  NSR superstring theory contains a tower of physical vertex operators
(brane-like states) which exist at non-zero pictures only, i.e. are essentially
mixed with superconformal ghosts. Some of these states are massless, they are
responsible for creating D-branes. Other states are tachyonic (called ghost
tachyons) creating a problem for the vacuum stability of the NSR model. In this
paper we explore the role played by these tachyonic states in string dynamics.
We show that the ghost tachyons condense on D-branes, created by massless
brane-like states. Thus the vacuum stability is achieved dynamically, as the
effective ghost tachyon potential exactly cancels the D-brane tension, in full
analogy with Sen's mechanism. As a result, from perturbative NSR model point of
view, massless and tachyonic brane-like states appear to live in a parallel
world, as the brane is screened by the tachyonic veil. We extend the analysis
to the brane-antibrane pair in AdS space and show that in this case due to the
effect of the ghost tachyon condensation one can construct extra
time-dimensional phenomenological models without tachyons and antibranes.
