Which spacecraft studies the reaction between sunlight and earth's ozone layer?

The Solar Mesosphere Explorer is designed specifically to investigate the interactions between solar radiation and the Earth's atmosphere, including its ozone layer. By focusing on these reactions, the spacecraft gathers crucial data on how sunlight influences atmospheric processes, particularly in the mesosphere, where ozone plays a key role in absorbing solar ultraviolet radiation. This understanding is vital for assessing the impacts of solar activity on atmospheric chemistry and global climate change.

The other options do not primarily focus on the relationship between sunlight and the ozone layer. The Earth Radiation Budget Satellite, for instance, is more concerned with measuring the Earth's energy balance, while the Earth Observatory System encompasses a range of satellite missions intended to monitor various environmental and atmospheric conditions rather than specifically studying ozone. The Lunar Orbiters, on the other hand, are primarily focused on lunar exploration and mapping, unrelated to Earth's atmospheric studies.