Interorbital successfully test fires its CPM vernier rocket engine!  Two of these small vernier rocket engines provide roll control for a stand-alone Common Propulsion Module (CPM) stage. CPMs are the basic building blocks for IOS' multi-stage bundled modular rockets--as in the NEPTUNE 5 (N5), a five-module orbital rocket. IOS rocket engines are the first US rocket engines utilizing storable high-density nitric acid and turpentine as propellants. In addition to the vernier rocket engine, the series of tests included the verification of the CPM controller. This unit is the interface between the CPM and the user or the guidance software. The test series also verified IOS' rocket launch control software developed to control the launch of the NEPTUNE series rockets. This software allows the use of a laptop computer or tablet computer for simple low-cost launch control. Launch crew training and key ground support equipment were also verified in this series of tests. These field trials were precursors to the 7,000-lb-thrust CPM main engine hot-firings, which will begin soon at the IOS test facilities, located at the Mojave Air and Space Port.