Article by: Staff
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Space Exploration Technologies (SpaceX) is continuing with their development of the Crew Dragon capsule, which is being built for NASA per the Commercial Resupply Services (CRS) agreements. The evolution in Dragon design has been shaped by the CRS contract drawing a line between a cargo version and a crew version.
Dragon v1 has been responsible for delivering 10 cargo shipments to the International Space Station (ISS). Crew Dragon, or Dragon v2, will fly crews to Low Earth Orbit (LEO) as early as 2018, thereby re-enabling the United States to transport its astronauts into space from their home ground.
In Florida, at the Kennedy Space Center (KSC), engineers are building a full-scale model, or Recovery Trainer, of the Crew Dragon capsule. Training is best executed when real artifacts or carefully created test articles can be utilized in real-world scenarios. This training is essential for everyone involved to assist in better defining procedures when things go wrong and lives are at stake.
The Dragon Recovery Trainer has been constructed with the aid of the Kennedy Prototype Lab, which has a history of providing fast solutions to complex design challenges. SpaceX is putting the finishing engineering touches into the Recovery Trainer to ensure that it will float identically to how an actual Dragon v2 will with a crew present.
NASA has a documented history of test flights and practice runs that ensure the flight crew, support crew, and emergency personnel are able to perform as expected during an emergency event. One notable incident was Gus Grissom in Liberty Bell 7 when the hatch prematurely blew on his capsule and suddenly the Navy was faced with a drowning astronaut and a sinking capsule. It is critical to ensure that both crew and rescue personnel know what to do in case of an emergency.
Unlike Liberty Bell 7, the Crew Dragon can carry up to seven astronauts, which makes evacuation more challenging. Two escape hatches and other various components within the Recovery Trainer will be present to better reflect a real-world environment for astronaut crew and Pararescuemen, also known as PJs.
USAF Pararescuemen will be required to enter the water to assist in any number of rescue scenarios where a crew may or may not be able to assist in their own recovery. This is an exercise that neither NASA nor the USAF takes casually and both organizations will invest many practice hours to ensure a safe environment and rapid execution of rescue.
The real SpaceX Dragon v2 spacecraft has numerous features integrated into the design to ensure that it is a very safe ship. It has an integrated thrust system that incorporates four pairs of two SuperDraco engines, each engine providing about 16,000 lbf (71.2 kN) of thrust each. The SuperDraco engines are not only designed to lift the Dragon v2 with a crew away from a launch mishap to safety but also will allow the spacecraft to land anywhere on Earth with the precision of a helicopter – even if two of the eight engines fail.
Each SuperDraco engine, created with a 3-D printing process using an Inconel superalloy, sits within an isolated nacelle. Additionally, if during a descent from orbit the computers detect any of the SuperDraco engines are suffering from an anomaly, the Dragon also has an integrated parachute recovery system that has robustness built into its design. To paraphrase Elon Musk’s feelings on the matter, he expressed confidence that if there is a safer way to design the capsule, he doesn’t know what that is.
Additionally, the PICA-X heat shield is a 3rd generation derivative minimizing ablation during re-entry allowing for maximum reflights of the hardware with minimal refurbishing effort. Finally, the gumdrop shape design allows for automatic orienting of the spacecraft through re-entry even if the flight computers are compromised.
In July 2011, the United States ended its capability to launch astronauts from its soil when Congress stopped funding the Space Transportation Shuttle (a.k.a. the Space Shuttle). Since then, NASA has paid for seats on Russia’s Soyuz spacecraft, thereby fulfilling the role of ferrying U.S. astronauts to and from the ISS.
Soon, Boeing and SpaceX will provide a crewed capsule capability with the CRS program to ensure that U.S. astronauts no longer have to rely on a foreign government for transportation to LEO – or beyond. Americans and Congress anticipate that day with pressing eagerness.