SPACE SCIENCE
'(<a href="http://www.j-archive.com/media/2008-06-12_DJ_25.jpg" target="_blank">Kelly of the Clue Crew shows some punctured metal tiles.</a>) To evaluate materials like <a href="http://www.j-archive.com/media/2008-06-12_DJ_25a.jpg" target="_blank">shuttle shielding</a>, projectiles are fired at speeds up to 16,000 miles per hour using this simple gas, compressed'
hydrogen