More than once my friend. And if thing works - why should you care. Buran was a very top tech, superior to US shuttles in so many ways (capable of fully unmanned two-way trip for starters). The whole "Energia" complex is still unmatched by any spacecraft system in the world. The loss of this tech is unrecoverable though.
>capable of fully unmanned two-way trip for starters
Nope. Technology and precision required for fully-automatic landing of such aircraft becomes available only now. That particular landing was remote-controlled by a closely following plane.
