Interorbital Marks Major Milestone with Rocket Engine Firing

MOJAVE — On a calm clear high-desert October evening, Interorbital Systems’ NEPTUNE rocket series’ main engine roared to life in its first hot-firing test. The engine, the IOS GPRE 7.5KNTA (General Purpose Rocket Engine; 7,500lb-thrust; Nitric Acid; Turpentine; Ablative cooling), blasted a 22-foot (6.71-meter) plume of fire across Interorbital’s Mojave Spaceport test area, scorching the sand an additional 50 feet (15.24 meters) beyond the plume end.

The all-composite chambered 7.5K-pound (33,362-newton) thrust engine is the largest rocket engine in the world utilizing high-density, storable nitric acid and turpentine. These hypergolic propellants provide almost instantaneous chemical ignition. This static firing marks a major milestone in the evolution of the company’s NEPTUNE Modular Orbital Launch Vehicle series.

GPRE 7.5KNTA Main Rocket Engine Test (October 28, 2012). Luminous desert sand vortices reflect the extreme brilliance of the rocket plume.

Refining the engine operation paves the way for the first flight test  of the CPM—Common Propulsion Module—the stand-alone rocket that is the primary construction element of various bundled configurations that yield launch vehicles specially designed to meet specific mission requirements. IOS’ first orbital launcher is a seven-module rocket designated the NEPTUNE 7 (N7)—powered by seven of the GPRE 7.5KNTA engines—and purposed to lift a mixed-manifest of some 24 TubeSats and CubeSats on each launch. Interorbital recently completed a NASA Phase I SBIR contract, awarded to further the development of the NEPTUNE Modular Rocket series.