[Robert A Cook PE]

Why did they stop?

May not have worked as well as as they wanted.

[lonestar1]

> Why did they stop?

Because Kennedy and Johnson wanted manned spaceflight to be reserved for NASA, for propoganda reasons. The Dyna-Soar prototype was 80% complete when the program was cancelled.

"Blackstar" is almost certainly fiction. There's no reason to believe the US has this type of capability -- yet -- but it should have.