The bow shocks of runaway O stars represent a potentially powerful
 laboratory for the study of dust processing via shocks.  The
 pre and postshock gas properties are measurable, as is the shock
 velocity.  What remains is to observe how the dust emissivity
 changes across the shock and relate it to the grain physics.

 IRAS observations revealed the presence of dozens of stellar wind
 bow shocks, but interpretation of their their surface photometry
 is complicated by the guaranteed presence of strong line emission
 as well as the very broad detector  bandpasses.  Deducing the
 continuum emissivity from the dust alone is thus not possible with
 existing data.

 We propose here to conduct full LWS scans to determine both
 the dust continuum and line emission from pre- and postshock
 locations in several bow shocks with different shock velocities.
 These data will provide the first well constrained test of current
 theories for dust modification in astrophysical shocks.  Certainly
 they will yield important empirical data characterizing the effects
 of shocks on interstellar dust.

 This study requires data at wavelengths not observable from
 the ground.  The KAO does not provide sufficient sensitivity.