It's kinda hidden. Go to where the portal is like you're going to go to your base instead of flying your ship back out, then while facing the portal, turn left. Tucked in the corner is a place to scrap multi-tools.

Most of them give you regular currency, some you get the motes (I think that's what they're called?) that are Autophage currency. I think the multi-tools added in Echoes give you the mote currency when you scrap them.

With some practice, I can come in on my ship, then jetpack through the window and be on top of the multi-tool scrapper place without having to run up the ramp. Similar to how you can jetpack up to Nada and Polo.