A concept for hemispherical descent imaging for planetary science

Surface imaging is a key source of planetary science data throughout the solar system. As technology advances and science priorities evolve, novel exploration methods—such as aerial drones (e.g. Ingenuity, Dragonfly) or descent probes (e.g. DAVINCI)—increasingly characterise upcoming planetary science missions, providing new opportunities and challenges for conducting surface imaging.

We present an imaging concept for a wide-angle descent imager to capture downward-looking images with a full hemispherical field of view during a descent to a surface. Hemispherical descent imaging provides a multi-resolution view of a surface with high resolution in a localised area, and lower-resolution contextual information in a large surrounding area, with smooth, continuous transition in resolution, unlike nested orbital images. This wide-angle coverage enables geological analysis that bridges orbital and landed imagery; provides photometry over a wide range of viewing angles; and enables unique 3D terrain reconstruction.

Using field emulation and image simulations, we characterise the data return of a hemispherical descent imager. Close to optimal resolution and coverage can be achieved with relatively few (~5-10) images, suiting the technique to short-lived, high-speed descents. This technique is a compelling option for performing planetary surface imaging from small, low-cost descent probes. We discuss potential use cases and how returned data can enable novel planetary science.