Analysis of Orion heat shield nears completion at NASA’s Marshall Center
A team of about a dozen engineers and technicians from three NASA centers has been working together in Building 4705 of NASA’s Marshall Space Flight Center in Huntsville, Alabama, to remove burnt ablative material and crucial sensors from the heat shield of the Orion spacecraft which was successfully launched during the Exploratory Test Flight-1 (ETF-1) mission in 2014. The team included thermal protection engineers from NASA’s Ames Research Center in Moffett Field, California, milling and machining engineers from Marshall, and thermal protection subsystem managers from NASA’s Johnson Space Center in Houston, Texas. Representatives from Lockheed Martin, the prime contractor who build both the Orion spacecraft and its heat shield for NASA, were also present. Under a Space Act agreement with Marshall, Lockheed Martin helped orchestrate the debris removal operation and provided additional ground support equipment and services.
On March 9, the heat shield was delivered to Building 4705 at Marshall, home to NASA’s state-of the art seven-axis milling and machining facility. The seven-axis machine uses precision, computer-aided tools which are able to move fluidly in a variety of ways to manufacture parts and cut large metal or composite materials. In this case, the seven-axis machine was used to cut and remove the majority of the the charred outer layer of the 16.5-foot-diameter heat shield. The ablative layer of the heat shield is made from a material called Avcoat.
“What began as a basic plan to remove the Avcoat became a successful team effort to extract critical data and prepare the heat shield for its next planned use,” said Terry Abel, Lockheed Martin’s technical liaison to Marshall.
Since May 4, the team has been working to remove the approximately 180 remaining small squares of Avcoat for analysis. Many of the squares contain data-gathering sensors which were designed and built at NASA Ames to gather environmental and thermal protection data as the Orion spacecraft re-entered the atmosphere and splashed down in the Pacific Ocean.
Once the final pieces are removed by hand, the chunks of ablated material and sensors will be prepared for shipment to Ames and other NASA centers for further research. The performance of the materials will be analyzed by the same teams at Ames that tested and qualified the materials before flight using the center’s Arc Jet Complex. Data from the samples and the behavior of the heat shield during re-entry will be used by researchers to refine their computer models. This will aid scientists and engineers to develop safer and more cost-effective thermal protective systems for future missions.
To finish up the heat shield milling process, the seven-axis milling machine will make a final pass with its cutting tool rotating at 7,000 rpm to cull material at a rate of more than 180 inches per minute. The machine’s built-in vacuum system will suck up the dust from the excised Avcoat material. The stripped Avcoat covering will than be smoothed to a uniform layer about one-tenth of one inch above the shield’s composite inner surface. The shield will be readied in early June for transfer to NASA’s Langley Research Center in Hampton, Virginia, for water-impact testing.
Analysis of the sensor data and heat shield material samples will take about 6 months. Then the findings will be shared with the Orion program team. This data will have an impact on the development of the next flight test vehicle, which will launch atop the Space Launch System (SLS) for Exploration Mission 1 (EM-1).
Video courtesy of NASA
Jim Sharkey is a lab assistant, writer and general science enthusiast who grew up in Enid, Oklahoma, the hometown of Skylab and Shuttle astronaut Owen K. Garriott. As a young Star Trek fan he participated in the letter-writing campaign which resulted in the space shuttle prototype being named Enterprise. While his academic studies have ranged from psychology and archaeology to biology, he has never lost his passion for space exploration. Jim began blogging about science, science fiction and futurism in 2004. Jim resides in the San Francisco Bay area and has attended NASA Socials for the Mars Science Laboratory Curiosity rover landing and the NASA LADEE lunar orbiter launch.