d.  Special support components for optical sensors, as follows:

     d.1.  "Space-qualified" cryocoolers;

     d.2. Non-"space-qualified" cryocoolers, having a cooling source temperature below 218 K (-55øC), as follows:

          d.2.a.  Closed cycle type with a specified Mean-Time-To-Failure (MTTF), 
                  or Mean-Time-Between-Failures (MTBF), exceeding 2,500 hours;

          d.2.b.  Joule-Thomson (JT) self-regulating minicoolers having bore (outside) 
                  diameters of less than 8 mm;

     d.3.  Optical sensing fibers specially fabricated either compositionally or structurally, 
           or modified by coating, to be acoustically, thermally, inertially, electromagnetically 
           or nuclear radiation sensitive.