Description of EVA 1
Spacewalk No. 1 Summary: Connect power, data and fluid umbilicals between S0 and P1, release Crew and Equipment Translation Aid (CETA) launch locks, install Spool Positioning Devices (SPDs), drag link removal, and install Node Wireless video system External Transceiver Assemblies (WETA).
Before Lopez-Alegria and Herrington emerge from the airlock, Wetherbee will use the shuttles robotic arm to grapple P1 and lift it from the payload bay, then hand it off to the stations Canadarm2, operated by Whitson and Bowersox. They will move P1 to the end of S0. After a claw attaches itself to P1 and draws it into position and bolts secure ends of the two segments, Lopez-Alegria and Herrington will emerge from the Joint Airlock and begin setting up for the first spacewalk.
Once he is clear of the airlock, Herrington will move to the rail lines along P1, where he will release CETA cart launch latches, a two-hour and 20-minute job. The task involves releasing a total of 24 bolts. First among them are the carts brake system bolts; their removal enables the CETAs brakes to be used.
Meanwhile, Lopez-Alegria will maneuver to the cable tray on the bottom of P1. Working from a portable foot restraint, he will open covers of cable trays on the lower sides of S0 and P1, then demate connectors on the S0 side from temporary attachment points and connect their free ends to receptacles on P1.
After that 45-minute task, Lopez-Alegria will begin installation of four 1-inch SPD on Flex Hose Rotary Coupler (FHRC) Quick Disconnects (QDs). He then will move inboard along P1 to the truss bay 12 and install two more 1-inch SPDs.
SPDs are devices that maintain the QDs, in ammonia lines that are part of the stations cooling system, in a position to enable them to function optimally. The installation of the 1-inch SPDs involves installing the aft part of the SPD, then moving a bail (QD valve) back about -in and installing the forward part of the SPD. This keeps the QD valve in a fixed position.
Back together again, Herrington and Lopez-Alegria move on to P1s starboard drag link, located on the forward face of the truss. They will work together to release that drag link, a large metal rod used as a launch restraint. Lopez-Alegria will release a bolt attaching the drag link to P1, while Herrington releases a similar bolt attaching the drag link to the keel. Lopez-Alegria takes the drag link to its stowage location on the P1 framework and attaches it with Herringtons assistance.
The processes are repeated on the P1 port drag link.
That 30-minute task completed, Lopez-Alegria moves to the cable tray atop P1. There he will make additional connections, opening thermal covers over cable trays atop S0 and P1, then demating connectors on the S0 side from temporary attachment points and connecting their free ends to receptacles on P1.
After that task, Lopez-Alegria and Herrington, who has done some additional work on the CETA, will combine on the final major task of the spacewalk, a two-hour installation on the Unity Node of the first WETA, designed to support spacewalkers helmet cameras.
Lopez-Alegria moves to the P1s starboard keel pin, retrieves the WETA stanchion and takes it to the Joint Airlock. There he and Herrington will spend about 15 minutes attaching the WETA to the stanchion. Herrington retrieves the WETA from its temporary airlock stowage position. While Lopez-Alegria holds the WETA in place, Herrington uses a pistol grip tool to secure a center jacking bolt and then two outer bolts.
Lopez-Alegria, with the WETA, and Herrington move to the installation location on the node. With help from Herrington, Lopez-Alegria secures it by driving a stanchion bolt. Subsequently he mates three stanchion power and data connectors to the node.
After about half an hour of EVA cleanup the spacewalkers will re-enter the airlock.
NASA TV Schedule for Flight Day 4
Orbit Item EST (GMT Minus 5)41 ENDEAVOUR CREW WAKE UP 08:20 AM (begins FD 4)41 ISS CREW WAKE UP 08:50 AM42 SHUTTLE RMS GRAPPLE OF P1 TRUSS 10:20 AM42 EVA 1 PREPARATIONS BEGIN 10:35 AM42 P1 TRUSS UNBERTH 10:50 AM42 SHUTTLE RMS HANDOFF OF P1 TRUSS 11:40 AM TO SSRMS44 P1 TRUSS INSTALLATION 02:00 PM45 EVA 1 BEGINS 03:20 PM48 SSRMS WALKOFF FROM MBS TO DESTINY 08:15 PM49 EVA 1 ENDS 09:50 PM49 MISSION STATUS BRIEFING 10:30 PM (time subject to change)51 ISS/ENDEAVOUR CREW SLEEP BEGINS 12:20 AM
Endeavour commander Jim Wetherbee describes the P1 truss:
"Of course, the backbone of the space station that holds the solar arrays on the space station, which we use for electrical power, and also holds the radiators to radiate the heat that we generate out into space, the backbone of the space station is the truss elements. And, we connect those elements together, piece by piece, and of course they all are able to fit inside the payload bay of the shuttle, and so we come up with the size of the individual elements of the truss, which are about 45 feet long and maybe about 15 feet wide."
"It's a girder-like structure, hexagonal in dimension. The "P" stands for port, it goes on the port side; it's very close inboard to the center, and so, it's the P1 Truss. Another crew will bring up the S1 Truss, which is on the starboard side. And, when we connect this truss to the S0, which is in the center attached to the Lab that's already up there, we will then connect first the mechanical latches and hooks and bolts and to give it structural rigidity."
"And then through spacewalks, our two spacewalkers will connect the fluid lines, the data connections, the electrical connections and the jumpers required to get across that place where we've just interfaced the two segments, and the segment that we have has a radiator segment with ammonia coolant lines that go into the radiator. And the theory is -- and it works very well, it's proven over the years of flying in space -- when you generate heat inside the vehicle and you dump it into the ammonia, it goes out into the lines and radiates off into space and so you have a habitat in space where you can control the living environment and radiate the heat and generate electrical power."
"On the forward side of the truss, very interesting, there's a railway and we use that with both the Mobile Transporter, that the Canadian arm is connected to, can move up and down the entire length of this girder and actually help us assemble, remotely, different parts of the space station. We also have a cart that people can get on, spacewalkers can climb on this cart and roll down this track on the outside of the truss. There are also different things on the outside of the truss -- some gyros, some ammonia systems for cooling and, of course, the radiator. Other trusses will have the solar arrays and the big gimbals that are required to slew the solar arrays and so they can track the Sun and generate more electricity more efficiently."
Pilot Paul Lockhart describes some of the major goals of the first spacewalk:
"Well, when Mike and John come outside the shuttle for the first time with the P1 truss there, our main thing is to make sure that we get power to the truss. Because it has electrical connections that have to be made in order to keep a lot of the critical avionics systems that are on it alive, thermally alive; in other words keep them thermally warm and stuff. So their main job when they come out is to make a lot of these connections that go between the S0 truss that it's attached to and the P1 truss properly mated, electrical and things of this nature, so that we can keep the avionics alive. And that's on a time clock, so that's basically our primary job: get out there and make those connections, and provide what we call keep-alive power to the P1 truss."
"They don't have to rush to do this, they've got several hours to do it. But, what happens is if they start to bring the P1 truss out of the cargo bay, the clock has started because when you bring it out of the cargo bay you no longer have electrical power connected to it and so it's basically exposed to the, to space and so isn't thermally protected. If we start to go out on our spacewalks and we find that a suit has a problem and then they have to come back in, and then have to go through this entire process of de-suiting, replacing something, then go through the checks one more time, we could lose a couple of hours in that whole process. And then we would be rushed in order to try and get the clocks connected, or try to get everything connected in time so that we meet the thermal clock."
"Plugging it in, making sure it's alive, and then there are a few other things that we're going to be doing. We have to move a couple of, some of the braces which were used to support the truss inside the cargo bay, one of which are called drag links but they're just support structures, those have to be moved and put out away as well as we're going to be positioning what is called a wireless antenna for the helmet cameras on the spacesuits."
"The spacesuits have three little lenses across the visor of the spacesuit itself, and these cameras are wireless, and they allow us in the space station and the space shuttle and on ground to see what the astronauts that are doing the spacewalks are actually working on. So they're really critical because they help provide us situational awareness in the cockpit, but they also provide documentary evidence of what the space the astronauts that are doing the spacewalks are doing. So as they tighten a bolt, we see that, we can film it, and so forth. But these wireless little cameras that are on the spacesuits of course have to have an antenna in order to transmit the little signal, and so what we're bringing out there on the spacewalk number one, on EVA 1 and also on EVA 2, are these transmitters, these wireless antennas, that will help transmit the signal."
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