Star Trek Beyond/Fridge

Fridge Brilliance

 * Despite the derelict Starfleet vessel found on the alien planet having been stranded there since roughly Captain Archer's time (even having the NX designation) and looking the part, it's still remarkably sturdy and capable of spaceflight. While it might be surprising, ships of that time had to be made tough as they didn't have shields and thus were built to last.
 * It makes sense that the technology from the Neglectful Precursors that allows Krall to both live long and siphon energy from other living beings would also be coded with alien DNA in mind, in the process making Krall's genetic makeup utterly flexible.