Subjected to temperatures as high as 1850 degrees Celsius (3360 degrees Fahrenheit), the tests simulated the reentry heating conditions that will be experienced by the Dragon capsule. Panels of the high performance carbon-based material will protect cargo and crew during the spacecraft’s return from Earth orbit. SpaceX developed the ability to manufacture PICA-X with the assistance of NASA, the originator of PICA (Phenolic Impregnated Carbon Ablator). The “X” stands for the SpaceX-developed variants of the rigid, lightweight material, which has several improved properties and greater ease of manufacture.
The tests were conducted at the Arc Jet Complex at NASA Ames Research Center, Moffett Field, California, which has a rich history in the development of Thermal Protective Systems for NASA spacecraft, including Apollo, Space Shuttle, and robotic missions to Venus, Mars, and Saturn. The NASA Ames Arc Jet Complex is uniquely capable of simulating conditions experienced during reentry. “The arc jet tests represent the culmination of an aggressive six-month development effort, and our goals have been met or exceeded,” said Elon Musk, CEO and CTO of SpaceX. “Dragon will be the first craft to return from Low Earth Orbit using a PICA-based thermal protection system.”
SpaceX is only the second commercial producer of a PICA-based material. All of SpaceX’s initial production will be used for domestic in-house applications including the heat shields of the Dragon spacecraft, and the Falcon 9 second stage, which is designed to return from orbit for recovery and reuse. The inaugural Dragon spacecraft flight is scheduled for 2009 aboard SpaceX’s new Falcon 9 launcher. The Dragon capsule will enter the Earth’s atmosphere at around 7 kilometers per second (15,660 miles per hour), heating the exterior of the shield to up to 1850 degrees Celsius. However, just a few inches of the PICA-X material will keep the interior of the capsule at room temperature. In January 2006, NASA’s Stardust sample return capsule, equipped with a PICA heat shield, set the record for the fastest reentry speed of a spacecraft into Earth’s atmosphere — experiencing 12.9 kilometers per second (28,900 miles per hour). SpaceX’s Dragon spacecraft will return at just over half of that speed, and will experience only one tenth as much heating.
(Image: Dragon and Falcon 9 Second Stage, post Second Stage Separation Event. Courtesy NASA)
