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 Chinese as a foreign language Chinese as a foreign or second language is the study of the Chinese varieties by non-native speakers. Increased interest in China from those outside has led to a corresponding interest in the study of Standard Chinese ("Mandarin") as a foreign language, the official language of mainland China and Taiwan. However, the teaching of Chinese both within and outside China is not a recent phenomenon. Westerners began learning different Chinese varieties in the 16th century. Within China, Mandarin became the official language in the early 20th century. Mandarin also became the official language of Taiwan when