V
vogon13
Guest
<p>Update on Orion:</p><p> </p><p>EMP effects of high altitude nuclear detonations have been noted and studied. Nukes ranging from 1 KT to over 1MT have been detonated in space. The primary EMP effect is due to gammma radiation released at the instant of detonation causing electrons in surrounding materials to be stripped away from their respective atoms and propelled radially away from the site of the explosion. This is a large current and can be quite a serious problem. After the blast, there is of course, a flow of electrons back towards the site of the explosion, but this current flow is energized by electromagnetic effects (opposite charges attract and therefore any large charge is rapidly neutralized) and not gamma radiation. (Incidentally, this effect is yet another coffin nail for the Electric Universe folks) </p><p> </p><p>In the propulsion units proposed for the Orion Project, wasting a large fraction of the bomb yield in gamma rays harms the overall efficiency of the method. The gamma rays impinging on the pusher plate yield little reaction effect and everyone is correct in worrying about large currents that might be induced in the pusher plate. But recall, the design of the propulsion modules utilizes low Z materials in the radiation channel of the bomb. This material absorbs the initial radiation pulse from the nuclear reaction, and spreads it out over time. This is done to enhance the efficiency of the yield, and to spread the impulse out over time so as not to fracture the pusher plate from a high shock load.</p><p> </p><p>The bomb actually releases comparably little gamma radiation in the direction of the vehicle. Effective temperature of the nuclear device blast the pusher plate 'sees' is in the 100,000K range, not the multi-millionK temperature of an 'ordinary' nuke. </p><p> </p><p>Should EMP effects still be a problem, a palliative measure would be to add small amounts of a light metal to the proposed 'oil' mix discussed for application to the pusher plate between detonations. I am thinking aluminum would be fine. Or perhaps putting the metal in the radiation channnel with the filler material would be preferred.</p><p> </p><p>Also, recall the detonation rate is scaled to the size of the vehicle. 1 per second detonations would only occur for the very smallest Orion vehicles. Recall the pulse rate for the large interstellar Orion craft is ~1 nuke per minute. Intermediate sized vehicles would have intermediate pulse rates.</p><p> </p><p>Regarding cost, Dyson envisioned the instellar Orion vehicle being financed over ~400 years. Contemplate underwriting the cost (not the technology) of a Nimitz class aircraft carrier in 16th century Britain. Ouch! Yet such vehicles today (~400 years later) are a comparative bargain.</p><p> </p><p>Don't worry about sticker shock on an interstellar Orion vehicle.</p><p> </p><p>Regarding environmental damage, contemplate one Orion launch lofting 4000 tons(!) of payload versus the number of Soyuz or shuttle launches needed to lift the same load. (note,using boron in the radiation channel filler material of ground launced Orions has been studied to reduce radioactivity effects) I am thinking the environmental damage for conventional propulsion vs. Orion (considering the enviromental effects of building the Soyuz's and shuttles in addition to launching them) is overwhelmingly less for the Orion vehicle.</p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p><p> </p> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>