WASHINGTON, March 15 (Xinhua) -- The U.S. space shuttle Discovery lifted off Sunday from Cape Canaveral, Florida. The following is a brief introduction to Discovery's STS-119 mission.
Discovery will deliver the International Space Station's (ISS) fourth and final set of solar array wings, completing the station's truss, or backbone. The arrays will provide the electricity to fully power science experiments and support the station's expanded crew of six in May.
The mission will feature three space walks to help install the S6 truss segment to the starboard, or right side of the station and the deployment of its solar arrays. The flight also will replace a failed unit for a system that converts urine to potable water.
The truss is a high-tech girder structure made up of 11 segments. It provides the backbone for the station, supporting the U.S. solar arrays, radiators and other equipment. To install the S6 truss segment, the station's robotic arm must extend its reach just about as far as it will go (about 57 feet), leaving it with very little room to maneuver. The S6 truss segment weighs a little more than 31,000 pounds. After S6 installation, the truss will be 335 feet long.
Each solar array wing has two 115-foot-long arrays, for a total wing span of 240 feet, including the equipment that connects the two wings and allows them to twist as they track the sun. Altogether, the station's arrays can generate as much as 120 kilowatts of usable electricity -- enough to provide about forty-two 2,800-square-foot homes with power. The addition of the S6 will nearly double the amount of power for station science -- from 15 kilowatts to 30 kilowatts.
The ISS' Urine Processing Assembly that removes impurities from urine in an early stage of the recycling process is not working. The entire Water Recovery System was delivered and installed during the space shuttle Endeavour's STS-126 mission in November, 2008. Astronauts were able to coax it into use by performing in-flight maintenance, but a distillation unit failed after Endeavour's departure.
The shuttle also will deliver Koichi Wakata, the first Japan Aerospace Exploration Agency's resident station crew member and bring back U.S. astronaut Sandra Magnus after more than four months aboard the orbiting laboratory.
