Chief Engineer

Ships can be modified at the technician who is in the landing area in every major city; including Jemison where you start, and Akila which is well worth heading to in short order. They are always either standing between your ship and the way to the city, or in a small hut/building nearby.

All you need to do is make any change to your ship and it'll pop.

No need to hurry though - can be done at any time and you'll want to make upgrades soon enough... ...once you've got enough credits.