Sandia Labs Advances Spacecraft Heat Shield Testing for Mars and Titan Missions

Sandia National Laboratories is at the forefront of aerospace engineering, particularly in the evaluation and testing of heat shields critical for upcoming NASA missions to Mars and Titan. In a bold move to harness solar energy, Sandia’s National Solar Thermal Test Facility conducts simulations of the extreme conditions that spacecraft endure during atmospheric reentry and hypersonic flight. This innovative approach not only enhances the efficiency of testing but also offers significant cost savings compared to traditional methods.

The Mars Sample Return mission, a collaborative venture between NASA and the European Space Agency, aims to bring Martian rock samples back to Earth for analysis. These samples hold the potential to unlock secrets of ancient life on Mars and are pivotal in preparations for future human exploration of the Red Planet. According to Ken Armijo, a Sandia engineer and test director, the Sample Retrieval Lander will transport the heaviest payload ever sent to Mars. “The heavier the payload and the bigger the entry vehicle, the hotter the vehicle gets during atmospheric entry, and the better the heat shield needs to be,” he explains.

To prepare for such challenges, Sandia’s testing facility utilizes hundreds of heliostat mirrors to focus sunlight, simulating the intense heat experienced during reentry. This solar testing method efficiently mimics atmospheric conditions, allowing engineers to subject samples up to three feet wide to extreme temperatures. Unlike traditional methods such as arc jets and lasers, which consume vast amounts of energy, Sandia’s solar testing saves between 15,000 to 60,000 kilowatts per test, equivalent to powering thousands of clothes dryers at once.

The solar power tower, which stands at 200 feet tall and features 212 heliostats, creates an environment where high flux and high flux distribution can be achieved. This capability especially important for testing materials under conditions that mirror hypersonic flight. Armijo highlights the facility’s ability to concentrate sunlight up to 3,500 times its normal intensity, providing precise control over heat exposure. The cost-effectiveness of this method is noteworthy, with solar testing averaging about ,000 per day compared to 0,000 for arc jet tests and 0,000 for laser testing.

Navigating the complexities of space exploration also includes addressing the unique challenges posed by Titan, Saturn’s largest moon. NASA’s Dragonfly mission aims to explore Titan’s methane-rich atmosphere with a rotorcraft capable of flying across its surface. For this mission, heat shield materials made from Phenolic Impregnated Carbon Ablator, first developed at NASA’s Ames Research Center, are being tested at Sandia. Daniel Ray, a mechanical technologist at Sandia, emphasizes the importance of making the testing process function smoothly. He recalls overcoming challenges during tests, such as preventing fires caused by carbon felt by designing protective ceramic shields.

To recreate Titan’s atmospheric conditions, Sandia engineers blow nitrogen gas over heat shield samples during tests. This innovative setup, including a newly installed gas line that runs from the base to the top of the power tower, ensures that adequate gas flow is maintained during experimentation. This attention to detail is reflective of Sandia’s commitment to supporting NASA’s missions effectively.

In addition to its work on Mars and Titan, Sandia has also contributed to the Applied Physics Laboratory’s tests on a heat exchanger prototype designed for future spacecraft. This prototype demonstrated resilience under extreme stress levels, enduring light levels equivalent to 2,000 suns and reaching temperatures of 3,100 degrees Fahrenheit during testing. Such achievements highlight the lab’s extensive experience across various aerospace projects, including previous evaluations for space shuttles and military aircraft.

As the evolution of space exploration continues, confidence in the durability and functionality of spacecraft materials is paramount. Armijo notes, “Because we can dial-in the profiles, we have more confidence that it is going to survive and function well during a mission.” This meticulous approach ensures that the next generation of space missions can safely transport precious samples from distant worlds back to Earth, while also laying the groundwork for human exploration beyond our planet.