That is the most complex variant on tube-launch that I've ever read. Steam or compressed-gas tube launch is much easier, but doesn't scale much above ICBM sizes. This is the rusty, failure-prone and dangerous version of what US and Russian sub-launched missiles have done for a long time. <br /><br />Personally, I wouldn't want to be in that tube. Any failure and you are suddenly stuck a kilometer below the surface with no diving gear and no sub, just a jammed (fully fuelled) rocket. <br /><br />The failure modes on this are bewildering. You'd have a better chance of building the mag-lev-laser-launch system that Marshall Savage proposed.<br /><br />Josh <div class="Discussion_UserSignature"> <div align="center"><em>We need a first generation of pioneers.</em><br /></div> </div>