Hi teachers.<br/><br/>I wonder if this sentence is grammatically correct or not.<br/><br/>If NASA <u>sends</u> astronauts on that new mission to the Moon, it <u>will have done</u> so for the first time since 1972.<br/><br/>Underlined parts confused me a lot. I also think "since" requires present perfect, doesn't it? <br/><br/>Thank you.