The APEX satellite, also known by its NORAD ID 23191 and OBJECT_ID 1994-046A, was launched on August 3, 1994, from the AFWTR launch site using a Pegasus launch vehicle. Built by OSCG for STP, this satellite is categorized under the PegaStar configuration with a mission focus on technology. It measures 2.5 meters in length and has a diameter of 1.2 meters, with a span of 4.3 meters. The APEX carries equipment such as PASP-Plus, CRUX, and FERRO, weighs 261 kilograms at launch and dry mass, and is powered by four deployable fixed solar arrays along with batteries. Its shape is described as Hex Cyl + 4 Pan, and it has an RCS of 2.2542. The APEX satellite operated for a lifetime of 7 years.