The Neutral Buoyancy risk abatement test was conducted at the Marshall Space Flight Center (MSFC) Neutral Buoyancy Simulator facility during June and July 1995. The purpose of this neutral buoyancy simulation was to evaluate the crew interfaces associated with intra-vehicular activity (IVA) and extravehicular activity (EVA) operations for the International Space Station (ISS) Product Group-3 (PG-3) hardware.There were seven test objectives evaluated during the 1995 NBS test; three EVA and four IVA. The IVA tasks included two Carbon Dioxide Removal Assembly (CDRA) maintenance evaluations, a Fluid System Servicer (FSS) operation evaluation and an Active Rack Isolation System (ARIS) rack installation/removal demonstration. The two CDRA maintenance tasks were removal and replacement of the upper rear heater controller Orbital Replaceable Unit (ORU) and removal and replacement of the rear Desiccant/Adsorbent (D/A) bed ORU. This paper will report on the results of IVA tests involving the CDRA rear D/A bed ORU removal and replacement test.