From our planet, space appears as a dark, cold void. However, the reality for those who venture beyond Earth's protective blanket is starkly different. Sunlight in space is brutally harsh, unfiltered by atmosphere, clouds, or the ozone layer. This leads to a fascinating and serious question: do astronauts need to wear sunscreen when they are in space?
The Deadly Nature of Unfiltered Sunlight in Space
Sunlight is more than just the visible light we see. It is part of the electromagnetic spectrum, which includes invisible ultraviolet (UV) rays. On Earth, we benefit from moderate UVB exposure for vitamin D synthesis. However, excessive UV radiation damages skin cell DNA, leading to sunburn and a heightened risk of skin cancer.
Scientists classify ultraviolet radiation into three main types. UVA rays have the longest wavelength and penetrate deep into the skin. UVB rays affect the surface layers and are primarily responsible for sunburns. The most dangerous, UVC radiation, is almost entirely blocked by Earth's ozone layer. This natural shield is what makes life under the sun possible. In the vacuum of space, this protection vanishes completely.
Spacesuits: The Ultimate Personal Sunblock
Given the extreme radiation environment, one might assume astronauts suffer severe burns. Yet, history shows otherwise. During the Apollo Moon missions, no astronaut returned with sunburn. The reason is not a lack of danger but superior human engineering.
Astronauts do not carry tubes of SPF cream. Instead, they rely on their spacesuits, which function as personal spacecraft. The suits' thick, multi-layered fabrics are designed to block ultraviolet radiation entirely. The helmets, though they look like clear bubbles, are formidable shields. They are constructed from ultraviolet-stabilised polycarbonate, a tough plastic that stops harmful rays from reaching an astronaut's face.
Visors can often be adjusted for different lighting conditions, protecting both skin and eyes. Without this shielding, astronauts could experience a condition similar to snow blindness or sustain permanent eye damage from the intense glare. The suit's comprehensive design makes the application of traditional sunscreen not just unnecessary but practically irrelevant.
Notable Exceptions and Internal Safety
There has been one famous incident where this protection failed. In 1963, during the Gemini 9 mission, astronaut Gene Cernan performed a spacewalk. A tear in the seams of his spacesuit exposed a part of his back to the full force of solar heat. He returned to the spacecraft with a distinct, triangular-shaped sunburn, a stark reminder of space's unforgiving nature.
Inside spacecraft like the International Space Station, the risk plummets. Astronauts wear regular clothing—t-shirts and trousers—as they float through the modules. The station's windows are equipped with special filters that block ultraviolet light, allowing crews to enjoy the breathtaking view of Earth without the harmful effects. This principle of allowing visible light while filtering out dangerous radiation is standard in modern spacecraft design.
The Moon's Silent Transformation
While astronauts have been protected, the Moon's surface has not been so lucky. An interesting side effect of constant, unfiltered solar radiation may be visible on the iconic American flags planted during the Apollo era. Scientists theorise that decades of intense UV exposure have likely bleached the once-vibrantly coloured flags white. It is a quiet testament to the power of sunlight where there is no atmosphere to soften its blow.
So, do astronauts need sunscreen in space? The definitive answer is no. Not because space is safe, but because human ingenuity has engineered a solution far more effective than any lotion. In the final frontier, protection isn't smeared on the skin; it is built around the entire body, allowing humanity to explore the cosmos one safe spacewalk at a time.
