Translation guide
NASA is the U.S. space agency. In Japanese, it is almost always referred to by its acronym, pronounced in a Japanized way. There is no common Japanese translation; the acronym is used directly.
Referring to the National Aeronautics and Space Administration
The acronym is used as-is in Japanese, written in Latin letters or occasionally in katakana. It is universally understood.
NASAはアメリカの宇宙機関です。
NASA is the American space agency.
NASAの最新のミッションについて聞きましたか？
Did you hear about NASA's latest mission?
Katakana rendering of NASA, sometimes used in Japanese text, but the Latin alphabet version is more common.
ナサの宇宙飛行士が講演しました。
A NASA astronaut gave a lecture.
The official Japanese translation of NASA's full name. It is rarely used in conversation; mostly seen in formal documents or news.
アメリカ航空宇宙局（NASA）は新たな探査計画を発表した。
The National Aeronautics and Space Administration (NASA) announced a new exploration plan.