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Space090912
A space pier using reusable rockets may be more feasible than a space elevator for providing cheaper access to geosynchronous orbit. While a space elevator faces serious material challenges due to its length, a space pier concept using 100km towers in space could utilize less exotic materials and avoid the difficulties of an elevator reaching from the ground to space.
Space090912
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- 13. Space Pier insteadof Space Elevator Reuseable Saturn Heavy would have cheaper cost to GEO than space elevator Serious material issues for earth space elevator 100 km towers in space pier can use much less exotic material
Editor's Notes
- #3 The objectives of the Robotic Asteroid Prospector (RAP) project are to examine and evaluate the feasibility of asteroid mining in terms of means, methods, and systems. This study decomposes the challenge of asteroid mining into four key efforts:1. Mission design, including trajectory and logistics from an Earth-Moon Lagrange Point (EMLP) to the asteroid and return to that EMLP,2. Spacecraft design including propulsion and Mission operations,3. Mining technology for microgravity and vacuum operations, and4. How these efforts can add up to a business case for asteroid miningSCOPE:The focus is to design the Robotic Asteroid Prospector (RAP) spacecraft and missions so that the spacecraft, mission architecture, extraction, and analysis technologies are “mining-forward.” The system will be scalable from robotic to human-tended operations for large-scale extraction and beneficiation. RAP will serve as a testbed for the later industrial-scale mining missions, including human-operated missions. For Phase 1, this proposal describes a prototype RAP spacecraft and mission design trade study. Phase 2 will involve prototype hardware development and operational simulation.APPROACH:The Project’s approach addresses six points:1. Abundant and accessible minerals in the Type M asteroids,2. Market demand on Earth and the business case asteroid mining,3. Assessment of the five Lagrange Points as a fueling depot and staging platform.4. Asteroid types, including M-Type for metals and C-Type for water, their orbits, and trajectories,5. Robotic extraction and processing, and6. Robotic spacecraft leading to human missions ASSUMPTIONS:RAP assumes these future capabilities:* A Venus orbit NEO observatory will identify and characterize more asteroids in general and metallic M-Types in specific.* Commercial transport for crew and cargo will be available to Earth-Moon Lagrange Points (EMLP) and return to Earth.* An EMLP fueling depot and mission staging platform sustained by commercial “freighters” and “tankers” from which to fuel and deploy the RAP on its mission.
- #4 The future of manned space exploration and development of space depends critically on the creation of a dramatically more proficient propulsion architecture for in-space transportation. A very persuasive reason for investigating the applicability of nuclear power in rockets is the vast energy density gain of nuclear fuel when compared to chemical combustion energy. Current nuclear fusion efforts have focused on the generation of electric grid power and are wholly inappropriate for space transportation as the application of a reactor based fusion-electric system creates a colossal mass and heat rejection problem for space application. The Fusion Driven rocket (FDR) represents a revolutionary approach to fusion propulsion where the power source releases its energy directly into the propellant, not requiring conversion to electricity. It employs a solid lithium propellant that requires no significant tankage mass. The propellant is rapidly heated and accelerated to high exhaust velocity (over 30 km/s), while having no significant physical interaction with the spacecraft thereby avoiding damage to the rocket and limiting both the thermal heat load and radiator mass. In addition, it is believed that the FDR can be realized with little extrapolation from currently existing technology, at high specific power (about 1 kW/kg), at a reasonable mass scale (less than 100 mt), and therefore cost. If realized, it would not only enable manned interplanetary space travel, it would allow it to become common place.
- #5 Fusions Assumption:• Ionization cost is 75 MJ/kg• Coupling Efficiency to liner is 50%• Thrust conversation ~ 90%• Realistic liner mass are 0.28 kg to 0.41 kg• Corresponds to a Gain of 50 to 500• Ignition Factor of 5• Safety margin of 2: GF =GF(calc.)/2Mission Assumptions:• Mass of Payload= 61 mT• Habitat 31 mT• Aeroshell 16 mT• Descent System 14 mT• Specific Mass of capacitors ~ 1 J/kg• Specific Mass of Solar Electric Panels 200 W/kg• Tankage fraction of 10% (tanks, structure, radiator, etc.)• Payload mass fraction =Play load Mass• System Specific Mass = Dry Mass/SEP (kg/kW)• Analysis for single transit optimal transit to Mars• Full propulsive braking for Mar Capture - no aerobraking
- #6 The key to achieving all this stems from research at MSNW on the magnetically driven implosion of metal foils onto a magnetized plasma target to obtain fusion conditions. A logical extension of this work leads to a method that utilizes these metal shells (or liners) to not only achieve fusion conditions, but to serve as the propellant as well. Several low-mass, magnetically-driven metal liners are inductively driven to converge radially and axially and form a thick blanket surrounding the target plasmoid and compress the plasmoid to fusion conditions. Virtually all of the radiant, neutron and particle energy from the plasma is absorbed by the encapsulating, metal blanket thereby isolating the spacecraft from the fusion process and eliminating the need for large radiator mass. This energy, in addition to the intense Ohmic heating at peak magnetic field compression, is adequate to vaporize and ionize the metal blanket. The expansion of this hot, ionized metal propellant through a magnetically insulated nozzle produces high thrust at the optimal Isp. The energy from the fusion process, is thus utilized at very high efficiency. Expanding on the results from the phase I effort, phase II will focus on achieving three key criteria for the Fusion Driven Rocket to move forward for technological development:1. the physics of the FDR must be fully understood and validated,2. the design and technology development for the FDR required for its implementation in space must be fully characterized, and3. an in-depth analysis of the rocket design and spacecraft integration as well as mission architectures enabled by the FDR need to be performed. Fulfilling these three elements form the major tasks to be completed in the proposed Phase II study. A subscale, laboratory liner compression test facility will be assembled with sufficient liner kinetic energy (about 0.5 MJ) to reach fusion breakeven conditions. Initial studies of liner convergence will be followed by validation tests of liner compression of a magnetized plasma to fusion conditions. A complete characterization of both the FDR and spacecraft will be performed and will include conceptual descriptions, drawings, costing and TRL assessment of all subsystems. The Mission Design Architecture analysis will examine a wide range of mission architectures and destination for which this fusion propulsion system would be enabling or critical. In particular a rapid, single launch manned Mars mission will be detailed.
- #7 http://nextbigfuture.com/2010/12/fusion-plasmoid-space-propulsion.htmlhttp://nextbigfuture.com/2012/03/nuclear-propulsion-through-direct.html
- #8 SpiderFab: Process for On-Orbit Construction of Kilometer-Scale Apertureshttp://www.nasa.gov/offices/oct/early_stage_innovation/niac/2012_phase_I_fellows_hoyt_spiderfab.htmlCurrently, a significant fraction of the engineering cost and launch mass of space systems is required exclusively to enable the system to survive launch. This is particularly true for systems with physically large components, such as antennas, booms, and panels, which must be designed to stow for launch and then reliably deploy on orbit. Furthermore, the sizes of apertures and spacecraft structures are limited by the requirement to stow them within available launch fairings. Deployable structures and inflatable/rigidizable components have enabled construction of systems with scales of several dozen meters, but their packing efficiency is not sufficient to enable scaling to the kilometer-size baselines desired for applications such as long-baseline interferometry and sparse aperture sensing.We propose to develop a process for automated on-orbit construction of very large structures and multifunctional components. The foundation of this process is a novel additive manufacturing technique called ‘SpiderFab’, which combines the techniques of fused deposition modeling (FDM) with methods derived from automated composite layup to enable rapid construction of very large, very high-strength -per-mass, lattice-like structures combining both compressive and tensile elements. This technique can integrate both high-strength structural materials and conducting materials to enable construction of multifunctional space system components such as antennas. The SpiderFab technique enables the constituent materials for a space structure to be launched in an extremely compact form, approaching perfect packing efficiencies, and processed on-orbit to form structures optimized for the micro-gee space environment, rather than launch environments. The method can also create structures with 2nd and higher orders of hierarchy, such as a ‘truss-of-trusses’, achieving 30X mass reductions over the 1st order hierarchy structures used in most space applications. This approach can therefore enable deployment of antenna reflectors, phased array antennas, solar panels, and radiators with characteristic sizes one to two orders of magnitude larger than current state-of-the-art deployable-structure technologies can fit within available launch shrouds.
- #9 http://www.nasa.gov/offices/oct/early_stage_innovation/niac/2012_phaseII_fellows_miller.htmlIn our NIAC Phase I study, awarded September 2011, the MIT Space Systems Lab (MIT SSL) began investigating a new structural and mechanical technique aimed at reducing the mass and increasing the stowed-to-deployed ratio of spacecraft systems. This technique uses the magnetic fields from current passing through coils of high temperature superconductors (HTSs) to support spacecraft structures and deploy them to operational configurations from their positions as stowed inside a launch vehicle fairing. The chief limiting factor in spacecraft design today is the prohibitively large launch cost per unit mass. Therefore, the reduction of spacecraft mass has been a primary design driver for the last several decades. The traditional approach to the reduction of spacecraft mass is the optimization of actuators and structures to use the minimum material required for support, deployment, and interconnection. Isogrid panels, aluminum or composites, and gas-filled inflatable beams all reduce the mass of material necessary to build a truss or otherwise apply surface forces to a spacecraft structure. We instead look at using electromagnetic body forces generated by HTSs to reduce the need for material, load bearing support, and standoffs on spacecraft by maintaining spacing, stability, and position of elements with respect to one another.Spiderfab was the other NASA NIAC project for building bigger in space. Spiderfab would use additive manufacturing. There was also contour crafting (cementjet printer manufacturing for building on the moon, planets and asteroids.
- #10 NanoTHOR: Low-Cost Launch of Nanosatellites to Deep SpaceTo enable frequent, low-cost opportunities to deliver nanosatellites to destinations beyond Earth orbit, TUI proposes to develop the “Nanosatellite Tethered High-Orbit Release” (NanoTHOR) module. The NanoTHOR module will enable multiple nanosatellites carried as secondary payloads on upper stages launched into GTO to be injected into Earth-escape trajectories by scavenging orbital momentum and propellant from the upper stage. The NanoTHOR module will utilize a lightweight, re-usable tether to transfer momentum from the rocket stage to the nanosatellite. The use of a rotating tether “multiplies” the rocket’s delta-V by the mass ratio of the stage to the nanosat, enabling it to provide both very-high specific impulse propulsion competitive with the best EP thrusters AND short transfer times competitive with chemical rockets. The tether also enables the stage’s orbital momentum to be converted to tether rotational momentum to increase the nanosat toss velocity. After completing its mission, the tether can be de-orbited within one orbit period to eliminate collision or debris risks. The nanoTHOR module will provide a low-cost, low-mass means to enable nanosatellites to be launched as ride-share payloads on GEO satellite missions and then delivered to deep-space trajectories. It will therefore enable NASA to affordably launch flotillas of low-cost nanosatellites into heliocentric orbits to conduct searches for NEOs, to study potential targets for manned exploration of asteroids, to provide ‘nowcasting’ of solar weather conditions, and to serve as communications relays for manned and unmanned missions beyond Earth orbit.
- #11 Small, light-weight and low-cost missions will become increasingly important to NASA's exploration goals for our solar system. Ideally teams of dozens or even hundreds of small, collapsable robots, weighing only a few kilograms a piece, will be conveniently packed during launch and would reliably separate and unpack at their destination. Such teams will allow rapid, reliable in-situ exploration of hazardous destination such as Titan, where imprecise terrain knowledge and unstable precipitation cycles make single-robot exploration problematic. Unfortunately landing many lightweight conventional robots is difficult with conventional technology. Current robot designs are delicate, requiring combinations of devices such as parachutes, retrorockets and impact balloons to minimize impact forces and to place a robot in a proper orientation. Instead we propose to develop a radically different robot based on a "tensegrity" built purely upon tensile and compression elements. These robots can be light-weight, absorb strong impacts, are redundant against single-point failures, can recover from different landing orientations and are easy to collapse and uncollapse. We believe tensegrity robot technology can play a critical role in future planetary exploration.http://www.nasa.gov/offices/oct/early_stage_innovation/niac/2012_phase_I_fellows_agogino.html
- #12 NASA - Water Walls (WW) takes an approach to providing a life support system that is biologically and chemically passive, using mechanical systems only for plumbing to pump fluids such as gray water from the source to the point of processing. The core processing technology of Water Walls is FORWARD OSMOSIS (FO). Each cell of the WW system consists of a polyethylene bag or tank with one or more FO membranes to provide the chemical processing of waste. WW provides four principal functions of processing cells in four different types plus the common function of radiation shielding: 1. Gray water processing for urine and wash water,2. Black water processing for solid waste,3. Air processing for CO2 removal and O2 revitalization,4. Food growth using green algae, and5. Provide radiation protection to the crew habitat (all cells).
- #13 With its all-sky infrared survey, NASA's Wide-field Infrared Survey Explorer, or WISE, has identified millions of quasar candidates. Image credit: NASA/JPL-Caltech/UCLA Images from the telescope have revealed millions of dusty black hole candidates across the universe and about 1,000 even dustier objects thought to be among the brightest galaxies ever found. These powerful galaxies, which burn brightly with infrared light, are nicknamed hot DOGs."WISE has exposed a menagerie of hidden objects," said HashimaHasan, WISE program scientist at NASA Headquarters in Washington. "We've found an asteroid dancing ahead of Earth in its orbit, the coldest star-like orbs known and now, supermassive black holes and galaxies hiding behind cloaks of dust.”WISE scanned the whole sky twice in infrared light, completing its survey in early 2011. Like night-vision goggles probing the dark, the telescope captured millions of images of the sky. All the data from the mission have been released publicly, allowing astronomers to dig in and make new discoveries.The latest findings are helping astronomers better understand how galaxies and the behemoth black holes at their centers grow and evolve together. For example, the giant black hole at the center of our Milky Way galaxy, called Sagittarius A*, has 4 million times the mass of our sun and has gone through periodic feeding frenzies where material falls towards the black hole, heats up and irradiates its surroundings. Bigger central black holes, up to a billion times the mass of our sun, may even shut down star formation in galaxies.In one study, astronomers used WISE to identify about 2.5 million actively feeding supermassive black holes across the full sky, stretching back to distances more than 10 billion light-years away. About two-thirds of these objects never had been detected before because dust blocks their visible light. WISE easily sees these monsters because their powerful, accreting black holes warm the dust, causing it to glow in infrared light.
- #14 he Earth based space elevator is 90,000 miles long. It goes past geosynchronous orbit. It is double the distance to geosynchronous at least. A space pier uses towers that are 100 kilometers tall and can use 5 GPa material. A space pier would be 1300 times shorter than a space elevator and can use materials that are 10 times weaker.A space pier seems to strain credulity for some but is far easier to build than a space elevator. Very tall inflatable towers are under development.
- #15 Another huge solar filament and storm on August 31ASA spacecraft watching the sun have captured jaw-dropping pictures and video of a giant filament of super-hot plasma reaching up from the star's surface and erupting into space.The filament was made of solar material that was ejected from the sun during an intense solar storm on Aug. 31. Flares are caused by increased magnetic activity on the surface of our star, and are becoming more common as the sun approaches a phase of peak activity in 2013.