According to the person in this NPR piece (who was on it last year) there are a variety of fairly inexpensive off-the-shelf things used, including the LED light

According to the person in this NPR piece (who was on it last year) there are a variety of fairly inexpensive off-the-shelf things used, including the LED lighting. https://www.npr.org/2023/06/20/1183273102/titan-missing-sub-titanic-rescue-oceangate https://www.npr.org/2023/06/20/1183273102/titan-missing-sub-... Also relevant (and discussed in the piece) there are multiple independent systems to increase buoyancy and bring it back up to the surface, including some that should trigger automatically even if everyone aboard is unconscious. Not discussed was whether any of them would operate if it lost pressure containment.