The creator of the flag is unknown. The meaning of the stripes' colors are as follows: Dark blue for night time, light gray for the color of the moon, pink for femininity, yellow for the color of the sun, and lastly blue for the color of the sky during daytime. Additionally, the star polygon stands for the prefix "astro-", whereas the royal blue color stands for masculinity.
The term "astrogender" is a composition of astro- (meaning star) and gender, since it's a gender identity that constantly changes depending on the current configuration of the night sky.
The term was originally coined by Tumblr user arco-pluris on August 18, 2018. It was defined as "an amplusgender (fluid/flux/liquid) for when gender spectrum is seen from a galactic perspective; feeling like an astronaut navigating through potential genders that could be inhabited or not." It was also mentioned by the-mogai-archive as a masculine version of astralgender on or before June 25, 2015.