NEEMO 14 aquanauts, biomedical engineer <a href="https://en.wikipedia.org/wiki/Andrew_Abercromby" class="extiw" title="en:Andrew Abercromby">Andrew Abercromby</a> (left) and Aquarius habitat technician <a href="https://en.wikipedia.org/wiki/Nate_Bender" class="extiw" title="en:Nate Bender">Nate Bender</a>, performing communication checks from the Aquarius underwater habitat during the NEEMO 14 mission in May 2010.  NASA photo JSC2010-E-077813 in public domain.
NASA
<a rel="nofollow" class="external free" href="http://spaceflight.nasa.gov/gallery/images/behindthescenes/training/html/jsc2010e077813.html">http://spaceflight.nasa.gov/gallery/images/behindthescenes/training/html/jsc2010e077813.html</a>