Designing for Functional Vision in the Harsh Lighting of the Lunar South Pole
Designing for Functional Vision in the Harsh Lighting of the Lunar South Pole
As humans prepare to return to the moon for extended stays, NASA has selected the Lunar South Pole (LSP) as the location for its next mission, due to its optimal conditions for communication with Earth, solar visibility, and access to water ice. However, the unique lighting environment at the poles poses significant challenges for astronauts’ functional vision, making it a critical area of focus for NASA. At the Lunar South Pole, the sun remains low on the horizon, never rising more than a few degrees above the surface. In the target landing regions, the maximum elevation of the sun is only 7°, resulting in harsh lighting conditions that astronauts have never encountered, either during the Apollo missions or any other human spaceflight missions.
This limited sunlight creates a difficult visual environment, impairing astronauts’ ability to spot hazards and perform tasks. Despite the human visual system’s high-dynamic range, it struggles to function effectively in bright light and has difficulty adapting from bright to dark environments. Astronauts will need functional vision to perform both simple tasks, such as walking and using tools, and more complex tasks, such as operating rovers or landers. This creates an engineering challenge that must be fully understood and addressed in advance of future missions.
Previous NASA missions, like Apollo, handled vision support systems on a smaller scale, relying on mission planning and the astronauts' positioning to manage sunlight exposure. However, the Artemis missions face new challenges, as astronauts will not be able to avoid the sun’s glare while on the lunar surface. Additionally, extensive shadowing at the LSP will require artificial lighting, further complicating vision support needs.
To address this, NASA will need to develop comprehensive vision support systems. Helmet designs, windows, and lighting systems must work together to allow astronauts to see in both bright and dark environments without compromising their vision or eye safety. The challenge is to enable astronauts to maintain functional vision while adapting to sudden changes in lighting, such as moving from bright sunlight into shadow, without the risk of tripping or falling.
The assessment revealed that current designs lacked specific requirements to prevent vision impairment from the sun’s brilliance. For instance, spacesuit designs allow flexibility for astronauts to walk but do not account for the need to see clearly while transitioning between light and dark areas. The study also identified gaps in the allocation of requirements across different programs, preventing a unified approach to functional vision.
In response, the NASA Engineering and Safety Center (NESC) made several recommendations, including establishing functional vision as a key requirement for system designers. They also recommended integrating lighting, window, and visor designs to ensure comprehensive vision support for astronauts in the harsh lighting conditions of the Lunar South Pole.