In this image, the Pressurized Mating Adapter 2 (PMA 2) on the forward end of the Destiny U.S. Laboratory module is shown as the Orbiter Discovery moved in to dock with the International Space Station (ISS) during STS-121. 
<p>Image #: s121e05621
</p>
Date: July 6, 2006
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/44494372@N05">NASA on The Commons</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/nasacommons/19290352492/">STS-121 Docking with ISS</a>