The Pentagon's advanced research arm plans to hold a proposers' day later this month for the second and third phases of a program to build and test a reusable booster system to cut the cost of space launches. In an April 7 special notice on Federal Business Opportunities, the Defense Advanced Research Projects Agency calls for interested industry to attend the April 29 proposers' day for Phase II and III of the XS-1 program, which intends to "design, build and...