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Engineering telemetry data and lunar surface photographs by Surveyor 1 have been evaluated for information on the mechanical properties of the lunar surface material at the Surveyor 1 landing site. Based primarily on photographic evidence, estimates of soil density, cohesion, and other soil characteristics are presented. Also, the mechanisms in which the lunar material is believed to have failed under the footpad impacts are discussed. Because dynamic soil reactions cannot be interpreted directly from the available data, a comparative study using computer-simulated landings was initiated. Preliminary results of this study, which is still in progress, are presented. OBSERVATIONS AND EXPLANATIONSThe interpretation of the lunar surface properties discussed here is based on (1) 801

The surface material at the Surveyor 5 site is granular and slightly cohesive. Spacecraft footpads plowed trenches in this material as the spacecraft slid during landing. For a compressible soil model, a static bearing capacity of 2.7 newtons/cm •' gave best agreement with the observations. Static firing of the vernier engines against the surface moved surface particles; a crater 20 cm in diameter and about 1 cm deep was produced, apparently at engine shutdown. The permeability of the soil to gases, to a depth of about 25 cm, is 1 X 10 -s cm .ø,

The Roman military presence at Dalswinton is reassessed using a range of remote sensing techniques (geophysical survey, LiDAR and aerial photography). At Bankfoot the absence of internal buildings suggests the postulated vexillation fortress was a more temporary structure; while numerous pits/ovens were identified across the interior of the large Stracathro-type camp. The primary fort at Bankhead was provided with in-turned entrances and two small annexes attached to the north-west and south-east quadrants of the fort. A third much larger annexe extended southwards down to the river. Only pits and furnaces were recorded within the annexes, two of which were expanded in Phase 2. Various buildings, including legionary and auxiliary barracks, were identified in the expanded fort of Phase 2, whose orientation remained unchanged. A mixed garrison of legionaries and auxiliary cavalry is indicated for both periods of occupation. Finally, the fort was deliberately demolished. The Roman attribution of the three nearby enclosures at Butterhole Brae can no longer be supported.