SuperDraco (Dragon Abort)

SuperDraco is the rocket engine that gets astronauts away from danger in a hurry. SpaceX built eight of them into the Crew Dragon spacecraft so the capsule can shove itself clear of a failing rocket in a fraction of a second.

Quick facts

• Maker and use: Built by SpaceX to power the launch escape (abort) system of the Crew Dragon spacecraft, also called Dragon 2.
• Count and layout: Eight engines mounted in four pods of two around the sides of the capsule.
• Thrust: About 71 kilonewtons (roughly 16,000 pounds of force) per engine at sea level, for a combined total of about 568 kilonewtons.
• Propellants: A hypergolic mix of monomethylhydrazine (MMH) fuel and dinitrogen tetroxide (N2O4) oxidizer.
• Throttle range: 20% to 100% of full thrust.
• Speed to full power: About 100 milliseconds (a tenth of a second) from ignition to full thrust.
• Other numbers: Chamber pressure about 6.9 megapascals (1,000 psi); specific impulse about 235 seconds at sea level; capsule propellant load about 1,388 kilograms (3,060 pounds).
• Firsts: The first fully 3D-printed (additively manufactured) rocket engine to fly.

What it is and how it works

SuperDraco runs on hypergolic propellants, which means the two liquids catch fire the instant they touch. That removes the need for a spark plug or igniter and lets the engines light almost instantly. The propellants are pressure-fed (pushed by gas pressure rather than pumps) and storable at room temperature, so the system can sit fueled and ready for long stretches of time without special chilling.

The eight engines are grouped in four pods around the capsule’s hull. If the onboard computers or launch control detect a failure, all eight fire together and burn for several seconds, accelerating the capsule off the rocket at high g-loads (forces several times the pull of gravity). Think of it like an ejection seat for a whole crew cabin, except it pushes the cabin away rather than punching the people through the roof.

SuperDraco can also throttle deeply (down to 20%) and restart. That is why SpaceX originally planned to use it for propulsive landings, lowering the capsule to the ground on rocket power. That plan was later dropped in favor of parachute splashdowns, with SuperDraco kept as an emergency backup. Each engine is roughly 200 times more powerful than the smaller Draco thruster used for steering the capsule in space.

Why it matters

SuperDraco is the heart of Crew Dragon’s safety design and a key reason NASA certified the vehicle to carry astronauts under the Commercial Crew Program. Older capsules such as Mercury, Apollo, Soyuz, and Orion use a solid-fueled escape tower, a small rocket on a tower that pulls the capsule away early in flight and is then thrown away. That leaves a gap with no powered escape for the rest of the climb to orbit.

Because SuperDraco is built permanently into the spacecraft instead of bolted to a disposable tower, Crew Dragon keeps a powered escape option through every phase of ascent, all the way to orbit. The trade-off is dead weight that flies to orbit on every mission, but it buys full-ascent abort coverage. The engine also advanced rocketry: its combustion chamber is 3D-printed from Inconel, a tough nickel superalloy, using direct metal laser sintering. That made complex cooling passages and injector shapes possible and shortened production time.

Where it is used and notable examples

• Crew Dragon (Dragon 2): Carries the eight SuperDraco engines as its integrated escape system. SpaceX announced the SuperDraco engine on February 1, 2012, and announced that the engine had completed qualification testing on May 27, 2014.
• Pad Abort Test (May 6, 2015): All eight engines fired for several seconds at Cape Canaveral, lifting an uncrewed capsule off a test stand to prove a ground-level abort.
• April 20, 2019 anomaly: Capsule C204 was destroyed during a static fire test when a leaking check valve let oxidizer enter the helium pressurization line. The fix replaced the check valves with burst disks.
• In-Flight Abort Test (January 19, 2020): The capsule aborted at supersonic speed during the booster’s hardest aerodynamic moment, proving a high-stress in-flight escape; the booster was intentionally destroyed.
• Crewed missions: Starting with Demo-2 in 2020 and later NASA and commercial flights, Crew Dragon flies with SuperDraco armed as the active abort system and a parachute backup.