This was also eye-opening to me. I was not aware NOVA was on PSP.
It was ported as a PS Mini title. The port was handled in-house by Gameloft, so it's a decent port, though a bit slower due to the not-shooter-centric hardware; it rises above the challenge by slightly rebalancing the AI to account for slower or less-precise player input. Bank on that too much though, and you'll still get thrashed. It makes you play harder with no scapegoats.
I hope that NOVA 2 and 3 make it to Vita myself, along with Dead Space iOS.