This is the 7972nd most frequent Polish word.
nasa
The Polish word "nasa" means "our" in English.
(Nasza) Here, 'nasza' functions as a possessive adjective indicating ownership (of female gender, singular form) referring to 'friend'.
Nasza przyjaciółka właśnie wróciła z wakacji.
Our friend has just returned from vacation.
(Nasa) In this sentence, 'Nasa' is a proper noun, referring to the space agency in the United States, and is unchanged in Polish due to its proper noun status.
Nasa także wysłała rakietę na Marsa.
NASA also launched a rocket to Mars.
(Nasa) The word 'nasa' in this sentence is part of a possessive construct describing 'group' (female gender, singular form, accusative case).