Astronaut propulsion unit Astronaut propulsion unit An astronaut propulsion unit (or astronaut maneuvering unit) is used to move an astronaut relative to the spaceship during a spacewalk. The first astronaut propulsion unit was the Hand-Held Maneuvering Unit (HHMU) used on Gemini 4. The Hand-Held Maneuvering Unit was the EVA "zip" gun used by Ed White on the Gemini 4 mission in 1965. The hand-held gun held several pounds of nitrogen, and allowed limited movement around the Gemini spacecraft. It was also used by astronaut Michael Collins on the Gemini 10 mission in 1966. The United States Air Force (USAF) Astronaut Maneuvering Unit (AMU)
Chinese as a foreign language (one year and about 8 months), to learn Mandarin. A quote attributed to William Milne, Morrison's colleague, goes that learning Chinese is Several major difficulties stand out: While English uses an alphabet, Chinese uses "hanzi", or Chinese characters, as its writing system. The "Kangxi dictionary" contains 47,035 characters (). However, most of the characters contained there are archaic and obscure. The Chart of Common Characters of Modern Chinese (), promulgated in People's Republic of China, lists 2,500 common characters and 1,000 less-than-common characters, while the Chart of Generally Utilized Characters of Modern Chinese () lists 7,000 characters, including the 3,500