  Control properties of the Kawahara equation are considered when the equation
is posed on an unbounded domain. Precisely, the paper's main results are
related to an approximation theorem that ensures the exact (internal)
controllability in $(0,+\infty)$. Following Rosier SIAM Simon (2000), the
problem is reduced to prove an approximate theorem which is achieved thanks to
a global Carleman estimate for the Kawahara operator.
