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In November 2005, we observed the moons of Mars using the Arecibo 2380-MHz (13-cm) radar, obtaining a result for the OC radar albedo of Phobos (0.056 [+ or -] 0.014) consistent with its previously reported radar albedo and implying an upper bound on its near-surface bulk density of 1.6 [+ or -] 0.3 g [cm.sup.-3]. We detected Deimos by radar for the first time, finding its OC radar albedo to be 0.021 [+ or -] 0.006, implying an upper bound on its near-surface density of 1.1 [+ or -] 0.3 g [cm.sup.-3], consistent with a high-porosity regolith. We briefly discuss reasons for these low radar albedos, Deimos' being possibly the lowest of any Solar System body yet observed by radar. Keywords: Mars, satellites; Radar observations; Regoliths

Radar echoes from Earth co-orbital Asteroid 2002 AA29 yield a total-power radar cross section of 2.9 x [10.sup.-5] [km.sup.2] [+ or -] 25%, a circular polarization ratio of SC/OC = 0.26 [+ or -] 0.07, and an echo bandwidth of at least 1.5 Hz. Combining these results with the estimate of its visual absolute magnitude, [H.sub.V] = 25.23 [+ or -] 0.24, from reported Spacewatch photometry indicates an effective diameter of 25 [+ or -] 5 m, a rotation period no longer than 33 min, and an average surface bulk density no larger than 2.0 g [cm.sup.-3]; the asteroid is radar dark and optically bright, and its statistically most likely spectral class is S. The [H.sub.V] estimate from LINEAR photometry (23.58 [+ or -] 0.38) is not compatible with either Spacewatch's [H.sub.V] or our radar results. If a bias this large were generally present in LINEAR's estimates of [H.sub.V] for asteroids it has discovered or observed, then estimates of the current completeness of the Spaceguard Survey would have to be revised downward. Keywords: Asteroids; Radar; Photometry