In this conceptual image, eight SuperDraco thrusters fire as a Dragon spacecraft enters the Martian atmosphere at supersonic speeds.
SpaceX
This week, SpaceX announced plans to land a Dragon spacecraft on Mars by 2018. This would be a monumental achievement for NASA or any other national space agency, let alone a single company, as the 6,000kg Dragon is nearly an order of magnitude larger than anything that has landed on the Red Planet before.
With the long-term goal of Mars colonization in its sights, SpaceX has been testing key technologies needed to land on Mars for years. One is supersonic retro propulsion, which Ars revealed has been tested since September 2013 on upgraded Falcon 9 missiles. Supersonic retro propulsion proved a resounding success.
But the Falcon 9 and its Merlin engines aren’t going to Mars. SpaceX will use a different type of engine, the SuperDraco thruster, to land propulsively on the red planet. Here’s how the landing will work: As the Dragon (dubbed Red Dragon) begins its descent to Mars at supersonic speeds, the spacecraft will fire eight of these thrusters into this onrushing atmosphere. To achieve this maneuver, these engines must be able to deliver both high thrust and controllable thrust.
This gallery shows the nearly decade-long development of the SuperDraco thrusters, critical to landing on Mars, and highlights some of their capabilities:
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SpaceX has been working on the SuperDraco thruster for nearly a decade. In June 2012, Elon Musk tweeted this photo and said, “Just fired up our SuperDraco escape rocket motor at full blast! Needed to carry astronauts on Dragon.”
SpaceX
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A Crew Dragon propulsive hover test shows how the engines operate in four pairs, distributed throughout the spacecraft.
SpaceX
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Another view of the propulsive hover test.
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This is a mosaic of images of a pair of SuperDraco thrusters undergoing a full test firing. Each engine is tested more than 300 times.
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In 2013, Elon Musk tweeted this photo of a SuperDraco inconel rocket chamber, with a regenerative cooling jacket, emerging from a 3D metal printer.
SpaceX
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A year later, in 2014, the company began revealing the full design with close-up and personal photos of a SuperDraco thruster pair.
SpaceX
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Four pairs of SuperDraco engines power the Crew Dragon spacecraft’s escape system.
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About a year ago, SpaceX conducted an important test to make sure its “launch abort system” would work in the event of a failure. Dragon’s capsule and trunk are shown here, for the test. Four SuperDraco thrusters are on display.
SpaceX
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This schematic shows how the path abort test should work.
SpaceX
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During a pad-break test in 2015, the eight thrusters fired simultaneously, quickly reaching maximum thrust, to lift Dragon off the pad.
SpaceX
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After half a second of vertical flight, the Dragon plunged toward the ocean and continued its controlled burn. The Dragon traveled from 0-100 mph in 1.2 seconds and reached a maximum speed of 345 mph.
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Shortly thereafter, the hull was jettisoned and the spacecraft slowly began to spin with the heat shield facing the ground.
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During the pad-abort test, the vehicle landed with a parachute, but SpaceX eventually expects to land astronauts on Earth using the propulsion power of the SuperDraco engines.
SpaceX
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Elon Musk first unveiled the Dragon 2 about two years ago, saying it was a “modern 21st century spacecraft” that could land anywhere thanks to its SuperDraco thrusters.
SpaceX
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Now SpaceX has revealed that its Dragon can land not only on Earth, but also on Mars, as early as 2018.
SpaceX
SpaceX developed SuperDraco thrusters as part of the Dragon 2 spacecraft, the manned version of the original Dragon. Testing of the SuperDracos began in early 2012 using several thrust cycles on a test rig at SpaceX’s rocket development facility in McGregor, Texas.
Nominally, SpaceX used funds from NASA’s commercial crew program to develop the thrusters for a launch abort system that allows the crew capsule to quickly escape the rocket in an emergency during a launch. SpaceX successfully tested this system in May 2015 at the company’s Space Launch Complex 40 in Cape Canaveral, Florida.
While protecting the crew pod may be the primary purpose of the SuperDraco thrusters, SpaceX also plans to use them to land “anywhere” on Earth. Instead of relying on a system of parachutes, a craft equipped with SuperDracos has the flexibility of a helicopter. Here’s how the company plans to use SuperDraco thrusters to propel Red Dragon to land on Mars.
Most of what we know about the SuperDraco’s technical specifications come from a document SpaceX filed with the Federal Aviation Administration in late 2013, as part of an environmental review of engine testing at the MacGregor site. Each thruster can produce 16,400 pounds of thrust. But to maintain vehicle stability, the system’s total power with eight thrusters clustered in four pairs around the spacecraft is 122,600 pounds. Each bow thruster has a 20 cm exhaust nozzle, with an exhaust velocity of 2,300 meters per second. The system’s hypergolic propellant allows the Dragon 2 to accelerate from zero to 100 mph in 1.2 seconds.
SpaceX plans to conduct crewed tests of the SuperDraco-equipped Dragon 2 in 2017, in anticipation of a possible unmanned Red Dragon landing on Mars in 2018. If the SuperDraco thrusters bring Red Dragon to a spring-like stop on the surface of the red planet, more Mars missions are bound to follow. We will watch with great interest.