White sands. Views of White Sands, New Mexico, USA. At right is an orbital view from EO-1 showing White Sands and vicinity. The Alkali Flats area and Lake Lucero are the sources of the white sand. Both are paved with selenite crystals (upper-left and left) — evaporitic remains of Pleistocene Lake Otero. The gypsum blows ENE with the prevailing winds to produce dunes downwind from the lakebed (lower-left), which take on barchan, barchanoid, transverse, and dome dune forms. Space Shuttle Columbia landed on the airstrip at the northwest end of the alkali flats (White Sands Space Harbor) on 1982 March 30 due to inclement weather at Edwards Air Force Base.