  We present Chandra X-ray observations of the radio-quiet QSO PG 2302+029.
This quasar has a rare system of ultra-high velocity (-56,000 km/s) UV
absorption lines that form in an outflow from the active nucleus (Jannuzi et
al. 2003). The Chandra data indicate that soft X-ray absorption is also
present. We perform a joint UV and X-ray analysis, using photoionization
calculations, to detemine the nature of the absorbing gas. The UV and X-ray
datasets were not obtained simultaneously. Nonetheless, our analysis suggests
that the X-ray absorption occurs at high velocities in the same general region
as the UV absorber. There are not enough constraints to rule out multi-zone
models. In fact, the distinct broad and narrow UV line profiles clearly
indicate that multiple zones are present. Our preferred estimates of the
ionization and total column density in the X-ray absorber (log U=1.6,
N_H=10^22.4 cm^-2) over predict the O VI 1032, 1038 absorption unless the X-ray
absorber is also outflowing at ~56,000 km/s, but they over predict the Ne VIII
770, 780 absorption at all velocities. If we assume that the X-ray absorbing
gas is outflowing at the same velocity of the UV-absorbing wind and that the
wind is radiatively accelerated, then the outflow must be launched at a radius
of < 10^15 cm from the central continuum source. The smallness of this radius
casts doubts on the assumption of radiative acceleration.
