W.L. Quaide V.R. Oberbeck H. J. Moore D. E. Gault 1966 The morphological features of the lunar surface photographed by Luna 9 indicate a surficial layer of weakly cohesive to noncohesive fragmental material. Most of this material is finer than a centimeter and probably finer than a few millimeters, although objects of centimeter size and larger are plentiful. application/pdf 10.1126/science.153.3739.985 en American Association for the Advancement of Science Luna 9 photographs: Evidence for a fragmental surface layer article