So Reva can answer (this is all general information assuming an easy Engineering check):<br/><br/>The force fields are probably maintained by a series of small portable devices, unless the ship had anything built in that the squatters reactivated.  They are likely networked together in some fashion, potentially by wire unless each one has an individual battery.  If networked by wire direct access (or I think there are a few explicit wireless hack methods) would be required to hack.  Hacking them, wirelessly or wiredly (is that a word?), would likely be more of an event as the network is likely (more) actively monitored and would potentially have countermeasures.  It wouldn't just be decoding a signal like last time, it would be an active hack against someone who might notice.