MOJAVE-10.28.2012—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.

Randa Relich Milliron CEO Interorbital Systems

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. 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)—a three-stage orbital vehicle powered by seven 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.

Watch GPRE 7 5KNTA Test 1E81b

Interorbital Systems http://www.interorbital.com/