Something along these lines would be fun.
I'm not the greatest designer, but I think you get the idea: a cute rocket with a rainbow trail.
A few other musings:
the rainbow trail reminds me of nyan cat, an animated version in that style might make for a nice loading screen
I looked up "rocket nyan cat" and saw this hamster with a rocket attached: https://static.wikia.nocookie.net/nyancat/images/5/58/RocketHamster.gif/revision/latest?cb=20210923233749
It would be cool if someone could do something similar with a lemming.
That reminds me of Buzz holding Woody with a rocket strapped to his back: https://static.wikia.nocookie.net/bd893090-c6dc-4d2f-96a5-9ec62637242e
It's a similar feeling, with Voyager (and other apps) picking up Apollo and trying to keep it flying.
The word Voyager makes me think of the Daft Punk piece, there's a bit in the video with an anime style star, this could make for a simpler icon theme: https://youtube.com/watch?v=CqZgd6-xQl8&t=2m29s
I think the name "Rocket" would be a cool name for an Apollo inspired app - simple and effective.
The rocket idea could be anthropomorphised (smiley cyclops) and become a character in an of itself; there was an astronaut with Apollo, there could be a rocket character with Voyager.
I looked up Wallace and Gromit's rocket, because I remember really liking the look, but I don't think it translates: https://youtube.com/watch?v=Kb0ooQKbflM&t=2m38s
Orange and Blue is a popular contrasting colour scheme though.
I like the rainbow focus in the brief and I hope to see some cool creations. I'm not precious about the rocket idea, but I hope it inspires some more creative submissions, I definitely think something other than a slight variation on the lemming motif would set this app apart from the rest.
On the other hand it comes off as virtue signaling if it’s meant to represent genital smashing. I like rainbows but they don’t always mean gays found here