its about studying to be a astronaut. one scene is where they were grouped into 3 and 2 of them needs to move blocks while 1 of them stays above to instruct them, one of the ones below realized what they were building which is the Apollo space ship and started to move on his own. THANK YOU! 🙂

Is it Space Brothers? That's the only astronaut manga I know so can't provide more titles.

Nulla in mundo pax sincera
"Always go too far, because that's where you'll find the truth." - Albert Camus

I believe it's St&rs.

Thank you for replying 🙂 but its not space brothers because the characters are teenagers. I remember that there is this bratty blonde girl that hates the protagonist but eventually had a crush on him.

@empressasuka Thank you but nope, its not. 🙁

Futatsu no Spica?

Thank you for your reply but no. The protagonist is male. 🙄

It is St&rs. Please read chapter 3.

Owner of Antisense Scanslation.

No, because the manga I'm talking about has anime. And I watched the anime too like 7-8 years ago.