I will leave this for the aerospace engineers. Back to newtonian basics, we need thrust, a means to stop, and a reason to do that. My view is that space mining is the key. Rare earth's for type-m and type-s asteroids should render an annuity for everyone on earth, especially, those displaced by automation. Call this a planetary trust fund. Yes, I do expect the ai's will want a cut for all the mining and processing done, so yes, we should keep this in mind.
For travel, I could see a plasma drive that gets derived from our search for fusion- but many disagree. Too heavy, etc... On Monday, January 17, 2022 Henrik Ohrstrom <everything-list@googlegroups.com> wrote: You turn the rocket around and as you slow down using BF flashbulbs as you did at takeoff. That's your thruster. Also grav slingshoting can be used to slow down as well as hurry up. If you have not played with Kerbal space program, do so now. It is the best way of getting an understanding of orbital mechanics. Then when you are getting cocky, try children of a dead earth. That one is a mouthful even for NASA personel. /Henrik Den mån 17 jan. 2022 06:58spudboy100 via Everything List <everything-list@googlegroups.com> skrev: Clear back in 1974 the British Interplanetary Society did a paper where the ORION effect would be better fulfilled by Daedalus which would detonate thousands of deuterium-tritium pellets using electron beams. Same principle using many micro-detonations. Orion itself gives me the willies, if only because we'd have to stop it in an Newtonian manner, say when Dyson and company arrived to view Saturn's rings close-up. I am thinking of some means of slowing it down, because at fast speed, the gentle Hohnman Transfer Orbits become unavailable. Thus, we'd need thrusters of some kind to slow her down. Ted Taylor went on to work on solar ponds for providing air conditioning from ice frozen in the winter to provide cooling in the summer. A less grandiose project indeed. For fast interplanetary travel, there needs to be a motivator and yes, your meteorite would do, but mining the Belt seems more sustainable. I am not wedded to any one technology, just one that will work to specification. -----Original Message----- From: John Clark <johnkcl...@gmail.com> To: 'Brent Meeker' via Everything List <everything-list@googlegroups.com> Sent: Sun, Jan 16, 2022 4:18 pm Subject: Re: A gravitational wave rocket On Sun, Jan 16, 2022 at 3:23 PM spudboy100 via Everything List <everything-list@googlegroups.com> wrote: > This surely can't be done anytime soon. My suspicion is that new discoveries > of profound impact will wait until we can build better equipment, as Freeman > Dyson state long ago. I wrote this a few years ago for another list but as the subject of nuclear space propulsion has come up here and you mentioned Freeman Dyson I thought I'd repeat it: == I've been reading a little about an incredible idea taken very seriously in the late 50's and early 60's but today is almost completely forgotten, it was called Project Orion. The idea was to make a spaceship big enough for 150 people and all the equipment they could ever want and blast it into space. They wanted to make it 135 feet in diameter and 160 feet high and they wanted most of that space to be usable by people not wasted on fuel. They figured weight would be no problem, if a crew member wanted to bring along his antique bowling ball collection and his own personal barber chair there would be no objection. The advocates of this approach were not interested in low earth orbit or even the moon, they were certain they could be on Mars by 1965 and Saturn by 1970, the leader of the project was determined to visit Pluto. And they figured all this would cost less than 10% what the Apollo moon project did. You might think that these people must have been a bunch of crackpots, but it's not so. Nobel Prize winners Niels Bohr, Hans Bethe and Harold Urey were all enthusiastic advocates of the idea. Freeman Dyson thought the idea was so brilliant that he took a one year leave of absence from the prestigious Institute of Advanced Study so he could work full time on the project. Yes, there is a catch, Project Orion needed nuclear energy, even worse it needed nuclear bombs. The Orion spacecraft would contain 2000 nuclear bombs, most in the 20 kiloton range, the size of the bomb that destroyed Nagasaki. A bomb in a tank of water would shoot out the back of the ship, when it was100 feet away it would explode, the water would hit a carefully designed 75 ton pusher plate and accelerate the ship. Between the pusher plate and the ship were 50 foot long gas filled shock absorbers to even out the jerk. They wanted everything to be as cheap as possible, so they asked the Coca-Cola company for the blueprints of one of their vending machines, then they scaled it up a little and planned to use it as the mechanism to dispense the bombs. The pusher plate was obviously the most important part of the design. If you explode a powerful bomb near a circular plate of constant thickness it will shatter because of the uneven stresses that build up, but it turns out that if you carefully taper the plate and make certain that the explosion is dead center, the plate will be extraordinarily resistant to damage. A layer on the plate will be vaporized by the heat but if some heavy protective oil is sprayed on it before each use it would be good for 2000 blasts. This beast was tough, if it was properly oriented the Orion Spacecraft could survive a 16 megaton H bomb blast from only two thousand feet away, a fact of more than passing interest to the military. Orion needed lots of radiation shielding to protect the crew, but weight was never an issue so this was no problem. Wernher von Braun though all this was a dumb idea, then he saw a movie of the launch of a one meter working model of Orion that shot 6 carefully timed high explosives chemical bombs out the back of the model, it rose 300 feet into the air in stable controlled flight. Wernher von Braun became a vocal supporter of project Orion. "Hot Rod" - Nuclear Orion spacecraft prototype (1959) They planned to launch Orion from atop eight 250 foot towers in Jackass Flats Nevada. The first bomb would be tiny, just 0.1 kiloton (100 tons of TNT) exploded 100 feet below the craft and 150 feet above the ground, then a new and slightly larger bomb would be spit out the back every second for 50 seconds, the last bomb would be the largest, 20 kilotons, and by then the craft would be out of the atmosphere, the total yield of the 50 bombs would be 200 kilotons. The launch would have been a spectacular sight, it'd make the Space Shuttle look like a bottle rocket. Project Orion was led by Ted Taylor, a mediocre physicist but a very good inventor. Taylor had one unique talent, he has been called by some the best nuclear weapon engineer on planet Earth and the Leonardo da Vinci of nuclear bomb design. Taylor is the man who figured out how a two foot long 200 pound bomb could be made as powerful as the 12 foot long 10 ton World War 2 Nagasaki bomb. The reason the Orion spaceship was so much bigger and faster than anything we have today is that pound for pound such bombs have about a million times as much energy as any chemical rocket fuel. Orion wasn't the only thing Taylor was interested in, he found a way to make a new type of nuclear bomb, one that would produce a highly directional blast. He designed a little one kiloton bomb that could blast a 1000 foot tunnel straight through solid rock, he wanted to build a cheap tunnel between New York and San Francisco and have a supersonic subway 3000 miles long. Considering the big controversy we had when a deep space probe was launched with just a few pounds of non weapon grade Plutonium on it to power the electronics it may seem incredible and irresponsible that anyone would even consider something as environmentally unfriendly as Orion, but we live in a very different world. At the time Orion was under serious study the USA was blowing up one megaton bombs deep under the sea and 300 miles in space and the USSR was blowing up 57 megaton bombs in the atmosphere, Orion seemed and indeed was pretty benign compared to that. It all came to nothing of course, in 1963 the test ban treaty was signed stopping all nuclear explosions in space or the atmosphere making Orion illegal. The project died, but to this day most say it would have worked technologically if not politically. Idea for a science fiction novel: A huge nickel iron asteroid is heading for Earth, it would take a 200,000 megaton bomb to divert it but no existing rocket is nearly powerful enough to deliver such a huge payload to the asteroid. The Earth seems doomed, then our hero remembers Project Orion. John K Clark See what's on my new list at Extropolis pof frt -- 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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAJPayv0c_oUjW_ODMuVy4R6DjkRJzLSmTXYTOoT8rPHV_JoaZQ%40mail.gmail.com . -- 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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/1090542714.509117.1642399128274%40mail.yahoo.com. -- 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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAF0GBngadd4Cir2jnFjsuDRJQiwNg_utDhKLqYSt6RfxJEygFw%40mail.gmail.com. -- 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 everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/336424722.723543.1642486935594%40mail.yahoo.com.
