The shape of the STS-119/15A patch comes from the shape of a solar array viewed at an angle. The International Space Station (ISS), which is the destination of the mission, is placed accordingly in the center of the patch just below the gold astronaut symbol. The gold solar array of the ISS highlights the main cargo and task of STS-119/15A -- the installation of the S6 truss segment and deployment of S6's solar arrays, the last to be delivered to the ISS. The surnames of the crew members are denoted on the outer band of the patch. The 17 white stars on the patch represent, in the crew's words, "the enormous sacrifice the crews of Apollo 1, Challenger, and Columbia have given to our space program." The U.S. flag flowing into the space shuttle signifies the support the people of the United States have given our space program over the years, along with pride the U.S. astronauts have in representing the United States on this mission.
http://spaceflight.nasa.gov/gallery/images/shuttle/sts-119/html/sts119-s-001.html (Source PDF)
NASA/Crew of STS-119