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Closed Thread (re-hashed)

  1. Dec 13, 2004 #1
    -Prefix .S
    Hey all, Kapton here. I found this thread, closed offcourse. What do people think about this.? Maybe we can get this thread going.?

    The fall of the NERVA program, and the eminent fate of all nuclear engines harnessing reactor based designs;

    The recent demise of the NERVA program is due to final conclusions laid in 1972 (or possibly 73, reports are many, and sketchy on this). The overall energy output of all 20 tried, tested and recorded NTR (Nuclear Thermal Rockets) most harnessing reactor based designs, where existent between 50,000 to 250,000 pounds of thrust.

    The SSME (Space Shuttle Main Engines) harnesses about 412,000pt inside earths atmosphere, about 512,000pt (pounds of thrust) in vacuum, and the combined take off of a 747 commercial airliner is about 220,000pt.

    This led to costly engine manufacturing, extreme environmental-health risks and wasted engineers, developers and companies time and money. The project cost about 1.5 billion dollars to be exact, that's about 7 billion dollars today that was spent on the NERVA project. The process of such designs, is a direct port of technology from nuclear reactors used in today's commercial power plants, nuclear subs and other energy manufacturing installations. The idea of using elements such as Hydrogen in today’s NTR (which contain nuclear reactors) clearly illustrates the complete and utter un-understanding for nuclear technology which has lead to teams of engineers, specifically those inside NASA's Glenn Research Center, to depict future concepts to be in equivalent of about 15,000pt due to cost cutting and resizing issues for premium t\w ratio (thrust to weight) requirements.

    This 15,000pt bench mark for a new NTR is being worked on at this very point in time in both the NASA Glenn and NASA Marshall Space Flight Centers in the U.S for purposes to create the 'Next Gen' launch systems for planetary missions. These missions are the future for astronaut manned space flights. The orbiter's OMS (which is a secondary propulsion system, Orbiter Maneuvering System) produces in total of two engines, 12,000pt.

    Because of the technical parameters of today's NTR, the largest down-fault seems to emanate from reactors and their part in nuclear engineering today. Using a reactor, uranium micro-fissions, which can produce thermal and other pressure properties that act out on light-weight fuels (accelerants) such as hydrogen, causing the fuel itself to super-heat, expand and increase in velocity – thus in energy output, which is directed through the nozzle. The very purpose of nuclear physics, reasons why the nuclear bomb was first intended to be built, where to use the very energy from 'direct nuclear fission + fusion' (the expanding ionization energy derived from neutron bombardment and/or lighter nuclei fuse) which underlies the very properties and purposes of nuclear physics today. Nuclear physics for space exploration is specifically intended, from the very beginning to today, to be beneficial in primarily - gargantuan energy output. (massive energy outputs)

    These feeble attempts in reactor based NTR show no advancement and lead nuclear propulsion into strange and unfamiliar places; Take into account this new NTR. To get this engine to operate, massive alterations where made to its design. It is now 1/16th the size of a common bench mark solid core NERVA, with about 1\18th - 1\19th % in total energy output of the original design, still has extreme environmental risks but is cost effective, this design spawning into a small 15,000pt nuclear thermal rocket. With this new NTR all advancements that where once made are now lost. Actually no advancements where ever made, the energy output of the NERVA program rockets where less than a chemical rocket with higher thermal, cost, environmental and expendability factors. So what actual advancements have been made with NTR's? None...
    To even consider using NTR's in the future, costs have to be cut, weight and size has to be met (mainly for t\w ratio problems), environmental factors play a large part and the most elusive effort becomes lost in this equation - total energetic thrust output. So this is the truth about NTR's that use nuclear reactors as sources for power advancement.

    What the hell is the point of 15,000pt in space, hasn’t anyone heard of momentum? The latest mission to mars (MER, Mars Exploration Rovers) showcases momentum and its balance in orbital mechanics, astrophysics and spaceflight dynamics quite well. The MER launch vehicle consisted of a three staged rocket.
    - The first stage was in assistance for primarily placing the rover just inside of LEO (Low Earth Orbit).
    - The second stage was the primary propulsion stage. It consisted of a small Aerojet AJ10 - 118K engine (using A-50 and N204 for fuels) which launched the third stage (and rover) into LEO. The second stage engine is restartable and fired twice. Once in LEO the vehicle re-aligned with mars and then the final and second burn took place in LEO which sent the rover in the correct alignment-direction and sufficient velocity to reach mars. The third stage was a small attitude thruster engine, available to make six quick direction changes primarily to put the rover back on a correct flight path by changing axial alignments. The primary propulsion engine which supported the vehicle to reach mars at a high enough velocity was the small Aerojet engine, thus coupled with the first two burns was assisted only by gradual loss and gain of momentum.

    If we take this flight plan into account, we can reciprocate most of the results for NTR performance to other planets.
    What NTR's should and need to have in account, is using nuclear technology for large energy outputs instead of small outputs and continuity. Granted, an engine with a 15,000pt output is small, but the ISP for this NTR is still very high. The ISP meaning specific impulse or efficiency, is about 900 (or so) which seems to be a great deal over other chemical combinations such as LH2 which is 453 is vacuum, Aerozine 50 which is 320 in vacuum, and Hydrazine which is 300 in vacuum (all ISP ratings rounded). However, don't be fooled by this few hundred rating increase.

    An engine with less energy output must maintain a constant velocity for longer to circum gravity. Thus, the engine must be -on- for extended periods of time, which causes the NTR to become expendable due to irreplaceable loss of nuclear fuel, thermal damage inflicted on the reactor, combustion chamber and internal components, eventual loss of hydrogen propellant and all factors which develop into a completely useless engine structure. All NERVA designs so far are fully expendable.

    Meanwhile the usage of LH2 (Liquid Hydrogen) for space flight will render the mission, vehicle, engine and the NTR specified project completely useless. I have previously worked with LH2 for theoretically planned interplanetary missions (primarily due to high ISP factors) and found that all efforts to use the fuel for spaceflight where in vein. LH2 cannot survive in liquidized form for an interplanetary mission. Liquid Hydrogen must be kept well below boil off point to remain in a liquid state, which is about - 200 degrees Celsius (- 400 degrees Fahrenheit). Even with a state of the art cooling system, this is not possible. Direct sunlight on a mission will cause the tank to overheat (maintaining axial changes away from direct sunlight for temperature drops is improbable for the duration of a mission.) LH2 has an extremely fine molecular structure, permitting it to breach the finest of cracks, holes and even most materials. The shuttle's ET (External Tank) must be 'topped up' continuously just until ignition (launch) to provide protection against boil-off from the Liquid Hydrogen forming into useless gas. LH2 stored for an extended period inside a tank will eventually boil-off into gas but before then it will reform into a solid state, more specifically forming large quantities of frozen ice sickles (a counter agent for this on the outside of the ET is polyisocyanurate foam.) Landing such a vehicle that contains an NTR (harnessing a reactor) on a planet, i.e. mars, would cause intolerable heat stress on the LH2 due to heat-trapping CO2 (Carbon Dioxide) found inside the atmosphere. The very fabric of space-time (referred to from general theory \ Einstein) - - (specifying in this instant, a geometrically defined area of space), say between mars and earth, pertains quiet low temperatures, substantially cold, however would still cause boil-off. LH2 is an extremely difficult fuel to work with in terms for space flight missions and should not, and probably will not, be implemented in future space flight designs for these reasons - even though now many engineers see it to be the way for NTR development.

    Taking all of these parameters into account, a mission using this future depicted NTR is believed (and calculated by NASA Glenn engineers) to reach mars in about 4 months - obviously on only a type -I interplanetary trajectory. Return mission to earth are calculated at about 8 months travel time. Threats are posed here for enviromental damage, physically to muscle and bone structures, and phycologically for astronauts. (Grav systems could be emplyed, however axial rotating modules are highly dubious)
    Last edited: Dec 13, 2004
  2. jcsd
  3. Dec 14, 2004 #2
    just looking at that hurts my head
  4. Dec 14, 2004 #3


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    Staff Emeritus
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    Gold Member

    nice try, u235.

    I saw when you posted and deleted this the day after you were banned for being a pest and wasting my time.

    You are not going to be allowed to run rampant through my forums.

    Next time you pull crap like this, I'll make a motion for an IP ban.
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