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EVAs 1 and 2: Module installation, Dextre assembly BY WILLIAM HARWOOD STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION Posted: March 10, 2008 As with all spacewalks staged from the Quest airlock module, Linnehan and Reisman will spend the night in the airlock at a reduced pressure of 10.2 pounds per square inch as part of a standard, though lengthy, procedure to purge nitrogen from their bloodstreams. This helps prevent the bends after a day spent wearing NASA's 5 psi spacesuits. After exiting the airlock around 9:30 p.m. the day after docking, Linnehan and Reisman will make their way to Endeavour's cargo bay where they first will remove eight thermal blankets protecting the Japanese logistics module's common berthing mechanism. Moving to the front of the module, Reisman will unplug an electrical cable that supplied shuttle power to internal heaters. "Our job is to prepare the JLP for installation on the space station," Reisman said. "There are covers, kind of blankets that keep it warm in the coldness of space, that need to be removed before it gets installed. So we have to take off those covers and blankets. Then we also have to unplug (an) electrical cable that is used to keep it warm while it's inside the payload bay and that cable needs to be unplugged before it's lifted out, installed on the space station." Once that is completed, Doi, operating Endeavour's robot arm, will pull the module out of the cargo bay and begin the slow process of moving it to Harmony's upward-facing port. Linnehan and Reisman, meanwhile, will move up to the front of the station's power truss, make their way to the mobile base system to begin assembling Dextre. "We'll be focused on our work but, out of the corner of our eye, we'll see them taking this big module outside the payload bay," Reisman said. "It should be quite a sight watching that get installed as we go over to do the beginning, the first assembly work on Dextre. Our job is basically to put Dextre's hands on his arms."
DATE/EDT.......DD...HH...MM...EVENT 03/13/08 Thu 04:28 PM...02...14...00...Crew wakeup Thu 05:08 PM...02...14...40...EVA-1: 14.7 psi repress/hygiene break Thu 05:53 PM...02...15...25...EVA-1: Airlock depress to 10.2 psi Thu 06:18 PM...02...15...50...EVA-1: Campout EVA preps Thu 07:48 PM...02...17...20...EVA-1: Spacesuit purge Thu 08:03 PM...02...17...35...EVA-1: Spacesuit prebreathe Thu 08:53 PM...02...18...25...EVA-1: Crew lock depressurization Thu 09:23 PM...02...18...55...EVA-1: Spacesuits to battery power Thu 09:28 PM...02...19...00...EVA-1: Airlock egress Thu 10:08 PM...02...19...40...EVA-1: JLP unberth prep Thu 11:23 PM...02...20...55...EVA-1: OTCM 2 install 03/14/08 Fri 01:23 AM...02...22...55...EVA-1: OTCM 1 install Fri 01:58 AM...02...23...30...JLP unberth Fri 02:38 AM...03...00...10...SODF deploy Fri 02:43 AM...03...00...15...SPDM assembly preps Fri 03:08 AM...03...00...40...EVA-1: Cleanup Fri 03:33 AM...03...01...05...EVA-1: Airlock ingress Fri 03:53 AM...03...01...25...CBM first stage bolts Fri 03:53 AM...03...01...25...EVA-1: Airlock repressurization Fri 04:08 AM...03...01...40...Spacesuit servicing Fri 04:13 AM...03...01...45...CBM second stage bolts Fri 04:28 AM...03...02...00...Soyuz seatliner transfer to station Fri 05:08 AM...03...02...40...Alignment camera removed Fri 05:58 AM...03...03...30...JLP leak checks Fri 06:03 AM...03...03...35...JLP ungrapple Fri 07:58 AM...03...05...30...ISS crew sleep begins Fri 08:28 AM...03...06...00...STS crew sleep begins"The business end of Dextre if you like, Dextre's hands, also called the ORU tool changeout mechanisms (OTCMs), are equipped with force moment sensors," said Daniel Rey, Dextre integration manager for the Canadian Space Agency. "What makes Dextre able to perform these human scale tasks is the sense of touch it has and the automatic control that allows it to compensate for sets of forces, or moments, so that despite the crews commands, since they have no direct view and no direct force feedback except what's on their graphical display, Dextre will be able to prevent something from jamming." Replacing a failed space station component, he said, is similar to pulling out and re-inserting a drawer. "An insertion or an extraction is quite a delicate task, it's like trying to remove an old drawer from a chest that maybe is a bit damp and it requires that sense of touch that Dextre has built into it," Rey said. "Other features of the hand are the grippers ... and in the middle of the grippers, you notice there's a socket that can be extended identical to what you'd find on the EVA crew member's pistol grip tool. So it's a seven-sixteenths socket and that extends to unbolt an ORU." When fully assembled and attached to the station's robot arm, Dextre can be positioned next to a failed component. Using one of its hands to lock onto the station to provide rigidity, the other hand's grippers can lock onto the component, the socket wrench can unbolt it, the unit can be withdrawn and a replacement inserted. "There's a choreography that goes on with Canadarm2 to place Dextre in front of the work site," Rey said. "One arm will then be used to advance and stabilize the system. Since it's at the very end of a large, flexible arm 17 meters long, it's required to stabilize to avoid too many oscillations for the delicate maintenance tasks. So once the stabilization arm has acquired the stabilization fixture, the other arm is advanced. "We're looking forward to being used on orbit," Rey said. "We have every reason to believe that Dextre will meet and exceed its specifications the same as Canadarm2 did. But first, it has to be assembled. Dextre's two arms are mounted on either side of the Spacelab pallet with the robot's central torso in the center. After setting up their tools, Reisman will mount a foot restraint on the pallet while Linnehan clips his boots into a foot restraint on the end of the station's robot arm. He then will release two clamps to free the first OTCM, which will be attached to its arm with four mechanical fasteners and two electrical cables. To provide plenty of clearance for Doi, who will still be maneuvering the Japanese module into place using the shuttle's robot arm, Linnehan will get off the station arm and the second OTCM will be install while he and Reisman are free floating. The next day, the crew's flight day five, the astronauts will open the Japanese module and float inside to continue activation and outfitting. A block of time also is set aside for any focused heat shield inspections that might be required if any damage is spotted in the analysis of launch imagery and data.
DATE/EDT.......DD...HH...MM...EVENT 03/14/08 Fri 04:28 PM...03...14...00...Crew wakeup Fri 06:28 PM...03...16...00...ISS daily planning conference Fri 06:43 PM...03...16...15...Reisman's SOKOL suit leak check Fri 06:53 PM...03...16...25...JLP vestibule outfitting (part 1) Fri 07:13 PM...03...16...45...SOKOL suit drying Fri 07:28 PM...03...17...00...SSRMS grapples OBSS Fri 07:58 PM...03...17...30...SSMRS unberths OBSS Fri 08:13 PM...03...17...45...SSMRS hands OBSS off to SRMS Fri 08:48 PM...03...18...20...JLP outfitting (part 2) Fri 08:58 PM...03...18...30...SRMS grapples OBSS Fri 09:18 PM...03...18...50...SSRMS releases OBSS Fri 10:03 PM...03...19...35...Logistics transfers Fri 10:48 PM...03...20...20...EVA-2: Tool config Fri 10:58 PM...03...20...30...Crew meals begin 03/15/08 Sat 12:18 AM...03...21...50...JLP ingress Sat 01:48 AM...03...23...20...PAO event Sat 01:53 AM...03...23...25...Airlock preps Sat 03:58 AM...04...01...30...EVA-2: Procedures review Sat 06:38 AM...04...04...10...EVA-2: Airlock depress to 10.2 psi Sat 07:28 AM...04...05...00...STS crew sleep beginsLinnehan will be joined by Foreman for the mission's second spacewalk, an excursion expected to take about seven hours to complete. The goal is to attach both arms to Dextre's central torso, no small task when one considers each hand/arm unit would weigh about 775 pounds on Earth. After exiting the Quest airlock, Linnehan and Foreman will make their way back to the front side of the port 1 solar power truss and remove electrical cables that provided heater power. Each 11-foot-long arm features seven joints and thermal covers protection those joints must be removed, along with the clamps holding the arms and joints in place. Each arm will be temporarily stowed on a pallet fitting during work to ready them for attachment to the torso. At this point, Linnehan will get back on the station arm while Foreman assists as a free floater. "On the second EVA Mike and I will take the constructed arms that Garrett and I built from the previous EVA, which are still positioned on the sides of the SLP, but constructed so that the wrists and the hands, so to speak, are on the arms," Linnehan said. "At that point, Mike and I will take each of those arms off the sides of the pallet and we'll have to rotate the main body of the (robot) up and then plug those arms in on these giant outriggers. "And as I said before, it kind of looks like a mantis. That's when it takes on its big mantis kind of robot look. Once those arms are on, we have several other things that we have to do, such as install cameras, go down and put these special tool platforms and adaptors that allow it to hold equipment from the space station on the lower part of it and actually plug in and interface its own tools, take them out and work on things. All that takes a little bit more time at the end of the EVA and some of it involves me on the end of the arm, the robot arm flying around doing it and at other times both of us will be free floating, moving around all over the pallet and building stuff that way. "And we hope to finish all of that in two EVAs and, as I said, if for some reason we're slow or something doesn't go the way we like, then on the third EVA Bob Behnken and I would be able to finish most of that." The torso of the robot will be pivoted up about 60 degrees for the attachment of the arms and hands.
DATE/EDT.......DD...HH...MM...EVENT 03/15/08 Sat 03:28 PM...04...13...00...Crew wakeup Sat 04:08 PM...04...13...40...EVA-2: 14.7 psi repress/hygiene break Sat 04:53 PM...04...14...25...EVA-2: Airlock depress to 10.2 psi Sat 05:18 PM...04...14...50...EVA-2: Campout EVA preps Sat 06:23 PM...04...15...55...JLP outfitting Sat 06:48 PM...04...16...20...EVA-2: Spacesuit purge Sat 07:03 PM...04...16...35...EVA-2: Spacesuit prebreathe Sat 07:08 PM...04...16...40...SSRMS setup Sat 07:53 PM...04...17...25...EVA-2: Crew lock depressurization Sat 08:23 PM...04...17...55...EVA-2: Spacesuits to battery power Sat 08:28 PM...04...18...00...EVA-2: Airlock egress Sat 08:48 PM...04...18...20...EVA-2: Setup Sat 09:08 PM...04...18...40...EVA-2: SPDM arm 2 stow Sat 10:38 PM...04...20...10...EVA-2: SPDM arm 1 stow Sat 11:38 PM...04...21...10...EVA-2: SPDM arm install 03/16/08 Sun 01:28 AM...04...23...00...EVA-2 (Foreman): Cover removal; SLP cleanup Sun 01:28 AM...04...23...00...EVA-2 (Linnehan): SPDM cover removal Sun 02:38 AM...05...00...10...EVA-2: Cleanup Sun 03:08 AM...05...00...40...EVA-2: Airlock ingress Sun 03:28 AM...05...01...00...EVA-2: Airlock repressurization Sun 03:43 AM...05...01...15...Spacesuit servicing Sun 07:28 AM...05...05...00...STS crew sleep begins"I personally am going to be sighing a big sigh of relief at the end of EVA-2 when we get the OPCMs and both the arms installed," said Zeb Scoville, lead spacewalk officer. "There's a lot of really complex EVA activities going on there and coordination with some very fine robotics maneuvers required to get those installed. There have definitely been some challenges in ground training."
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