302   The following is a quick summary of the system capabilities:   Torque:  56.5 – 113 N -m (500 – 1000 in- lb)  Unlatch ed Unpowered Holding Torque: 9 – 33.9 N -m (80 – 300 in- lb)  Latch Unpowered Holding torque: 171.2 N -m (1515 in- lb) [no movement ]  Latch Unpowered Holding torque:  >384.1 N -m (>3400 in- lb) [slight movement, no damage]   Stiffness: 169,477 N -m/rad min ( 1,500,000 in- lb/rad min)  [at 384.1 N-m (1515 in- lb)]   The Deployment and Positioning System containing the Deployment and Latching Mechanism has  completed protoqual  testing and is in final integration, scheduled for launch in fall 2016.    Although the deployment and latching mechanism used a deployment actuator and a latching actuator, the mechanism is scalable. The NICER requirements dictated the sizes of the actuators used. Depending on  the stiffness required and the torque required at the deployment actuator, the deployment actuator can be scaled up or down. The latching actuator is sized based on the load required in the bolt, the over-center   load that is reacted b y the actuator and the load the slider crank has to react  to. The NICER deployment  and latching mechanism is arranged in a vertical configuration with the latching actuator on the bottom .  Depending on the available envelope, the latching actuator can be positioned anywhere radially around the deployment actuator . If envelope is available, a horizontal configuration would allow for a lower vertical  profile  and increased stiffness . 

Future W ork / Optional Designs  

Add i ntermediate latching positions with some loss of stiffness   Intermediate positions can be added. Hysteresis caused by change in torque direction would result in a  loss of stiffness between the initial torque direction and the second torque direction.  

Develop a t wo-slider design for intermediate positions with no loss of stiffness   The addition of a second slider independent of the first , contained in the same slider block, can be used to  latch the deployment actuator at intermediate positions . The second independent slider will resist  loading  in the opposite direction. Clearance on the back side of each slider and shimming on the deployment  actuator , will ensure loading in both directions . The loading in both directions will result in the elimination of  system hysteresis and result in similar torsional stiffness in both directions.  

Develop a t wo-slider design to enable ≥360° output rotation (no hardstops needed)   The addition of the second slider, as described above, can also allow the deployment actuator to rotate more than 360° or if continuous rotation is required and to be latched in multiple predetermined positions.  

Acknowledg ments  

With the NICER DAPS program being a “collaborative effort between NASA’s Goddard Space Flight Center (GSFC) and Moog Inc.”  2, the authors of this paper  would like to extend a special  thank  you to  Keith  Gend reau, Zaven Arzoumanian, Charles Baker , Kuo -Chiu (Alice) Liu, and Alissa Mitchell and all of the  NICER team at the NASA Goddard Space Flight Center for the opportunity to participate in this challengin g  and exciting program . Additionally, the authors of this paper would like to extend a special thanks to the  entire Moog NICER program team, without them this system could not have been built.  

References   1 NASA Website, https://heasarc.gsfc.nasa.gov/docs/nicer/   2 Paraphrased from NASA GSFC Pointing, Deployment, and Latching Mechanism Hardware Assembly     Performance Requirements Specification EXP -NICER- MECHM -SPEC -0016