First posted July 20, 2023 For additional information, contact: Director,California Water Science CenterU.S. Geological Survey6000 J Street, Placer HallSacramento, California 95819 Quaternary marine and continental shales in the western United States are sources of selenium that can be loaded into aquatic environment through mining, agricultural, energy production processes. The mobilization fr...

manned lunar landing problem. Landing hazards exist everywhere on the Moon, and many of the more desirable landing sites are near the most hazardous terrain, so HDA is needed to autonomously and safely land payloads over much of the lunar surface. The HDA requirements used in the ALHAT project are to detect hazards that are 0.3 m tall or higher and slopes that are 5° or greater. Steep slopes, r...