Atmosphere of Earth the border between the atmosphere and outer space. Atmospheric effects become noticeable during atmospheric reentry of spacecraft at an altitude of around . Several layers can be distinguished in the atmosphere, based on characteristics such as temperature and composition. The study of Earth's atmosphere and its processes is called atmospheric science (aerology). Early pioneers in the field include Léon Teisserenc de Bort and Richard Assmann. The three major constituents of Earth's atmosphere are nitrogen, oxygen, and argon. Water vapor accounts for roughly 0.25% of the atmosphere by mass. The concentration of water vapor (a greenhouse gas) varies significantly from around
NRIST S-80 series UAV NRIST S-80 series UAV NRIST S-80 series UAVs are Chinese UAVs developed by Nanjing Research Institute of Simulation Technology (南京模拟技术研究所) (NRIST), also known as the 60th Research Institute of People's Liberation Army General Staff Department (总参六十所), an ISO 9001 certified research/production facility headquartered in Nanjing. S-80 series UAVs are part of larger NRIST S-series UAVs. S-80 drone is a fixed wing UAV developed by NRIST, and it is a development of earlier NRIST B-9H drone. Like its predecessor B-9H, S-80 is also developed for naval use on board ships. S-80 drone is constructed of fiber glass reinforced plastic with aluminum