The reason is that the Administration killed it a while ago, but NASA kept the people on the payroll because members of congress were like, "Wait a second... WE control the purse strings, not you." The Administration finally called NASA the other day and said you can't continue to work on this, or you can, but your people aren't getting paid for it.
So really, its not killed again, its: "What part of CANCELLED, don't you understand?" Extremely short-sighted? Yes. But perhaps with this upcoming solar storm, it might be best to keep our heads low for the next few years.