<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>On Dec 23, 2015, at 8:39 AM, spike <<a href="mailto:spike66@att.net">spike66@att.net</a>> wrote:</div><blockquote type="cite"><meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="Generator" content="Microsoft Word 15 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--><div class="WordSection1"><p>On Dec 22, 2015 19:22, "Dan TheBookMan" <<a href="mailto:danust2012@gmail.com">danust2012@gmail.com</a>> wrote:<br>><br>><span style="color:#1F497D">>…</span> I'm guessing, without have done any research, this first one will be dissected and analyzed to see what the wear and on it is like. Am I wrong about that?<o:p></o:p></p><p><span style="color:#1F497D">>…</span>I am sure you are right about that. Still experimental, though I suspect a fast tempo<span style="color:#1F497D">… Steve<o:p></o:p></span></p><p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p><p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">We can build re-startable rocket motors if we accept the weight penalty. We already do that for some applications. The one-use throwaways sacrifice everything to get weight down. <o:p></o:p></span></p><p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">It is completely believable to me that Musk’s group has developed a gas-and-go rocket motor. </span></p></div></blockquote><div><br></div><span style="background-color: rgba(255, 255, 255, 0);">Of course, that the engines been fired again during flight seems to say you're right here.</span><div><br></div><div>And they seem to have already mastered shutting down an engine during flight because of malfunction while keeping the mission going. Seems like the 'infrastructure' is in place for partial failures of reused engines, no?<br><blockquote type="cite"><div class="WordSection1"><p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Good chance he needs to run it fuel-rich to keep nozzle temperatures down out of the high-erosion regime, so there are known performance compromises to that approach. </span></p></div></blockquote><div><br></div>My guess is inspection and maybe pad firing tests after flight to see if an engine can be reused after each flight. It'd be nice to see this become so reliable it's like a commercial jet flight.<br><blockquote type="cite"><div class="WordSection1"><p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> But after all these years, I am convinced the lower performance reusable rockets are the way forward. </span></p></div></blockquote><div><br></div>Me too.<br><blockquote type="cite"><div class="WordSection1"><p><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"> I don’t know what SpaceX has in mind for recovering a second stage, but this tail-landing first stage is the most exciting development in space tech in a long time.</span></p></div></blockquote><div><br></div><div>Though it was the way rockets were depicting as landing for a long time in SF, no?</div><br><div style="line-height: normal;"><span style="line-height: 20px; background-color: rgba(255, 255, 255, 0);">Regards,</span></div><div style="line-height: normal;"><span style="line-height: 20px; background-color: rgba(255, 255, 255, 0);"><br></span></div><div><div style="line-height: normal;"><span style="line-height: 20px; background-color: rgba(255, 255, 255, 0);">Dan</span></div><div style="line-height: normal;"><span style="background-color: rgba(255, 255, 255, 0);"> Sample my Kindle books via:</span></div><div style="line-height: normal;"><a href="http://author.to/DanUst" style="background-color: rgba(255, 255, 255, 0);"><font color="#000000">http://author.to/DanUst</font></a></div></div></div></body></html>