I suspect most meshes will be broken into several layers - Public layer, where anything can connects. This is like the public internet. Private layer, which has protected data and limited access. This is like private web sites and networks, protected by firewalls and other basic controls (and can normally be hacked remotely). Secured network, which is like a private layer, but has much better controls, including some which may not be crackable by normal means (for instance, QE networks). Segregated networks, which are disconnected from the mesh, or have only limited connectivity. These are the most difficult for most crackers to attack. The more critical the system, the lower on that scale it will be. I imagine a ship will have all of these layers, but the ship's guidance AI will be on a segregated network supported by dedicated connections, to reduce the risk of viral infection and so on. A possible network layout would have the sensors feed through a DMZ (Demilitarized zone, a firewalled server with very high security and limited connectivity) to the guidance network. The sensors would also have a one-way feed to the general ship systems, so the general public can get data from the sensors, but they can't send data to the sensors and up to the guidance systems. There are two communications systems, one on the public level, and one connected via DMZ to the guidance AI. Send and receive are possibly delinked, to reduce vulnerability to attack, and they only accept connections to known agents (so a random hacker can't connect to the security comm links and attack that way). At least, that's how I'd lay out a "good" ship. An average ship is probably much simpler (and much more vulnerable to attack, with only a few select systems running on segregated or hardware-only systems, such as the generator and engines). Once you have access to the AI, you have to overcome its security. Good ship AI is going to be worth a lot, and copying it creates security vulnerabilities, so it will resist copying. This may use things like encryption, copy protection, critical pieces encoded solely in hardware, or other ingenius schemes. If you have access to the security network and the appropriate skills, you should be able to rip a copy, given time. Otherwise it would take a pretty fantastic test to get the bulk of the AI (if it's possible at all), and you'll have to repair it later, if it's possible. The mesh is called the mesh because it automatically interlinks (unless intentionally segregated). So your ship's public mesh and the planetary public mesh will interconnect if within range. Once you leave range, they separate. Segregated meshes will never connect, so no difference. Parts of the ship's AI may be turned off, for instance communications. Most functions that are vulnerable to hacking will rarely be turned on (like the control panel or maintenance access). But for the most part, if a part of the AI is critical enough to be part of the guidance AI and on the segregated network, it's probably there for a reason, and its state won't change much between orbit and deep space.