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| The Mars Curiosity rover’s controlled descent utilized propulsion rockets aimed at the surface for a gentle landing, relying on a pyrovalve to release rocket fuel during the process, as illustrated in Perseverance’s sky crane landing system. |
The Curiosity and Perseverance rovers continue to enhance our understanding of Mars, thanks in part to their innovative sky crane landing systems. At the heart of their successful descents is a crucial component: a specially designed valve.
According to Carl Guernsey, propulsion subsystem chief engineer for the Mars Sample Laboratory Mission, the rovers’ engines, each producing approximately 750 pounds of thrust, required a unique solution for fuel delivery. “With the engines pointing down, we throttle up to slow down during descent,” he explained. This process involves holding a constant velocity at a specific altitude to gather sensor data before proceeding with the landing.
The precision of this landing process, which allows for last-minute adjustments, relies heavily on fuel availability at critical moments. To address this, NASA collaborated with a company known for its reliable gas regulators since the 1950s, now part of Eaton in Orchard Park, New York. Under contract with NASA’s Jet Propulsion Laboratory, the company created a groundbreaking one-time-use pyrovalve, notable for its zero-leak design and size—three-fourths of an inch, the largest of its kind at the time.
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| The one-time-use pyrovalve, developed by Eaton, sat between the hydrazine fuel tank and the controlled-descent engines on the Curiosity and Perseverance rovers, ensuring zero fuel loss during their journey to Mars. |
This Y-shaped valve features solid metal barriers to prevent propellant flow until activated. A pyrotechnic charge triggers a piston, or “flying ram,” that shears off these barriers, allowing fuel to flow. However, flight qualification testing revealed a challenge: the ram sometimes became wedged, risking blockage.
The team innovated by incorporating magnets at the bottom of the valve—a first for such applications. The successful landing of Perseverance in 2021 confirmed the effectiveness of this solution. Now, the same valve technology is also enabling commercial rocket-stage separation in space, showcasing its versatility and reliability.
