SpaceX, the California company that is developing the reusable Dragon spacecraft, recently test-fired its new SuperDraco engine. Presently, the Dragon capsule is equipped with less-advanced Draco engines, which are designed for maneuvering the spacecraft while in orbit and during reentry. The SuperDraco, however, is intended to allow the astronauts to escape if an emergency occurs during the launch.
Plans call for eight of the engines to be installed in the outer side walls of the Dragon. Together, these will create 120,000 pounds (54,431 kg) of axial thrust. Should something go wrong with the Falcon launch rocket while the spacecraft is lifting off, the SuperDracos will fire, allowing the Dragon to separate and fly to safety.
SpaceX claims that the new engines will have several advantages over those used by other spacecraft. For starters, they will remain attached to the Dragon throughout the entire launch, unlike other systems that are jettisoned within a few minutes of lift-off. They can also be restarted multiple times within one flight, and have the ability to deep throttle, which should reportedly provide the astronauts with "precise control and enormous power."
Additionally, like the Dragon and the Falcon, the SuperDracos will be reusable - one set should be good for numerous flights. If one of them does fail, the escape system is designed to still work successfully using the remaining seven.
Besides their use in emergencies, the engines could also be used to perform precise "propulsive landings" on Earth or other planets. In this scenario, by varying the downward thrust of the engines, astronauts could gradually lower the Dragon to the ground.
The SuperDraco engine was developed using a US$75 million grant that NASA's Commercial Crew Program awarded to SpaceX last April. The ground tests were conducted at the company's Rocket Development Facility in McGregor, Texas, where the engine sustained full-duration, full-thrust firing, and performed multiple demonstrations of deep throttling.
Some of those tests can be seen in the video below.
Hydrazine is the standard fuel for things like spacecraft attitude thrusters. It makes for simple engines, and it\'s a hypergolic fuel, so ignition is assured, but it\'s nasty stuff. It\'s toxic, and it will ignite on contact with any oxidizer.
There has been talk about replacing hypergolic fuels with less toxic fuels like peroxide-based monopropellants, but I guess that day has not yet arrived.
Why does there always have to be at least one person that is so negative about everything?
As is evidenced by our virtual inability to build certain things, environmental politics makes for a poor companion for engineering.
Glad to see Dragon is progressing.
The liftoff fuel that SpaceX uses is kerosene not Hydrazine. Hydrogen is energy intensive to extract and liquify and vast quantities are boiled off with every transfer. Kerosene is currently the less polluting fuel.
Your alternative h2o2, will spontanius decombust in rocket grade concentrations... But what, it was shipped on the same trains that carried hydrazine. Consider the reaction if two tanks got mixed...
The protocols regarding the use of hydrazin, are so well proven over the past 70 years that it\'s probably the simplest and safest option available.
Btw. Given the current safty procedures gasoline would never have been aproved for use in cars today. It\'s just do da%#$% dangerous.