:02:33,027 --> 00:02:36,197 so that we're ready for potentially changing what 42 00:02:36,197 --> 00:02:40,368 the crew is doing, or if they're actually moving faster than we expected. 43 00:02:40,410 --> 00:02:46,207 Some EVAs will place one of the crew members on the robotic arm. 44 00:02:46,207 --> 00:02:50,670 With the robotic arm, we can take large components or the astronaut 45 00:02:50,670 --> 00:02:55,967 themselves in what essentially is maneuver like a very large crane on Earth. 46 00:02:56,092 --> 00:02:59,179 Take a component and translate it 47 00:02:59,179 --> 00:03:02,849 in minutes to where they need to be to get to work. 48 00:03:02,932 --> 00:03:07,187 The robotic arm is a critical element, but also a lot of fun for the astronauts 49 00:03:07,187 --> 00:03:11,316 when they get to go for a ride. Spacewalks and the team 50 00:03:11,316 --> 00:03:15,403 that supports and develops them, as well as the astronauts that do the spacewalks, 51 00:03:15,445 --> 00:03:20,658 help keep the space station healthy and have for many decades. 52 00:03:20,700 --> 00:03:25,580 Looking forward, the skills that the team is learning doing spacewalks on the space station 53 00:03:25,747 --> 00:03:29,792 are informing our development of new suits, new techniques 54 00:03:29,792 --> 00:03:34,464 and new tools that can be used in future projects as humanity 55 00:03:34,464 --> 00:03:38,801 expands out into the solar system, including the moon and other planets.