<font color="yellow">"Hybrid's relibility and performance are inferior to other cofigurations, such as pressure fed hypergolics and engine out configurations, otherwise NASA (who is happy to pay 10bln for a little extra safety) would be using hybrids on their LVs, SMs and LSAMs."</font><br /><br />I think the jury is still out concerning the reliability and performance of hybrids. It's true that there is not enough of an experience base with large hybrids, but this is rapidly changing. SpaceDev is a leader in this technology. They might know something about this that you and I don't know.<br /><br />NASA doesn't use hybrids because they have the cash (i.e., tax payer dollars) to pay for bleeding edge technology, higher ISP systems. A government agency can afford to do that. SpaceDev is a business and must make a profit somehow.<br /><br /><font color="yellow">"Even if the engine has 100% reliability, there is still software, TVC and other things to go wrong."</font><br /><br />Some things are common to all propulsion methods. Those things can cause problems with liquids and solids as well. With all due respect, what's the point of bringing that up?<br /> <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>