This Report and Order modifies rules for operation of the Ancillary Terrestrial Component of the sole Mobile-Satellite Service system operating in the Big LEO S-band (2483.5-2495 MHz).. (Dkt No. 13-213 RM-11685 ). Action by: the Commission. Adopted: 12/22/2016 by R&O. (FCC No. 16-181).