Shuttle, Station Missions Ahead Are Most Challenging Ever
Johnson Space Center, Houston
|Aug. 7, 2006|
"The flights ahead will be the most complex and challenging we've ever carried out for construction of the International Space Station in orbit," said Mike Suffredini, NASA station program manager. "The station literally becomes a new spacecraft with each assembly mission, and that will be true starting this year with dramatic changes in its cooling and power systems, habitable volume, utilization capability as well as its appearance."
The station is nearly halfway through assembly. The next four flights will bring new truss segments, massive structural girders, to the complex. The new segments will increase the mass of the station by almost 40 tons. Two of the trusses include huge sets of solar array wings, totaling more than 17,000 square feet and more than 130,000 solar cells. The new segments include giant rotary joints to allow the tips of the station "backbone" to move as the massive panels track the sun.
Together, the new arrays will add 50 kilowatts of power for the complex. The increased electrical power will set the stage for the addition of European and Japanese laboratories that will far surpass any previous research capability in space.
The installation of the new truss segments and unfurling of the arrays require unprecedented robotic operations. Those operations will use the shuttle and station's Canadian-built mechanical arms to delicately maneuver school bus-sized station components into place. The operations will rely heavily on the station's mobile transporter, a sort of space railway that positions the robotic arm along the truss to install the components.
Later this year, the station and shuttle crews face a unique challenge to activate a permanent cooling system and the new power sources. They must rewire the orbiting laboratory and change its electrical supplies without interrupting the continuous operation of any of its critical systems. Once the power grid is in place, additional shuttle flights will launch a connecting node and the European and Japanese laboratories.
"The assembly of the station on these flights has no parallel in space history," Suffredini said. "We have planned, studied and trained for these missions for years. We know they will be hard, and we may encounter the unexpected. But we are eager to get started, and there is tremendous excitement building in NASA and among our international partners."
The station's assembly and maintenance in orbit, the long-duration spaceflight experience gained aboard the complex, and the research into the effects of long spaceflights contribute to NASA's plans for future missions to return to the moon and travel beyond.
The current station represents only a fraction of its eventual capabilities. Between now and station completion:
* The volume and mass of the station will more than double. The space station will be larger than a five-bedroom house with a cabin volume of 33,023 cubic feet. When completed, it will have a mass of almost a million pounds.
* The number of research facilities on the complex will more than triple. The percentage of total power dedicated to research will increase by 84 percent.
* The total power generated by the complex will almost quadruple.
* The station's truss, currently 134 feet long, will grow to 354 feet, the longest man-made object to fly in space.
* To construct the station, more than 100 international space flights will have been conducted on five different types of vehicles launched from four different countries.
* More than 140 spacewalks, totaling nearly 800 hours, dedicated to assembly and maintenance of the space station will have been completed. That is more spacewalks than were conducted in all of U.S. space history before construction of the station began. * There have been 115 space shuttle flights, of which 18 were dedicated to the space station. With 15 remaining assembly flights planned to the station, more than one-quarter of all shuttle flights will have been dedicated to station assembly.
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