Some are over budget. Some are behind schedule. Some just don't work. The U.S. military's top weapons programs are among the world's most high-tech and costliest systems, with estimated acquisition costs totaling $1.6 trillion through fiscal year 2013. Defense made up about 20 percent of all U.S. spending in 2012, according to the Congressional Budget Office. Congress approaches a March 1 deadline to avert spending cuts of $1.2 trillion over nine years, half from defense. Here, in ascending order by price, are 10 of the military's most expensive weapons programs that could draw fire.

Read Bloomberg's four-part series on super-sized military spending here.