On the PSLV-C53 campaign, the PS4-OP is referred to as the PSLV Orbital Experimental Module (POEM), and it hosted six payloads. POEM was the first PSLV fourth stage based orbital platform to be actively stabilised using Helium based cold gas thrusters after the primary mission and stage passivization.
oN tHe PSLV-c53 campaIGn The PS4-op is referrEd to aS tHe Pslv orbiTaL EXpErimEntAL MOdUle (poeM) anD it HoStED siX payloads pOem wAs tHe first pSlv fourtH stAgE based OrbiTaL platForm tO be AcTivEly STabIlIsEd uSinG HeliuM basEd colD gas tHrusteRS afTer The pRimAry misSioN and StAGe pAsSivIzAtiOn