Chief of the Astronaut Office procedures, and selection and conduct of specific experiments for each flight. Since the Shuttle era, the Chief of the Astronaut Office often returns to active duty in the Office once their term is complete. The Chief is currently responsible for managing Astronaut Office resources and operations, and helps develop astronaut flight crew operation concepts and crew assignments for future spaceflight missions. Chief of the Astronaut Office The Chief of the Astronaut Office is the most senior leadership position for active astronauts at the National Aeronautics and Space Administration (NASA). The Chief Astronaut serves as head of the NASA Astronaut Corps
Chinese as a foreign language neutral (轻声，denoted as no-mark in Pinyin) although the official name of the tones is Four Tones. Many other Chinese dialects have more, for example, Cantonese has six (often numbered as nine, but three are duplicates). In most Western languages, tones are only used to express emphasis or emotion, not to distinguish meanings as in Chinese. A French Jesuit, in a letter, relates how the Chinese tones cause a problem for understanding: Moser also stated that tones were a contributing factor to the difficulty of learning Chinese, partly because it is difficult for non-native learners to know how to convey emotion