Gabbro

Gabbro is a Hearthian astronaut located at their camp on an island on Giant's Deep. They found multiple Nomai Statues and brought the statue the player character pairs with to the observatory on Timber Hearth. They accidentally pair to one during the same loop as the player character, meaning they both experience the time loops but only remember starting at time loop 9354. They play the flute/clarinet (It sounds like a clarinet to me.)

Gabbro is friendly towards the protagonist and displays a very casual, laid-back attitude, although based on their knowledge about quantum mechanics and their musings about the time loop, they seem to be a competent and clever astronaut.

Selecting their dialogue option "How do you stay so calm in the face of repeated impending death?", which is unlocked on the third loop, teaches the protagonist how to meditate to end the current loop early and adds the meditation option in the pause menu. This will be very beneficial for almost the whole game

Important Notes/Dialogue
Gabbro recommends that you go to Statue Island, he tells you it's a Island "mostly" connected by two natural rock arches

Gabbro gives you a pointer towards the Orbital Probe Cannon as he tells you he saw a bright flash in the sky