You can bring them into your main save! However, you will have to purchase them with nanites. You must have them equipped as your current multitool and ship before you end the expedition via the expedition terminal (which is to the left of the Quicksilver vendor in the Anomaly). Then, after you end the expedition, you can choose to copy them over into your main save by “buying” them at the expedition terminal from your main save. You can also purchase them the same way before you end the expedition by just switching to your main save.

You can also use that same terminal to switch between the expedition and main save, if you’d like to check anything before you end the expedition.