But an AGI wouldn't be an AGI if it wasn't able to figure out how to solve the problem of getting from here to there and using in-situ resources to replicate itself.
It remains to be seen whether we humans can do that. Does this mean we might not be general intelligences, either? That seems like a slightly silly and very nonstandard way to use the term.
Eh... read up on the literature. Pay special attention to studies done by the British Interplanetary Society and the Advanced Automation in Space NASA workshop in the 80's, not to mention all the work done by early space advocates, some published, some not.
We can say with some confidence that we know how to do something even if it hasn't yet been reduced to practice or yet practially demonstrated. 19th century thinkers showed how rockets could in principle be built to enable human exploration of space. And they were right, pretty much on every point -- we ...
An Article on Motherboard reports about Alien Minds by Susan Schneider who claiThe Dominant Life Form In the Cosmos Is Probably Superintelligent Robots. The article is crosslinked to other posts about superintelligence and at the end discusses the question why these alien robots leave us along. The arguments puts forth on this don't convince me though.