DragonFly is a prototype low-altitude rocket-powered test article for a propulsively-landed version of the SpaceX Dragon space capsule. DragonFly is a suborbital reusable launch vehicle (RLV), intended for low-altitude flight testing.
DragonFly is expected to undergo an extensive test program to support reusable rocket technology development for a cargo-carrying and passenger-carrying shuttle capsule. The testing started in Texas at the McGregor Rocket Test Facility in October 2015, although it was originally expected to start in 2014.
In May 2014, SpaceX publicly announced an extensive test program for a propulsively-landed space capsule called DragonFly. The tests was to be run in Texas at the McGregor Rocket Test Facility in 2014–2015.
A Final Environmental Assessment was issued by the FAA in August 2014. The FAA determined that the DragonFly test program „would not significantly impact the quality of the human environment.“ The assessment estimated that the program would take two years for SpaceX to complete and considered a total of 30 annual operations of the DragonFly test vehicle in each year of operation. The permit must be renewed with the FAA to continue to test the spacecraft.
SpaceX received a renewal permit from the FAA on July 29, 2016 to continue another year of flight testing.
The DragonFly test vehicle is powered by eight SuperDraco hypergolic rocket engines, arranged in a redundant pattern to support fault-tolerance in the propulsion system design. SuperDracos use a storable propellant combination of monomethyl hydrazine (MMH) fuel and nitrogen tetroxide oxidizer (NTO), the same propellants used in the much smaller Draco thrusters used for attitude control and maneuvering on the first-generation Dragon spacecraft. While SuperDraco engines are capable of 73,000 newtons (16,400 lbf) of thrust, during use on DragonFly flight test vehicle each will be throttled to less than 68,170 newtons (15,325 lbf) to maintain vehicle stability.
A flight test program of up to 60 flights has been proposed. An outline for thirty of those flights includes two propulsive assist (parachutes plus thrusters) and two propulsive landing (no parachutes) landing-only test flights where DragonFly will be dropped from a helicopter at an altitude of approximately 3,000 meters (10,000 ft). The other 26 test flights are projected to be vertical takeoff, vertical landing (VTVL) test flights that will take off from a purpose-built pad: eight to be propulsive assist hops (landing with parachutes plus thrusters) and 18 to be full propulsive hops where the landing is made with only rocket propulsion, similar to the Grasshopper and F9R Dev booster stage test flights that SpaceX also flies out of their McGregor facility.
Test flights will include a subset of tests that will test both the DragonFly space capsule and the attached trunk, an unpressurized structure that typically carries mission-specific cargo and houses the power supply system for Dragon orbital flights. The others will test landing only the capsule itself without the trunk.
The DragonFly test vehicle—formerly the Dragon2 test article that was used in the May 2015 pad abort test—was at McGregor for the start of the two-year test program by October 2015.