Christopher Posted October 26, 2012 Report Share Posted October 26, 2012 Re: More space news! To answer the Original question: That's really slow. Is there a known upper limit for proven(i.e.' date=' stuff that's actually been used before) propulsion tech, and then a probable upper limit for known tech(stuff we kinda sorta know how to build but maybe haven't fully fielded yet)? Do either of these come remotely close to even .001 c?(i.e., 1/1000 of light speed).[/quote'] According to the studies that were made, the Nuclear Pulse Propulsion can do more than just .0001 c. A lot more: "Later studies indicate that the top cruise velocity that can theoretically be achieved by a thermonuclear (meant is fusion) Orion starship, assuming no fuel is saved for slowing back down, is about 8% to 10% of the speed of light (0.08-0.1c).[2] An atomic (fission) Orion can achieve perhaps 3%-5% of the speed of light. A nuclear pulse drive starship powered by matter-antimatter pulse units would be theoretically capable of obtaining a velocity between 50% to 80% of the speed of light. In each case saving fuel for slowing down halves the max. speed. At 0.1c, Orion thermonuclear starships would require a flight time of at least 44 years to reach Alpha Centauri, not counting time needed to reach that speed (about 36 days at constant acceleration of 1g or 9.8 m/s2). At 0.1c, an Orion starship would require 100 years to travel 10 light years. The astronomer Carl Sagan suggested that this would be an excellent use for current stockpiles of nuclear weapons.[13]" Quote Link to comment Share on other sites More sharing options...
Cancer Posted October 26, 2012 Report Share Posted October 26, 2012 Re: More space news! FWIW, the observability of such things with gamma-ray observatories has been worked out. There aren't any within a few hundred parsecs. Quote Link to comment Share on other sites More sharing options...
Old Man Posted October 27, 2012 Report Share Posted October 27, 2012 Re: More space news! Would we want there to be? 36 days to reach 0.1c is pretty good. What are we doing for deceleration at the far end? Solar sail? Quote Link to comment Share on other sites More sharing options...
tkdguy Posted October 27, 2012 Author Report Share Posted October 27, 2012 Re: More space news! Fomalhaut b regains planetary status Quote Link to comment Share on other sites More sharing options...
Christopher Posted October 27, 2012 Report Share Posted October 27, 2012 Re: More space news! Would we want there to be? 36 days to reach 0.1c is pretty good. What are we doing for deceleration at the far end? Solar sail? The figures that I cited are for "acceleration only" flights. The kind that you would use for probes or a asteroid deflection mission (note that those could also take more acceleration, about 25-50 what a human mission could do). If you want the figures for "accelerate, turn around, decellerate" flights you have to halve the top speed (as you need literally have the fuel for braking). The main problem with fuel efficiency is that we can't use most of the force a fission bomb produces (without killing the passengers), but we also can't build bombs smaler than what is proposed (it's the minimum critical mass - any less and there is not going to be a explosion for acceptable cost). The higher top speed of pure fusion* or antimater bombs comes not from higher yield, but that they could be built a lot smaller. Of course building it bigger/heavier also increases fuel efficiency (as unlogical as it sounds at first). *Tsar Bomb and all other "fusion bombs" use a conventional Fission Bomb as detonator, so they won't help us in any way. Quote Link to comment Share on other sites More sharing options...
AmadanNaBriona Posted October 29, 2012 Report Share Posted October 29, 2012 Re: More space news! Would we want there to be? If we'd detected the appropriate Gamma pulses it'd be pretty clear evidence of intelligent life fairly close to us. 36 days to reach 0.1c is pretty good. What are we doing for deceleration at the far end? Solar sail? Yeah, it's a pretty zippy drive system. There are a lot of issues that'd need to be worked out, but the payload and speed of an Orion ship makes it worth contemplation Edit: with a second glance, I mighta missed some nuance in your question there, Old Man. I guess no signs of NPP in nearby space means very little chance of us getting Footfalled, on the brighter side of the coin Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted October 29, 2012 Report Share Posted October 29, 2012 Re: More space news! Huh. I thought Orion was plug-pulled upon. Seems like I was mistaken! Quote Link to comment Share on other sites More sharing options...
Christopher Posted October 29, 2012 Report Share Posted October 29, 2012 Re: More space news! If we'd detected the appropriate Gamma pulses it'd be pretty clear evidence of intelligent life fairly close to us. Yeah, it's a pretty zippy drive system. There are a lot of issues that'd need to be worked out, but the payload and speed of an Orion ship makes it worth contemplation Edit: with a second glance, I mighta missed some nuance in your question there, Old Man. I guess no signs of NPP in nearby space means very little chance of us getting Footfalled, on the brighter side of the coin I would not count on it. A large part of the travel is just letting the momentum carry you. And with only 1-2 months to deceleration we could be surprised. Also noticing a shaped, minimum yield nuclear explosion in the vastness of space is not that easily. We have difficulty even noticing the gama and x-ray burst of supernovas. And those are a lot brighter. Without an atmosphere to ignite even the visible light might be rather moderate. Huh. I thought Orion was plug-pulled upon. Seems like I was mistaken! No, that is a totally different Orion Project. We talk about the Nulcear Pulse Propulsion Orion. The Orion Crew Capsule was afaik named to get the name away from "riding on atom bombs". Quote Link to comment Share on other sites More sharing options...
tkdguy Posted October 30, 2012 Author Report Share Posted October 30, 2012 Re: More space news! Dragon spacecraft returns to Earth NASA may launch a Canadian rover to the Moon or Mars Rocket fragmentation in orbit causes space debris Orion spacecraft: not quite dead yet Saving Earth from asteroids... with paintballs? Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted October 30, 2012 Report Share Posted October 30, 2012 Re: More space news! No, that is a totally different Orion Project. We talk about the Nulcear Pulse Propulsion Orion. You might be, but I'm not. Quote Link to comment Share on other sites More sharing options...
tkdguy Posted October 31, 2012 Author Report Share Posted October 31, 2012 Re: More space news! Martian soil is similar to Hawaiian soil? Possible Explanation for the Moon's Ocean of Storms Quote Link to comment Share on other sites More sharing options...
tkdguy Posted November 1, 2012 Author Report Share Posted November 1, 2012 Re: More space news! Carbon Streaks on Vesta's Surface Glow-in-the-dark Titan New Theory on Formation of Solar System's Earliest Materials Spacewalk to Find Ammonia Leak Quote Link to comment Share on other sites More sharing options...
tkdguy Posted November 2, 2012 Author Report Share Posted November 2, 2012 Re: More space news! Breaks in Earth's Magnetic Field Quote Link to comment Share on other sites More sharing options...
tkdguy Posted November 2, 2012 Author Report Share Posted November 2, 2012 Re: More space news! Storm in Saturn Quote Link to comment Share on other sites More sharing options...
McCoy Posted November 2, 2012 Report Share Posted November 2, 2012 Re: More space news! Storm in Saturn [ATTACH=CONFIG]45081[/ATTACH] Quote Link to comment Share on other sites More sharing options...
tkdguy Posted November 2, 2012 Author Report Share Posted November 2, 2012 Re: More space news! Curiosity does not detect methane on Mars. Quote Link to comment Share on other sites More sharing options...
Sociotard Posted November 2, 2012 Report Share Posted November 2, 2012 Re: More space news! And, as it has not smelled it, it may be presumed to have not dealt it. Quote Link to comment Share on other sites More sharing options...
tkdguy Posted November 3, 2012 Author Report Share Posted November 3, 2012 Re: More space news! Volcanic eruptions on Io Quote Link to comment Share on other sites More sharing options...
AmadanNaBriona Posted November 3, 2012 Report Share Posted November 3, 2012 Re: More space news! Two cool new things we can start factoring into designs http://dvice.com/archives/2012/11/living-concrete.php http://dvice.com/archives/2012/11/first-all-carbo.php Quote Link to comment Share on other sites More sharing options...
tkdguy Posted November 7, 2012 Author Report Share Posted November 7, 2012 Re: More space news! Mile-wide asteroid 4 million miles away Lunar crater may help unlock impact secrets Quote Link to comment Share on other sites More sharing options...
tkdguy Posted November 8, 2012 Author Report Share Posted November 8, 2012 Re: More space news! Manned missions to the Moon in the near future? Another planet in its star's habitable zone discovered Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted November 8, 2012 Report Share Posted November 8, 2012 Re: More space news! Manned missions to the Moon in the near future? Another planet in its star's habitable zone discovered ... Orwsum. Orwsum to the max. Quote Link to comment Share on other sites More sharing options...
tkdguy Posted November 15, 2012 Author Report Share Posted November 15, 2012 Re: More space news! Rogue Planet Discovered Planets Orbiting Multiple Stars Have Strange Orbits Space Boat to Titan Quote Link to comment Share on other sites More sharing options...
AmadanNaBriona Posted November 15, 2012 Report Share Posted November 15, 2012 Re: More space news! 'cause the crash et it. Fusion Impulse engine proposed, using deuterium and lithium6 Quote Link to comment Share on other sites More sharing options...
L. Marcus Posted November 15, 2012 Report Share Posted November 15, 2012 Re: More space news! We passed Peak Star Formation eleven billion years ago, and the Universe will only see an additional five percent of stars borne -- ever! Quote Link to comment Share on other sites More sharing options...
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