Orion is a series of American

solid-fuel rocket A solid-propellant rocket or solid rocket is a rocket with a rocket engine that uses Rocket propellant#Solid chemical propellants, solid propellants (fuel/oxidizer). The earliest rockets were solid-fuel rockets powered by gunpowder. The incepti ...

stages, developed and manufactured by a joint venture between Hercules Aerospace and

Alliant Techsystems Alliant Techsystems Inc. (ATK) was an American Aerospace manufacturer, aerospace and arms industry, arms manufacturer headquartered in Arlington County, Virginia. The company operated across 22 states, Puerto Rico, and internationally. ATK reven ...

(now

Northrop Grumman Innovation Systems Orbital ATK Inc. was an American aerospace manufacturer and defense industry company. It was formed in February 9, 2015 from the merger of Orbital Sciences Corporation and parts of Alliant Techsystems (ATK). Orbital ATK designed, built, and deli ...

). They were originally developed for use as all three stages on the

Pegasus rocket Pegasus is an Air launch to orbit, air-launched launch vehicle, multistage rocket developed by Orbital Sciences Corporation (OSC) and later built and launched by Northrop Grumman. Pegasus is the world's first privately developed orbital laun ...

, first flown in 1990. Orion is available in several configurations for a variety of use scenarios. All stages in this family use an ammonium perchlorate composite propellant called QDL-1, which includes

HTPB Hydroxyl-terminated polybutadiene (HTPB) is an oligomer of butadiene terminated at each end with a hydroxyl functional group. It reacts with isocyanates to form polyurethane polymers. HTPB is a translucent liquid with a color similar to wax paper ...

binder and 19%

aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

, with the exception of the yet-unflown Orion 32, which uses QDL-2, containing HTPB binder and 20% aluminium.

Versions

Orion stages are numbered to indicate their configuration. The first number, either 38 or 50, indicates the diameter of the stage. This is followed by various letters. S indicates a stretched, first stage variant. XL indicates an additional stretch. G indicates a ground-launched stage, with a shorter nozzle. T indicates a strengthened skirt.

References

{{Rocket engines Alliant Techsystems Spaceflight Solid-fuel rockets