Astronaut training engineers, technicians, pilots, and geologists. In addition there will be a focus on the psychological aspects of long-duration missions where crew is largely isolated. Currently a six-month mission to the ISS requires up to five years of astronaut training. This level of training is to be expected and likely to be expanded upon for future space exploration missions. It may also include in-flight training aspects. It may be possible that the ISS will be used as a long-duration astronaut training facility in the future. A powerful tool for astronaut training will be the continuing use of analog environments, including NASA
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