On 21 June 2014 13:37, 'Chris de Morsella' via Everything List < [email protected]> wrote:
> *From:* LizR <[email protected]> > *To:* [email protected] > *Sent:* Friday, June 20, 2014 6:10 PM > > *Subject:* Re: Solar power's "bright future" > > >>That raptor rocket surely doesn't have *much* higher delta V than, say, > the Saturn 5? No chemical reaction is going to be that much more efficient, > no matter that you turn it into a superheated flying bomb. Surely for human > exploration beyond the Moon you really need (a) a moon base, (b) and > orbital assembly plant supplied from the moon base, and (c) some form of > nuclei/ion propulsion for your long haul space craft (which also need > shielding, of course!) > > I agree -- nothing I have heard about really improves on the chemical > potential of H2(liquid)/LOX. The advantage of LNG is not that it is pound > for pound a better fuel/oxidizer combo than liquid hydrogen/LOX (Saturn 5), > because it isn't, but rather because LNG fuel allows for significantly > longer longevity of the rocket fuel tanks and rocket motors components > themselves. Hydrogen causes metals to become brittle; whereas LNG does not > (or does not to the degree that hydrogen does). On a long duration mission > -- say to Mars and back -- it becomes rather important that the rocket > engine components do not wear out prematurely. That would be a real bummer, > for the unlucky astronauts. > > The innovative aspects of the Raptor engine are not just in terms of the > type of fuel it uses, but also because it uses separate turbo injection for > the LNG and LOX using floating bearing (essentially the spinning parts of > the turbo pump actually are floating on a very thin film of the LOX or LNG. > This also very significantly improves rocket engine life (those bearings > wear out fast). And by (apparently) choosing to use separate turbo pumps > for the LNG and the LOX it removes a catastrophic failure point for designs > that employ a single turbo pump with a diaphragm separating the LOX from > the fuel (whatever it is) -- if the diaphragm fails in such a design it is > an almost guaranteed catastrophic failure. > > Again I agree -- if we are ever going to become a space fairing > civilization we need to learn to live off the land (the land up there). The > moon has a very much smaller gravity well than planet earth; it just seems > to me to make sense to get the mass of fuel and LOX at the very least and > perhaps other materials as well from there (or from NEO asteroids as well) > Yeah, having a long lasting booster isn't much use if you can only fire it for a few hours. (Antimatter wears out your rocket even faster than hydrogen, but it sure gets you there a lot quicker!) > > >>Or use chemical propellant to rendezvous with one of those asteroids I > mentioned, then sit back and wait out the 9 months or so to Mars. > (Preferably installing a permanent base in the asteroid, which effectively > becomes a mars shuttle.) > > The asteroid Eros 433 would seem to fit the bill for a transit station. > It is fairly big (the second largest NEO in fact); it is an Amor type > asteroid and is a Mars crosser. > It comes within something like 20 million miles of Earth, I think, so yes a distinct possible. (And it isn't an alien space ship, as it turned out to be in a story I wrote when I was about 12. Oh well, predicting things is hard, especially the future.) > > >>I wish I could type this without my hands shaking with excitement. We're > actually trying to go to Mars!!!!!! > > I really hope so :) > Chris > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > > > -- > You received this message because you are subscribed to the Google Groups > "Everything List" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/everything-list. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
