Click2Disasters - Challenger Explosion - Chapter 7

<body link="0000ff" alink="ff0000" vlink="000000" bgcolor=000033> <table width="100%" bgcolor=000033> <tr> <td align=center valign=top> <table width=90% bgcolor=ffffff> <tr> <td align=center valign=top> <tr> <td> <div align=center><p><b><font face="arial, helvetica" size=5 color=000000><b><i>CHALLENGER</i> EXPLOSION</p></b></font> <p><font size="4">CHAPTER 7 - THE EXPLOSION</b></font></p> <center> <table width="90%"> <tr> <td align="left" valign="top"> <div align="justify"> <p><font face="arial, helvetica" color="000000" size="3">As <i>Challenger</i> ascended, it encountered tremendous wind shears <a href="http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/rogers-commission/Chapter-4.txt" target="_blank"><b>32 to 62 seconds</b></a> after liftoff. They were the worst wind shears any shuttle had ever faced. Already weakened by the cold weather, the O-rings (which may have been resealing after liftoff) lost all chance to keep from completely eroding. </p> <p>As the O-rings eroded, the aft field joint came completely out of alignment. A gap had opened through which blow-by gases could come in contact with <i>Challenger's</i> external tank. The potentially fatal failure cycle - known to <a href="http://www.me.utexas.edu/~uer/challenger/figure7.html" target="_blank"><b>responsible officials</b></a> before liftoff - had commenced. </p> <p>At 58.32 seconds, an unusual plume in the lower part of the right Solid Rocket Booster was <a href="http://images.jsc.nasa.gov/images/pao/STS51L/10062366.jpg" target="_blank"><b>recorded</b></a> by cameras tracking <i> Challenger's</i> liftoff. At <a href="http://images.jsc.nasa.gov/images/pao/STS51L/10062363.jpg" target="_blank"><b>58.772 seconds</b></a> the first indication of smoke is visible from the right SRB. A fraction of a second later, at 58.778, the "first flickering <a href="http://images.jsc.nasa.gov/images/pao/STS51L/10062373.jpg" target="_blank"><b>flame</b></a> appeared on the right SRB in the area of the aft field joint." By <a href="http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/rogers-commission/Chapter-3.txt" target="_blank"><b>59.262</b></a>, the flickering flame had <a href="http://images.jsc.nasa.gov/images/pao/STS51L/10062374.jpg" target="_blank"><b>grown</b></a> into "a continuous, well-defined plume."</p> <p>At 64.660 seconds after liftoff,</p> <blockquote><font face="times new roman" size=3 color=000000><b><i>...there was an abrupt change in the shape and color of the plume. This indicated that it was mixing with leaking hydrogen from the External Tank...Within 45 milliseconds of the breach of the External Tank, a bright sustained glow developed on the black-tiled underside of the Challenger between it and the External Tank.</i></b></font></blockquote> <p>Meanwhile, the crew was given the command to give the shuttle more power: </p> <center><b><i><font face="times new roman" size=3 color=000000>You are go at throttle up</font></i></b></center> <p>The last response ever audibly heard from <i>Challenger</i>, rebroadcast many times the night of the disaster, was: </p> <center><font face="times new roman" size=3 color=000000><b><i>Roger, go at throttle up </i></b></font></center> <p>People watching the news that night took some small measure of comfort from those last words: "At least they never knew what happened." </p> <p>Except - those were <b>not</b> the last recorded words recorded by <i>Challenger's</i> crew.</p> </div> <p align="center"><font size="2"><a href="challenger_explosion_ch6.htm">GO TO LAST CHAPTER</a>     <a href="challenger_explosion_ch1.htm">BACK TO FIRST CHAPTER  </a>   <a href="challenger_explosion_ch8.htm">GO TO NEXT CHAPTER</a></p><br> </td> </tr> </table>  </td> </tr> </table>  </td> </tr> </table> </body>