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 language proficiency exam program, which tests has been taken around 100 million times (including by domestic ethnic minority candidates). Within China's Guangdong Province, Cantonese is also offered in some schools as optional or extra-curricular courses in select Chinese as a foreign language programs, although many require students to be proficient in the Mandarin first. Chinese is rated as one of the most difficult languages to learn for people whose native language is English, together with Arabic, Japanese and Korean. According to the Foreign Service Institute, a native English speaker needs over 2,200 hours of intensive study, taking 88 weeks