okay, how I imagine this AU even came to be:
Robin and Al-an have left 4546B, but something went wrong with the phase gate. It’s over 1000 years old without any regular upkeep, of course it’s bound to have problems.
so, it ends up sending them either to another universe, or far into the past before humans expanded past earth.
At this point in time Grace and Rocky are on their way to Erid, boredom quickly setting in, but they suddenly get a loud radio signal from a nearby ship, neither of them even knowing the Hail Mary had a live radio or that there was anyone out here
Robin and Al-an have been searching for any sign of civilization, but they can’t find any space stations or phase gates, from either humans or architects. So they stop for directions!
Grace and Rocky obviously have no idea wtf they’re talking about over the radio, because what’s normal to Robin is just futuristic sci-fi jargon to them.
Realizing they don’t have directions, Robin takes a leap of faith and asks if they have any food. It feels super rude, but she didn’t pack any because the phase gate trip would’ve only taken a few minutes, and now she’s starving
long story short, they end up boarding the Hail Mary, initially worried that it might be a trap set by Alterra but quickly realizing “yeah no it’s just these two dudes we’re fine and also holy shit is this a nasa ship I thought that program got bought out like 200 years ago????”
and they agree to hitch a ride, hoping they’ll pass by a phase gate eventually (which they won’t)