Astronaut <a href="https://en.wikipedia.org/wiki/Gordon_Cooper" class="extiw" title="en:Gordon Cooper">L. Gordon Cooper</a> participates in Mercury water egress training.
He  is wearing a snorkel and holding a camera for underwater photography.
NASA
Taken on 12 September 1962
<a rel="nofollow" class="external free" href="https://images.nasa.gov/details-s62-05161">https://images.nasa.gov/details-s62-05161</a>