  The hot subdwarf B (sdB) stars form an homogeneous group populating an
extension of the horizontal branch (HB) in the ($T_{\rm eff}$--$\log g$)
diagram towards temperatures up to 40,000 K. The recent discovery that many of
them are multimode pulsators has triggered a large observational and
theoretical effort. We discuss the possibility of performing space-based
asteroseismology with {\em FUSE}, and we demonstrate that periodic luminosity
variations are already detectable in archival TTAG data of sdB stars. In
particular, we report on the {\em FUSE} observation of the pulsator PF
1219+534, which shows the presence of periodic variations at 6.9 mHz and 7.8
mHz, consistent with those reported from ground--based observations.
