Spaceflight Now STS-110

Atlantis arrives at space station to deliver truss
Posted: April 10, 2002

Shuttle skipper Michael Bloomfield guided Atlantis to a picture-perfect docking with the International Space Station Wednesday as the two spacecraft sailed 240 miles above southern China.

The linkup occurred at 12:05 p.m. EDT. The final hatch between the shuttle Atlantis and the station was opened about two hours later, allowing the shuttle's crew to mingle with their station counterparts for the first time.

Video from space showed Bloomfield floating into the station's Destiny laboratory module, welcomed aboard by station commander Yury Onufrienko. Bloomfield's crewmates quickly followed.

"We've got the entire crew together, it's great to see these guys, they look wonderful," Bloomfield radioed flight controllers at the Johnson Space Center. "And the station looks like it's in great shape."

The astronauts then floated down to the Russian Zvezda command module for a safety briefing from Onufrienko before beginning work to test the station's robot arm and to transfer supplies, equipment and fresh water to the station from Atlantis.

Thursday will see the S0 truss lifted out of Atlantis' payload bay using the station's Canadian-built robotic arm for installation to the Destiny module. That will be followed by the first spacewalk of Atlantis' mission as Steve Smith and Rex Walheim head out for a six-hour excursion.

Assisted by Expedition Four flight engineer Dan Bursch, shuttle astronaut Ellen Ochoa will be at the controls of the robot arm to mount the S0 truss to the station.

Ochoa will "move it out over the port side of the combined stack and then move the orientation around, come up over the top of the lab and then very precisely bring S0 down into what's called the module-to-truss-segment attach system, or MT-SAS," lead STS-110 station flight director Bob Castle said.

"You'll also see the lab cradle assembly being used. They'll align them very precisely, then activate a capture latch. The capture latch is actually on the lab, it looks like a claw. We'll capture S0, pull the structure together and then some alignment guides will line it up very precisely.

"That will all be done in the very first part of the crew day," Castle said. "We're timing it so just as we're finished with the capture latch operation, we'll be depressing the airlock to take the first EVA crew outside."

Smith, wearing a spacesuit with red stripes around the legs, is a veteran of five previous spacewalks while Walheim, wearing an unmarked white suit, will be making his first such excursion.

Smith will deploy the telescoping struts making up the forward bipods and Walheim will "rigidize" them like the legs of a camera tripod and bolt them to fittings on Destiny's hull. Smith, meanwhile, will open a trap door near the center of S0 and float part way into the truss to loosen a set of clamps allowing a large cable tray to deploy.

The cable tray is on the aft side of S0 facing the Z1 truss. It is known as the "rat's nest."

"It's buried between several modules and trusses and this area could be called the heart of space station for spacewalkers," Barclay said. "This is where many electrical and fluid lines mate between the modules."

Before making any such connections, however, circuit interrupt devices, or CIDs, will be installed and activated like circuit breakers to ensure no electricity is flowing through any of the cables.

Smith then will disconnect a set of diagnostic cables and release a pair of bolts to actually lower the tray before connecting 10 cables between the tray and connectors on Z1. On the front side of the truss, Walheim, occasionally assisted by Smith, will deploy another tray and make another 20 electrical connections.

If time is available, Smith will install two more CIDs inside the truss to allow future assembly crews to "break electrical circuits in the middle and reduce the amount of space station power down that's required during later assembly missions," Barclay said.

The final major goal of the first spacewalk is to power up the mobile transporter's internal heaters through the trailing umbilical system. Working together, Smith and Walheim will electrically connect the TUS and install about 20 feet of cable in guides along the mobile transporter's rails.

"So at the end of EVA-1, we've got two out of the four strut groups attached, so we're structurally in good shape for quite a while, we'll have all the power hooked up so all the avionics are up and working and we'll activate S0 and all the equipment on it that evening, after the crew finishes the EVA," Castle said.