What Do These Names Have In Common? [Science Tattoo]

After I saw this tattoo over on a sibling blog, Science Not Fiction, I knew it had to join the emporium. Its owner, Mark Yturralde, sent me this description of its origin:

After the Columbia accident, I felt compelled to do something. Space has always meant so much to me, and I felt I wanted to memorialize them somehow.

I donated to college funds and other charities in their name, but still felt like I needed to do more, and I found myself reliving and considering Challenger, and Apollo one too,