Which metric describes a spacecraft's ability to withstand radiation without functional failure?

• A. Latency
• B. Jamming-to-signal ratio
• C. Radiation hardness
• D. Spectral leakage

Answer: (C)

Radiation hardness describes a spacecraft's ability to withstand space radiation without functional failure. In the space environment, electronics are exposed to ionizing radiation that can degrade performance, cause timing errors, flip bits in memory, or even take systems offline. A higher radiation hardness means components and systems are designed, shielded, or selected to tolerate the expected radiation exposure, often quantified by how much total dose they can endure and how well they resist radiation-induced upsets. This concept is central to keeping avionics and sensors reliable over the mission, especially when passing through radiation belts or solar particle events. Techniques to achieve this include using radiation-hardened parts, employing shielding, and adding error-detection and redundancy to mitigate failures.

Latency describes the time delay between input and output in a system, which is unrelated to how much radiation a spacecraft can endure. Jamming-to-signal ratio measures how well a system resists intentional interference rather than natural radiation effects. Spectral leakage is a signal processing artifact that occurs when finite data windows spread energy across frequencies.