Hardspace: Shipbreaker

Suit patch up kits can be obtained as salvage on some ships, but can be purchased at the shop terminal in the shipbreaking area (just to the left when you exit your habitat).

In order to use one your suit must be damaged. This can be achieved by using your handheld utility grapple's pull function to build up some speed and slam yourself into far away objects, or by waiting to naturally take damage during the course of gameplay.