The release of the doors, and thus the deployment of the satellites, is performed by the ball-lock  mechanism. The ball-lock is located between the two doors on one side of the door frame assembly (as to  not interfere with the satellite deployment). All ball-lock components are contained inside a housing, which  is fastened to the door frame assembly. When in the stowed (doors closed) position, the ball-lock functions  by extending and holding precision ball bearings into receptacles in each of the doors. Release is performed  by the retraction of the central plunger via pin puller, which allows the ball bearings to slide down a ramp  geometry and retract into the housing. Retraction of the ball bearings from the receptacles allows the doors  to swing freely and release the satellites.  On-Orbit Anomaly  The Orb-1 missions of the NRCSD experienced a deployment anomaly on-orbit that was diagnosed,  troubleshot, and overcome in real-time, resulting in the successful deployment of all satellites. The anomaly,  which was determined to be electronic, was due to the cold temperature of the NRCSD system at time of  deployment. Basically, the electronics did not function in the cold temperature extreme, and deployment  was planned just as the ISS was coming out of eclipse. The problem was mitigated by turning on the Launch  Command Multiplexer (LCM1) for a number of hours prior to deployment, which allowed the internal  components to come to operating temperature and function correctly. The LCM was returned to Earth for  diagnosis, and a newly-designed LCM (LCM2) was flown for the Orb-2 mission.  On Thursday, September 14, 2014 (GMT 247), the last round of commands was sent to the Orb-2 mission  of the NRCSD. Four (4) deployers had deployed nominally, two (2) had not deployed. Two (2) had deployed  hours after they had been commanded. A series of real-time safety meetings were held to determine a path  forward. Of notable concern was the fact that two deployers had released at an undetermined time after  being commanded, and that the two remaining un-deployed deployers had also been previously  commanded. This was a concern because the NRCSD needed to be returned to the JEM airlock and  brought inside; many options were considered, but ultimately a number of decisions were made. First, a  translation path was determined that minimized the amount of safety-critical hardware in the line of  deployment (should the deployment inadvertently occur during translation). Next, the safety-critical  hardware components were analyzed for structural safety should they be impacted by a deployed satellite.  Measures were taken to protect the ISS components that were identified as being at risk (specifically, the  observation window in the JEM airlock was protected). Finally, a procedure was implemented for the  protection of the astronauts once the NRCSD was returned inside the ISS pressurized volume. The plan  was executed, and the NRCSD was returned and placed in a safe configuration without incident.  Anomaly Investigation  Aspects of the anomaly investigation occurred immediately upon discovery of the failure to deploy. Crew  photography revealed that the first deployer that had inadvertently deployed after command had a slightly  retracted ball-lock plunger (Figure 2). This exact signature was observed in one of the three remaining  deployers that had failed to deploy. Scrutiny was applied to the electronics/avionics systems – this system  as well as the associated cabling was photographed and observed during disassembly and analyzed on  the ground. Finally, a Fault Tree Analysis was started and ground investigations began in earnest.   NASA/CP—2018-219887 353