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#1
May 7th 14, 12:38 PM
posted to sci.space.policy
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Short Mars travel times now possible through plasma propulsion.
Mars orbits 228.5 million km away from the Sun. That's 1.524 AU, which means its year is 1.524^(3/2) according to Kepler, or 1.88 years.
Earth orbits 150.0 million km away from the Sun. The synodic period is 1/Ps = 1/Pe - 1/Pmars = 1/Ps = 1/1 - 1/1.88 -- Ps = 2.14 years So, every 2.14 years we go through this cycle from 228.5 - 150.0 =78.5 million km. to 228.5 + 150.0 = 378.5 million km Now, humans can withstand 1.5 gees indefinitely. Now the distance something undergoing constant acceleration travels in a given time is given by D = 1/2 * a * t^2 solving for t t = sqrt(2 * D / a) So, if we boost half the distance speeding up, and then boost half the distance slowing down, t is; t = 2 * sqrt(D/a) This gives the result in seconds if D is in meters and a is in meters/sec2. So, every 13 days we have for the first half of the synodic period 78.5 40.6 108.5 47.7 138.5 53.9 168.5 59.5 198.5 64.5 228.5 69.2 258.5 73.6 288.5 77.8 318.5 81.7 348.5 85.5 378.5 89.1 and then the same list in reverse for the remainder of the synodic period. So, we can see if we can boost at 1.5 gees for the entire trip, we can make the trip between 41 hours and 90 hours. Two to four days. How to do it? With an all optical system - known as the Photonic Thruster. http://ykbcorp.com/downloads/Bae_pho...ulation..pd f Conjugate Optical mirrors when used to recycle photons in a laser driven light sail, reduces power demand for that sail. Producing laser energy in space using solar pumped lasers, requires no fuel or propellant. Recycling the photons 20,000 times produces 0.1 milli-Newtons per watt, with no expenditure of propellant. Consider a 100 GW laser beam produced in GEO using a 10.6 km diameter mirror illuminating a 265 meter diameter thin disk laser array, shining through a 265 meter diameter conjugate mirror forms a spot less than 1 meter in diameter. Recycled 20,000 times in a launching telescope, the 100 GW beams rises in power to 20 TW circulating power! This produces 1,000 tonnes of thrust at the conjugate mirror on the spacecraft, lifting 680 tonnes at 1.5 gees straight up! A mirror that is 99.999% reflective covering 1000 m2 of area rises to 648K in vacuum. As the ship leaves Earth, the beam switches from he launch centre at Earth, to the station on orbit, as shown in Dr. Bae's paper. A 10 km recirculating mirror in space beams energy up to 189 million km away producing a spot size only 23 meters in diameter. A conjugate mirror this size produces a spot 10 km in diameter, on the way back. Of course, objects closer together have higher resolutions. A similar power satellite operating on orbit around Mars, powers the conjugate optical mirror slowing the spacecraft, as it traverses the second half of its journey. The circulating energy can be sent to the Mars station and continue to be used. The circulating energy can also be used to launch another spacecraft to Mars, or used, to slow a returning spacecraft traversing nearly the same path (but not exactly the same path) in the opposite direction. The same technology that predicts the motion of the accelerating spacecraft and accounts for the time delay of up to 20 minutes, without any loss of accuracy, can also redirect circulating energy in the beam. The spacecraft consists of a shell covered with highly reflective mirrors. A 23 m diameter disk has an area of 415.7 square meters. 20 trillion watts of circulating power translates to 48.2 GW/m2. A mirror that is 99.99999% reflective absorbs 482 W/m2. Insulated on the back side, and emitting thermal radiation in the front side in vacuum. Thus, according to Stephan Boltzman, T = (W/rho)^(1/4) = (482/5.67e-8)^.25 = 303.6 Room temperature. A birefringent mirror can reflect a laser beam with almost perfect efficiency. http://gemini.cems.umn.edu/research/..._shows/gbo.pdf The only propulsive capability that's required on board is attitude control and guidance. This translates to 0.5 km/sec delta vee. With a hydrogen/oxygen rocket, this is a propellant fraction of only 1 - 1/exp(0.5/4.2) = 0.1122 11.22% and with a structure fraction of 18% - we have a payload fraction of over 70% !!! So, our 100 GW beam, with our highly reflective conjugate optical mirrors, produces 1,020 tonnes of lift, carrying 680 tonne spacecraft at 1.5 gees constant throughout its trip. Of this 476 tonnes is useful load. 122.4 tonnes is inert mass. 76.3 tonnes is hydrogen and oxygen. Power of course is supplied by photovoltaic conversion of the incident laser beam! Emergency power is available from the stored hydrogen and oxygen. Water is fully recycled on board, however, it can be used in a pinch to recharge propellants. To give you an idea of what 680 tonnes can be, consider the following yacht; http://www.superyachts.com/yacht-charter/air-1683/ It has a crew of 24 and carries 17 guests on cruises lasting up to two weeks. Of course in two weeks you can go to Mars and back at 1.5 gees, and spend a week to a week and a half on planet, and around it, visiting Diemos and Phobos. Now these cruises are about 1 million euros per week, so a two week tour would be 2 million euros - and this ship stays busy all throughout the year. I've got to believe that a spacecraft built to this standard, and running back and forth from Mars, would also be busy, even at 10 million euros per guest - or 140 million euros per trip. With two weeks per trip, and two weeks in dry dock, we have the potential for 1.82 billion euro per year - just for base fees. Then you've got tips, and incidentals. A Moet on Mars has got to cost many times the 300 euros you pay in Paris. So, with an orbiting power station at Mars, and another at Earth, with launch facilities on each world, you'll need four circulating ships. That is, one going out, as another is coming back, and while they're in dry dock, you want to have another flying. So four minimum, and a fifth one, a specially built emergency job. Just to make folks feel better. Let's say six, one on Earth one on Mars... ready to pick up the crew from a broken ship. Each ship is going to make 2.5 billion euro - and so four active ships - 10 billion euro a year. Now, these ships are robust, not much to go wrong, especially in this day and age of MEMS technology. A 27 year working life. Okay, the infrastructure earns 10 billion euro a year. Discounted at 6.25% per year over 27 years means that the day it starts up the two satellites, and six ships are worth 128 billion. Now, development time is five years. So, we could spend 54.72 billion on this infrastructure pay 41.4% annualized compounded return to investors during the 5 year build out, and pay 6.25% annualized compounded return to the financiers who paid out the investors once the ships were operating. In billions euros Return Risk Year e14.74 e2.61 1 e20.85 e5.21 2 e29.48 e10.42 3 e41.69 e20.85 4 $22.11 $15.63 5 $128.87 $54.72 Total The big ticket item though, for anyone who's developed this supply chain, is selling high end homes on Mars! (along with personal space yachts!) That's because of the 728 guests that visit Mars every year, 3 or 4 of them will have the wherewithal, and interest, in building a home on Mars, far from the maddening crowd! The finest properties, from around the world, (and beyond); https://www.youtube.com/watch?v=0V8ues_FH6c We know Mars https://www.youtube.com/watch?v=7V_uRV0nkI0 We can see that 4 homes at 250 million euros another 1 billion euros a year in construction, but then there's the 200 million per year each family will spend whilst on Mars. So, each year, this grows, and by the fifth year, the community earns more than the building. Also, with two service and support persons per buyer, we have a secondary population growing far faster than the primary (from an economic view) population. After twenty years, the economic sector is totally independent on Earth. Mars is changing - fast! https://www.youtube.com/watch?v=LKtczktcB08 
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#2
May 7th 14, 06:05 PM
posted to sci.space.policy
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Short Mars travel times now possible through plasma propulsion.
OK. But Nevada and Tibet would be easier to develop than Mars.
On Mars the bulk of the time, the people of the colony would be underground, IMO. Sheltering from radiation and shrapnel of incoming meteorites and operating local remotely operated "avatars". Food production would be a challenge on Mars. Justing getting a working soil would take time. Imagine shipping compost to Mars! Besides glory and a hedge on the bets of the survival of the species, what will Mars provide to the top 1 percent of the 1 percent? What will it provide to the one percent? What will it provide to masses? A tax on oxygen in the colony? Nitrogen the new gold for Mars? And back home what? Knowledge? Lithium? What?
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#3
May 7th 14, 07:29 PM
posted to sci.space.policy
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Short Mars travel times now possible through plasma propulsion.
Wrong Stuff wrote:
Justing getting a working soil would take time. Imagine shipping compost to Mars! Why ship compost - just use the corpses of the previous set of colonists... rick -- No need to believe in either side, or any side. There is no cause. There's only yourself. The belief is in your own precision. - Joubert these opinions are mine, all mine; HP might not want them anyway...  feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
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#4
May 8th 14, 02:06 AM
posted to sci.space.policy
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Short Mars travel times now possible through plasma propulsion.
"Rick Jones" wrote in message ...
Wrong Stuff wrote: Justing getting a working soil would take time. Imagine shipping compost to Mars! Why ship compost - just use the corpses of the previous set of colonists... I think you'd need a LOT of former colonists. ;-) rick -- * I promise I will format my posts properly in the future. * Windows Live Mail just can't quote! Luckily, I have found this: * http://www.dusko-lolic.from.hr/wlmquote/
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#6
May 8th 14, 03:23 AM
posted to sci.space.policy
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Short Mars travel times now possible through plasma propulsion.
Aeroponics has solved the problem of food in space. (and on Earth)
http://www.nss.org/settlement/Coloni...es_chap09.html This is 1970s tech. Its only because of a capital strike among the oligarchy that controls our banking system that these things aren't done. Their attitude is if you feed the rabble, you'll get more of them. And worse, they'll actually start thinking seriously they have rights. None of that is in their interest. So, no aeroponics and no direct synthesis of amino acids to feed cell cultures that get assembled in 3D printers into anything you like. That ain't happening any time soon, even though a modest investment would make such things as common as HDTVs staring out at everyone connected by wireless broadband to AI clouds to do pre-crime, which they've explained to you already in sci-fi films. The oligarchy gets what it wants because its paying the bills and it doesn't want you to live. Why? Because as one oligarch said, too many people are using too much stuff. http://en.wikipedia.org/wiki/Amino_acid_synthesis http://www.futurefood.org/in-vitro-meat/index_en.php http://techcrunch.com/2014/03/27/foodini/ https://www.youtube.com/watch?v=DSlB1nW4S54 Year People lbs/acre lbs/per acres technology 1800 375 333 1,450 1,633 Irrigation 1850 750 1,000 1,500 1,125 Mechanization 1900 1,500 3,000 1,550 775 Fertilizer 1950 3,000 9,000 1,600 534 Automation 2000 6,000 27,000 1,650 367 Aeroponics 2050 9,000 81,000* 1,700 189 Cell Culture *NOTE: Area of solar panels to drive synthetic amino acid production Also, population growth mediates with high income levels. We were derailed from this development arc by the aforementioned capital strike, which caused the current artificial scarcity in food. Aeroponics already has the capacity to produce over 52,000 lbs of food per acre. The current 7.12 billion persons in the world eating 1,650 lbs of food and meat per year require 226 million acres of aeroponic farms. At $1 per pound for food, we could spend as much at $697,000 per acre to build aeroponic farms. Not that much is needed, but it just goes to show what's possible. According to BLS there are 749,000 people who grow, harvest, process and deliver food to 319,000,000 Americans. That's 1 in 425. With aeroponic techniques this drops to 1 in 1,500. This using technology developed in the 1970s! That's 4.75 million farm workers world wide producing 2.473 million pounds of food each. Adding $0.10 to the cost of each pound of food, that's $1.10 per pound - on average - the farmers earn $247,300 per year. Bankers who invest as much as $697,000 per acre to grow food in this way, earn 6..25% per year - for the life time of the equipment. People get fed for $1.10 per pound - or $34.90 per week - for any food they like. The Stanford Torus studies which I outline above assumed an upper middle class lifestyle. The 320 acres supporting 10,000 inhabitants not only produce all the food locally, but also medicines and fibre too! Of course, costs drop to even lower levels and land use to nearly nothing, when we consider the direct synthesis of food. https://www.youtube.com/watch?v=DSlB1nW4S54 Apples are 94% water. Beef is 70% water. Food on average is 82% water. So, that 1,650 lbs per year turns into 287 lbs of fats, oils, amino-acids, and so forth. Cell proliferation rates are such that they can double in number, under the right conditions, in as little as 10 minutes. Thus, a device that makes 12.6 ounces of fats oils and amino acids synthesized directly from CO2, H2O, and other common materials, along with half a gallon of water per day, to feed half an ounce of cells in a microscopic culture, that produce 4.5 pounds of food product per day. These cells are then assembled in a 3D printer to make any desired food product. To maintain variety, a quarter pound of cells are kept, to provide an array of flavours and nutrients. The entire system, including chemical synthesis is the size of a toaster oven.
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#7
May 8th 14, 10:26 PM
posted to sci.space.policy
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Short Mars travel times now possible through plasma propulsion.
On Wednesday, May 7, 2014 11:29:39 AM UTC-7, Rick Jones wrote:
Wrong Stuff wrote: Justing getting a working soil would take time. Imagine shipping compost to Mars! Why ship compost - just use the corpses of the previous set of colonists... rick Freeze dried compost used as shielding on the way out to Mars and prepared for a semi-hard impact.
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#8
May 21st 14, 03:37 PM
posted to sci.space.policy
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Short Mars travel times now possible through plasma propulsion.
Circumference of the Earth is 40,000 km. To fly to the antipodes traverses 20,000 km. That's as far as you can travel on Earth. Accelerating at 2 gees for a distance of 10,000 km requires
D = 1/2 * a * t^2 -- t = sqrt(2*D/a) = 1,009.8 seconds = 16 min 49.8 sec Double this to account for slowing at 2 gees - 33 min 39.6 sec Top speed is v = a * t = 2 * 9.807 * 1,009.8 = 19.8 km/sec At this speed following the curvature of the Earth means that the vehicle is feeling a force of 5.28 gees outward! Total gee force is 5.65 gees. Of course, travel at 13.7 km/sec means outward centripetal force is 3 gees at 1 Earth radii. Which means you have to apply 2 gees outward. This occurs with horizontal acceleration tangent to Earth's surface of 2 gees after 11 minutes 35.7 seconds. So, it takes 2,772.3 km to accelerate to this speed, and another 2,772.3 km to slow down to zero speed - 9,544.6 km in all. Thus, to fly to the antipodes another 10,455.4 km is travelled at 13.7 km/sec boosting toward the Earth's centre at 2 gees for another 12 minutes 44 seconds. 36 minutes overall from start to finish. km minutes 10 0.75 20 1.06 50 1.68 100 2.38 200 3.37 500 5.32 1000 7.53 2000 10.64 5000 16.83 Average distance travelled is 500 km, with 5.32 minute boost at 2 gee. Average passenger loading 2 passengers per trip. 180 people per day is served by one machine. A total of 40 million vehicles provide on demand flight service world wide for 7.12 billion. A 1,500 kg vehicle propelled by a 7 km/sec exhaust from a fusion powered jet, requires 103 MW of power. This uses 1/8 gram of fusion fuel per flight. Each person uses 1/5th gram per day - 3 trips 2 pass per trip. This totals 1,335 tonnes per day. This is a total of 4.1 quadrillion watts overall. Kardashev score K=0.97
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