Companies compete to fill void left by space shuttle

New York Times : Last year the Obama administration pushed through an ambitious transformation for NASA: canceling the Ares I rocket, which was to be the successor to the current generation of space shuttles, and turning to the commercial sector for astronaut transportation. So far, most of the attention in this new commercial space race has focused on Boeing and Space Exploration Technologies Corp, or SpaceX. But they are not the only competitors seeking to provide space taxi services, a program that NASA calls commercial crew. One potential competitor is Sierra Nevada Space Systems, which has built the Dream Chaser space plane.