Which payload is considered passive in data capture?

The classification of a payload as "passive" in data capture relates to how it collects information from the environment. A passive payload does not emit its own energy to gather data; rather, it detects energy that is naturally present in the environment.

Electro-Optical (EO) sensors capture data by detecting visible light reflected from surfaces. They rely on ambient lighting conditions—such as sunlight or moonlight—to produce images. This makes EO sensors passive, as they are not sending out energy but rather observing and recording what is available in the environment.

In contrast, other types of payloads utilize their own energy to gather data. Infrared (IR) sensors can be seen as primarily passive in certain contexts, as they detect thermal energy from objects without emitting their own, but they may also involve active elements depending on the specific technology used (e.g., IR lasers). Hyperspectral sensors utilize active illumination for more accurate readings in some cases, and radar systems actively transmit and receive signals to measure distances and velocities, making them inherently active in nature.

Thus, EO sensors are accurately classified as passive, emphasizing their reliance on existing environmental light rather than generating energy for data capture.