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   72003
   We have obtained {\it ASCA} X-ray spectra of the canonical colliding-
   wind binary star WR 140 (WC7+OB) during the PV, AO1, AO5 and AO6
   intervals. We need continuing {\it ASCA} monitoring to measure the
   variability of the X-ray spectrum through the entire orbit. This X-ray
   lightcurve will provide the most accurate measure of the interaction
   region and redefine the physics of colliding-wind systems. The previous
   {\it ASCA} observations show that the spectrum has changed from a
   highly-absorbed, predominantly thermal spectrum to a less absorbed but
   {\it predominantly non-thermal} model. This is a very surprising
   result, not predicted in standard colliding wind models, and suggests
   that Fermi acceleration of particles at the wind shock boundary is
   important.
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