 SPACECRAFT STRUCTURE MAIN SKELETAL STRUCTUREThe structural system is the main backbone of the Lightcraft. All of the various components play an integral role in providing sound structural support and safety to the crewmembers and payload. The Lightcraft is an inflated vehicle capable of attaining supersonic speeds while in an atmosphere as well as high-velocity space flight. The primary framework of the lightcraft is constructed around a toroidal pressure vessel at the lightcraft's rim. The main hull section, shaped like a shallow dome, is supported from this structure. The toroidal pressure vessel and main framework of the vehicle are fabricated from an interlocking series of silicon carbide films and frames of varying shapes and sizes. The toroid itself is pressurized to 25 atmospheres in order to maintain the lenticular lightcraft geometry against the propulsion system loads. The material used in the construction of the toroidal pressure vessel and hull is silicon carbide. Another key component in the framework of the lightcraft are the two high-power, parabolic rectennas that dominate nearly half the vehicle. The central parabolic rectenna is supported by ultra-light "I-beam" truses that are the only spacecraft members to take compressive loads. This basic mechanical framework provides physical integrity to the vehicle during all phases of operation. Active anti-vibrational attenuators are connected at key points in the structure. These attenuators can detect vibrational occurrences and react appropriately, causing counter vibrations, negating detrimental effects in structural members because of oscillatory fluctuations. Numerous system components are built into the hull structure, including the microwave rectennas and photovoltaic power array.SECONDARY STRUCTURE Suspended from the primary pressurized spaceframe through tension curtains is a secondary structure forming an axisymmetric envelope. The envelope is divided into 12 gores, each of which is capable of being individually sealed and pressurized. These gores are used as cabin space for the crew members and as storage space for payload or mission equipment.HULL LAYERS AND PRESSURIZATION The exterior shell of the Lightcraft is a double hull comprised of silicon carbide films 0.25 mm thick. Silicon carbide threads run between the outer and inner layers, maintaining a constant thickness of 10 mm between the two strata. This open-cell layered construction allows for the forced circulation of the helium gas coolant between the hull layers, ensuring that the external skin temperature remains within its thermo-structural limits during the brief transatmospheric boost. The external hull skin is also designed to prevent the passage of micrometeoric particles through the second layer of the hull by smashing them into small dust particles. The outer hull is compartmentalized into 48 individual cells running radially outward, with individual cells being separated by a silicon carbide curtain 0.25 mm thick. This system of separate cells ensures proper circulation over the entire hull area, facilitates repairs and maintenance, and allows for continued operation with punctures occurring in 1 or more cells. A constant pressure of 2 atmospheres of a heliox mixture fills all the main compartments during normal operations. The main torodial tube is maintained at a pressure of 25 atmospheres at all times, except during emergencies. Each of the 6 innermost compartments of the Lightcraft, along with the 12 sub-compartment crew quarters, can be sealed off and pressurized independently from the rest of the interior. The system of multiple airlocks provides added protection for the lightcraft crew at all times. around the center section of the lightcraft, maintain pressure for the hull and crew compartments.INTELLIGENT SENSOR ARRAYS RECTENNA ARRAYS The rectenna array is the main power supplier to the lightcraft. Two arrays on the lightcraft's center and rim provide the lightcraft with the power required to operate the propulsion and support systems by capturing beamed laser and microwave energy. The rectennas are able to adjust their focal length during flight to keep the desired shape under a high-acceleration load. This is accomplished by a complex system of cables and piezoelectric metals.WATER STORAGE SYSTEM A water storage system is incorporated into the structure of the lightcraft. A tube with a 22-cm diameter runs beneath the toroidal pressure vessel. This area is where the purified water that is used for the cooling system and temperature regulation systems is stored. This water is also used for drinking and food preparation.SUPERCONDUCTING MAGNETS An array of superconducting magnets provide the lightcraft with a power-storage system and support for the Maglev belt and Maglev systems. A total of 9 superconducting magnet coils run circumferentially around the lightcraft's outer and inner rims. Two primary magnets follow along the top and bottom of the toroidal pressure vessel. These are the largest magnets found on the lightcraft and provide the majority of the superconducting magnetic engergy storage unit's energy.PHOTOVOLTAIC ARRAYS The side of the lightcraft opposite of the rectenna contains the photovoltaic arrays. Twelve panels made of Galium Arsenide cover the entire surface. These panels provide the lightcraft with a source of power when the lightcraft is on the ground or is acquiring water. The Photovoltaic placement ensures that the array receives the maximum amount of incoming light while being sufficiently protected from micrometeoric particles by the hull skin.OUTER HULL MAINTENANCE To prevent dangerous electrical discharges from outer hull surface irregularities, the entire surface of the Lightcraft must be kept mirror smooth and free of foreign debris at all times during flight. To maintain the craft's structural integrity, it is also imperative that all 12 hull sections remain fully inflated. Because of these requirements, certain methods must be employed to maintain the cleanliness of the outer hull of the Lightcraft. One method involves cycling the SMES units to clean the surface. Electrical current can be pulsed through the magnets at a sub-audible frequency of approximately 20 Hz or lower. The rapidly oscillating magnetic field shakes off any dirt particles clinging to the hull. The second method that is used involves using the liquid helium coolant that normally flows through the main toroid magnets. This helium can be sprayed into the gaseous heliox coolant system, thereby rapidly cooling the outer skin. The large temperature differential between the craft's hull and the ambient atmosphere supersaturates the air closest to the ship, resulting in a cloud of water vapor that condenses at the surface and washes off, taking dirt and debris with it. MHD Propulsion System The magnetohydrodynmaic (MHD) slipstream accelerator is used for Mach numbers greater than 2. MHD acceleration involves the conversion of electric power to kinetic energy. The conversion is accomplished by the interaction of air with the on-board intense magnetic fields. The MHD accelerator is energized by beamed microwave power that is converted by the lightcraft into electric power. This conversion process is accomplished by two 35GHz rectifying antennas. The efficiency is about 85%. The antennas are configured to capture and utilize 5 to 7% of the 10 billion Watt microwave beam that is normally reflected and lost. The MHD accelerator will start when the microwave power station in space beams a direct microwave link. The propulsion system is designed to accelerate the Lightcraft in flight directions either lateral or vertical to the beam (Fig 5.0.1). Also, the lightcraft is designed for travel both around the earth and into space. The microwave beam must be aligned with the lightcraft axis of symmetry with in a few degrees of accuracy. In transatmospheric flight, the lightcraft hull reaches temperatures that exceed 2700K. These temperatures could never be accommodated without ceramic materials.  Vertical and Lateral Flight Directions The principle advantages of the MHD system are high engine efficiency in the hypersonic transatmospheric flight environment, high temperature, plasma compatibility, and savings in launch mass of expendable fuel. The MHD slipstream accelerator is used for accelerating into orbit. An electric current is discharged through the air between the rim electrodes. The action of the on-board magnetic fields and this electric discharge will accelerate the air downward using a Lorentz force. The air will create a force to accelerate the lightcraft in a direction of flight that is opposite of the Lorentz force. The Lorentz force is always directed opposite that of the flight vector. The gaseous Air Spike fore-body of the lightcraft can serve as an effective hypersonic air inlet. To exploit the atmospheric environment to the maximum the best type of hypersonic engine is an air-breathing engine.
The 35GHz microwave beam had an atmospheric transmission limit of 4kW/cm2. The transmission will target the vehicle with an 18m diameter beam centered around the vehicle's axis of symmetry. As shown in Figure 5.2.2 two rectennas receive the microwave power beam from the satellite. The two 35GHz rectennas are 18m and are located in the lightcraft interior. The rectenna panel thickness is 2.143mm, and the reflecting back plane is spaced 1/4 wavelength behind the front surface. The rectenna is a tri-polarization array designed to assure 33% redundancy of the dipole antenna elements. A high packing density of dipoles per unit area is utilized about 21/cm2 incident. The rectenna can be programmed to reflect 10% to 100% of the incident microwave power beam on demand. The rectenna is used to convert the microwave beam energy from the satellite. They convert the microwave beam into electric power. This electric power can be used by the lightcraft. The lightcraft will take the electric power to travel at subsonic speeds. An ignition circle is created around the lightcraft's periphery. The ignition circle is created by using the microwave energy to blast the air into plasma. The ionized air or plasma that is created is forced to the rim of electrodes. There are two primary super-conducting magnets located at the lightcraft rim . Both are attached to the annular pressure vessel and provide the magnetic field for the MHD accelerator. Other superconductors of a smaller ring are limited electrically with the twin rim coils to form a superconductor magnetic energy storage (SMES) unit. The superconducting magnets will catch the plasma as it expands. The plasma is caught by creating electromagnetic fields. These fields are created by the magnetic coils. Magnets create a magnetic nozzle that propels the plasma. The nozzle of the magnetic field generates a thrust. Plasma is propelled downward. This downward force will give an opposite but equal reaction propelling the lightcraft upwards. Electrodes are placed all around the lightcraft's exterior. The air that is around the lightcraft is from forced ionized air from the rectennas. The electrodes help create an electric field in this ionized air. A current will jump from one electrode to the other. This jump will help the magnets with creating a magnetic field. This energy is then refined into a direct current that is delivered to the rim electrodes of the MHD slipstream accelerators. Due to the extremely high power density of the rectenna array about 60MW/kg. The tri-polarization was selected over the dual polarization option in order to provide a 33% redundancy. The microwave beam illuminates the lower surface of the lightcraft. A barrage of energy is created from the microwave beam. This energy will break up the air. To break up the air, the energy will take the molecules of the air and separate them. When the molecules are broken up, the molecules turn into plasma. The lightcraft takes the magnetic fields to create a false surface away from the vehicle. A false surface will help the plasma be whisked away. This plasma creation and movement will shove the lightcraft skyward. The air generated by the plasma helps the shock waves to be pushed away from the surface of the vehicle. The reduction in shock waves creates a smoother ride for the passengers of the Lightcraft. One fundamental component of the Lightcraft's propulsion system is called an Air Spike. Originally proven at Mach 10 in late April 1995 at Rensselaer Polytechnic Institute, the Air Spike concept is used only at supersonic flight velocities. The air spike system (see fig. 5.5.1) uses the parabolic microwave reflector, located on the top hull of the lightcraft, to reflect part of the microwave beam to a point ahead of the vehicle. An explosion occurs here and shock waves are created ahead of the lightcraft. The shock waves drive air out of the vehicle's path, and thereby greatly reducing drag and creating an inlet for the Lightcraft's MHD Fanjet. The Lightcraft employs an active Thermal Management System (TMS) to reduce the excess heat generated in flight during various propulsion modes. This preserves the structural integrity of the ship's hull as well as maintaining acceptable temperature levels for human survivability. The TMS uses the breathable heliox mixture which inflates the craft to draw excess heat away from the rectennas, and converts it to steam to be jettisoned from the craft during heat critical maneuvers.
The axial flight mode is certainly the most common when using the MHD engine. Axial flight is used exclusively for high G acceleration into space. In a region of dense atmosphere, however it may be desirable to use the MHD engine in lateral flight direction. The lateral flight direction will be used until the lightcraft climbs out of the dense atmosphere. Then switched to the axial flight mode. A hyper-jump, although usually done in a vertical (i.e. axial) direction, is sometimes made in an oblique or horizontal (i.e. lateral) direction. If the MHD engine is used for such a hyper-jump, the lateral flight mode is a necessity. A key to being able to use the MHD accelerator in the lateral mode is the ability to create a wedge shaped Air Spike over the leading edge. The Air Spike is pulsed to reduce compressibility effects on drag along the effected length of the vehicle. The objective is to change the high drag around the shock patterns that form over the leading edges of the lightcraft into low drag oblique shock geometry. Due to the oblique shock wave, asymmetry over the lens shaped vehicle effects the vehicle when it is accelerating rapidly. The pulsing of the Air Spike greatly reduces vehicle drag and heat transfer. This makes axial flight mode more efficient and capable of higher acceleration performance. Another concern in the lateral flight mode is the positioning of the power station. Specifically, if the axis of symmetry is not aimed directly at the station, as it is in the axial flight mode, the MHD engines can not function. The MHD engine will not be getting enough of the microwave beam. When traveling laterally, there are therefore two options. The first option is to travel a circular arc path. Hence, the satellite power source travels along the segment of the microwave beam. This makes the lightcraft fly along the radius of the circle that is created. At any point on the circular path, the lightcraft departs the arc and coast engine off until it pitches over to enter the next arc segment. The second option is to receive the microwave energy when the lightcraft is aligned with the energy source. This momentum accelerates the lightcraft using the MHD in lateral flight. The lightcraft can then coast at this new velocity. Then, the pulsed detonation engine (PDE) when running on internal SMES power does not require the beam. The CCFS can be used to change from the MHD lateral flight mode to the PDE mode. The PDE mode can be used to vector the lightcraft at any point into alignment for the next power pulse. At the next power pulse the internal power of the MHD accelerator is fixed again. This second option for lateral flight mode offers more flexibility than the first. The problem is that it is greatly restricted at lower flight speeds. Pulsed Detonation Engine (PDE)
The PDE is the most versatile propulsion system of the three employed on the lightcraft. It is capable of producing flight speeds from 0 to Mach 2.0 without the lateral air spike (and up to Mach 6 while employing the air spike) and can function effectively from sea level up to about 20 Km in altitude. One of the most important functions it serves is as the initial propulsive unit responsible for rapidly accelerating (up to 300 Gs) the lightcraft to Mach 2.0. From here the MHD fanjet engine can function effectively and complete the boost to orbit. The PDE's ability to perform from a standstill allows for effective evasive maneuvers such as "blink outs" in hostile environments when the crew might not be situated for a full boost to orbit. A "blink out" is simply a rapid acceleration (greater than 20 Gs) that is unable to be followed by the human eye. The result is simply conveyed as the illusion of the craft disappearing.
The Lightcraft is powered by microwave radiation beamed from an orbital power station with super accurate pointing and tracking capabilities. With the cooperative lightcraft "target". The spin axis of the lightcraft must be aligned to within 1 or 2 degrees of the incident microwave beam whenever line of sight allows successful beam transmission. The lightcraft's reflective rectennas can support the use of several wavelengths of microwave power depending on the weather, the propulsion mode being operated in, and the craft's location in the atmosphere. Viable wavelengths range from 0.3 mm to 10 mm. Shorter wavelengths have a higher breakdown intensity and this intensity decreases for all wavelengths as the craft gains altitude. Ion Propulsion System The Lightcraft ion propulsion system is used primarily for subsonic, low-performance maneuvers. These maneuvers generally include aerial taxiing, passenger retrieval functions, and low-observable covert operations. The maximum speed the Lightcraft can attain using this air breathing propulsion system is approximately 160 km/h. The key to the success of the Lightcraft's ion drive system is the buoyancy of the Lightcraft. The heliox gas mixture that pressurizes the craft also provides approximately 16.5 kN of lift at 20 degrees Celsius. At that temperature, the ion propulsion unit needs only to provide an additional 8 kN of lift to hold the 24 kN vehicle in the air. The pulsed ion propulsion system that is integrated into the Lightcraft differs from its predecessors in its lack of physical cathodes and accelerator grids. The craft emits pulsed 1 MeV electron beams, thereby becoming positively charged as it forms a negative ion cloud in the direction of travel. The electrons attach themselves to oxygen and water vapor molecules in the air, thereby forming negative ions. These ions are then attracted toward the ship through a large electric potential, and this momentum exchange with the atmosphere results in a distributed electrostatic thrust force on the Lightcraft hull. In most cases the ion propulsion system must produce a vertical component of thrust because the vehicle is only partially buoyant. This vertical component is a result of charged air rushing over the top of the craft as it is accelerated downward through an electric potential. The wake left by this rushing air creates an "ion plasma cone," within which air is recirculated. In flight, this cone looks like a tail hanging off the bottom of the Lightcraft The loading that the ion propulsion system induces on the disc is an important characteristic, just as it is in conventional rotorcraft. This disc loading is well within an acceptable range, however, as can be seen in the graph below ; it is an entire order of magnitude lower than the rotor loading of even standard ultralight helicopters.
In free air, the charge cloud has a decay time of about 4 ms, which means in order for the cloud to produce sufficient thrust, it must be recharged frequently. In fact, the electron accelerators pulse between 10 Hz and 200 Hz in free air. Once the ion cloud is formed, it expands and is attracted toward the ship simultaneously, dragging much of the surrounding neutral air mass along with it. This process produces a low-pressure region in front of the craft, which translates into increased forward thrust. The force of this thrust can be calculated, and is given for three different cloud configurations in Table 7.2.1. The corresponding maximum lateral velocities are also given. For representations of these three ion cloud configurations.
The GaAs array is approximately 25% efficient in the solar-powered mode, but as high as 60% efficient in the laser-powered mode. Of course, power densities in the laser mode are significantly higher than in the solar mode; active heliox cooling of the hull becomes extremely important under laser power. Table 7.4.1 gives power densities and maximum power outputs of the GaAs array under both solar and laser power in nominal conditions. Maximum thrusts are based on available energy and a thrust/power coupling coefficient of 30 kN/MW. Actual thrusts are also dependent on atmospheric conditions, equipment specifications, and other variables.
The outer hull surface of the Lightcraft is covered with electric and magnetic field sensors, which feed this critical data back to the Central Onboard Processor, to precisely control the electric potentials everywhere around the craft. This monitoring helps in the prevention of electric discharges and in the immediate repair of discharged areas of the ion cloud. When the potential between the ion cloud and the Lightcraft exceeds the breakdown threshold of the local atmosphere, an arc discharge, similar to atmospheric lightning, occurs. This discharge destabilizes ion cloud formation momentarily in regions near the arc, because the negative charge is attracted back to the positively charged hull. The computer senses this potential drop and compensates as much as possible. In the event of multiple discharges and subsequent attempts to repair the ion cloud, however, flight will become erratic. Rolling the Lightcraft requires charge ejection from both lateral sides of the Lightcraft at right angles to the flight direction. A rolling maneuver is carried out if we assume magnitude of the charge, and ejection angle of +- 30 degrees used in the pitch maneuver, resulting in a pitch rate of .576 rad/s. To induce a 90 or a full 180 degree flip, the +- 30 degree clouds must be ejected, or for quicker rates the +- 60 degree clouds should be ejected.
The Lightcraft routinely executes a number of low-performance maneuvers that use the ion propulsion system to evade detection by potential threats. These maneuvers include a low-noise, low-visibility silent running mode, microwave beam engagement procedure, and two methods for hiding among and within cloud cover. Power Beaming Microwave Power Beaming A microwave beam can be used to power the Lightcraft externally during high-power operations such as PDE and MHD flight modes. The microwave beam is transmitted from a power station in space. A satellite in orbit takes sunlight and converts the light into microwave power. The microwave power is then converted to a beam much like a light beam. This beam is then pointed at the center of the lightcraft and will target the vehicle with a 18m diameter centered around the vehicle’s axis of symmetry. A computer controlled feedback system (CCFS) on the Lightcraft sends the craft’s coordinates to the satellite. The satellite then directs a beam in the direction of the coordinates of the lightcraft. A few degrees of accuracy is all that is needed for the lightcraft power beaming system. The CCFS can achieve this degree of accuracy without any problem. There are several satellites in orbit so even if one satellite is located on the other side of the earth, a beam can still be created. The satellites also store the microwave beam energy that they do not use. This is beneficial in case a satellite on the dark side of the earth needs to be used. Microwave Power Receiving The rectenna is used to convert the microwave beam energy from the satellite into electrical energy used by the Lightcraft’s systems. The Lightcraft uses the electric power in every flight mode, be it at subsonic or supersonic speeds. Two rectennas receive the microwave power beam from the satellite. The two 35GHz rectennas are 18m in diameter and are located in the lightcraft interior. The rectenna panel thickness is 2.143mm, and the reflecting back plane is spaced ¹ wavelength behind the front surface. The rectenna is a tri-polarization array designed to assure 33% redundancy of the dipole antenna elements. A high packing density of dipoles per unit area is utilized of about 21/cm2 incident. The operating efficiency of the rectenna array when in use is about 85%. The rectenna can also be programmed to reflect 10% to 100% of the incident microwave power beam back into space on demand. Other uses of the rectenna array include emergency Air-Spike support, protecting the magnets, avoiding collisions with the PDE engines, communications, and as an array radar.  The Maglev Lander is a vital part of the Lightcraft. It is designed for 3 main functions as well as several less vital ones while in atmospheric flight. Three main subsystems are responsible for the successful operation of the Maglev Belt System (MBTS). All are vital.
 In order to use the maglev belt a passenger would stand in a large open area, preferably more than 10 meters across. This area must not contain any iron due to the strong magntic fields. The lightcraft, hovers above and gradually pulls the passenger up using the MBTS. The maximum distance that the lightcraft could lift a person is approxiamtely 15 meters, depending on the persons weight. Normally, the passenger would enter into the lightcraft through doors used by the maglev lander. However, in emergency situations, entrance into the lightcraft can also be made via an open ramp door or through the escape pod tubes. These two entrance methods involve more risk and are therefore used only in emergencies. The lightcraft is also designed to enable extravehicular activity (EVA) in space for the emergency repair of the hull and other systems. It must, however, be stressed that the EVA is normally reserved for emergency purposes only. When preparing for an EVA a worker would put on a special EVA suit, equipped with micrmeteorite armor, maglev belt, and the proper tools. The space suit is physically and magnetically tethered to the lightcraft to prevent the worker from drifting off. The worker generally exits through the maglev lander and only after shields have been turned off. While in space, the worker's position is mainly controlled magnetically through the interaction of the maglev belt with the lightcraft's magnetic fields. The worker's suit also contains a mini-reaction control system, similar to NASA's "Manned Maneuvering Unit" (MMN). If however, both positioning system experience failure, to prevent the worker from floating off into space the lightcraft contains a back-up system. The maglev landers can be magnetically deployed from the lightcraft and sent out a short distance to rescue the nearly lost crew member. Emergency Operations Safety is the single most important factor in the design of the Lightcraft. It is designed to maintain, and, in fact, maximize the safety of its crew at all times. The key safety feature and controlling mechanism for ensuring the safety of the vehicle is the Lightcraft's Smart computer. This advanced central computer monitors and operates all of the vehicle's safety features. ENVIRONMENTAL CONTROL SYSTEM The environmental control system is the most critical of the Lightcraft's major systems. The multiple redundancy of this system maximizes the crew's safety and protects them from the unlikely event of multiple life support and propulsion system failures. The Lightcraft is inflated with heliox at 2 atm. pressure, and this gas is used for life support of the crew, and cooling of various Lightcraft systems. The heliox plenum system receives the cooled heliox from the cooling system and recirculates the cooled heliox for use throughout the Lightcraft. Before the cooled heliox can be used for human respiration, the heliox must pass through the heliox life support system. The heliox life support system revitalizes the heliox, removes excess carbon dioxide and other potential toxins, and filters out particles to the waste management system. The following section describes the heliox life support system in detail. A contamination sensor monitors the quality of heliox and controls the flow of heliox around the Lightcraft. When the contamination sensor detects the failure of the heliox life support system, the sensor automatically shuts down the defective system and alerts the crew. There are three parallel heliox life support systems in the environmental control system, which operates at 33% of its full capacity in normal operational condition. This gives 300% redundancy to protect the crew from even the unlikely event of multiple life support and propulsion system failure. Approximately, one pair of atmospheric sensors for every 1 m3 of the interior volume is located throughout the Lightcraft. The sensors work at the rate of 0.1 seconds per sensor and control the temperature and humidity of heliox throughout the observation deck, console, etc. These sensors are also used for fire detection inside of the Lightcraft.ATMOSPHERIC HELIOX SYSTEM On board the Lightcraft are a number of life support systems that are essential for crew survival. An example is the Atmospheric Heliox System, which is used for crew respiration. This system controls the levels of heliox, water vapor and carbon dioxide in the atmosphere. It also filters out molecular and particulate contaminants, while condensing the OPFC, Oxygenated Perflourocarbons, for recycling. The helium-oxygen mixture is normally breathed in the main cabin and maglev landers of the Lightcraft in a pressure of 2 atmospheres. During low subsonic operations the atmosphere may reach a minimum of 1.1 atmospheres, but anything lower than that would cause the ship to lose its structural integrity. The 2 atmosphere He/O2 mixture in the Lightcraft has a partial pressure of 69 mm of oxygen; It is commonly used by deep-sea divers. Artificial intelligence computers linked throughout the Lightcraft regulate the heliox respiratory system. These computers recirculate the air and filter out the impurities, restoring the heliox composition to within normal parameters.ARTIFICIAL GRAVITY GENERATION
The emergency environmental support systems were created for the unlikely event of a failure of the main support system. They were designed to protect the crew and prevent the complete loss of a system or the craft itself. Several emergency alert levels can arise and each level requires a specific, timely response. The outer corridor of the Lightcraft is divided into sections by pressurized bulkheads. The rooms in these bulkheads are airtight when the doors are sealed. As in a naval submarine, if a breach of the hull occurs, the bulkhead doors automatically close shutting off those sections from the rest of the ship. This protects the integrity of the Lightcraft's inflatable structure. The engineers on board and the artificially intelligent systems built into the ship need to evaluate the emerging situation and try to rectify it before a disaster occurs. However, if the situation cannot be corrected or more serious problems occur, the crew will evacuate into the inner chambers of the Lightcraft and enter their escape pods. The pilot, co-pilot and engineers are the last to leave the ship, and will attempt to repair the damage. Emergency extra-vehicular activity (EVA) equipment such as helmets and gloves are also located in throughout the ship in case the atmosphere in the ship is not one in which the crew can safely work. If the complete failure of the Lightcraft structure is imminent the crew is to begin partial liquid respiration and the escape pods are ejected to remove them from harm as quickly and safely as possible. The release of the escape pods is a last resort, however.WASTE MANAGEMENT The Lightcraft sustains a closed ecological system to support its crewmembers. The main purpose of the waste management system is to make optimal reuse of waste products in order to minimize the storage space of expendables and the initial launch mass of the vehicle. The liquid waste and the solid waste are directed to their separate respective containment tanks. A special hazardous waste containment tank is designed to store any toxic, radioactive, or biohazard substances. These hazardous wastes are unloaded after the vehicle lands (or docks with a space station). The liquid waste recycling unit uses a series of mechanical and electrical filtration processes to separate solid and liquid waste. Also, OPFC is recycled in the liquid waste-recycling unit. In the solid waste-recycling unit, the solid waste is compressed and the liquid is extracted and the resulting liquid-waste is transported to the liquid-waste recycling unit. High-density solid waste containment unit stores the remaining (or residual) solid waste until it can be discarded. After finishing the recycling process from the liquid waste recycling unit, the recycled liquid goes through a microbial treatment and the quality of the recycled liquid is monitored. Any liquid that is unable to be reused or re-purified is dumped in a retrograde direction, (a direction opposite to the way the Lightcraft is traveling). The recycled liquid is now ready to be used by crews. CREW SUPPORT The one key element essential to the success of every Lightcraft mission is the crew. These 12 men and women have been chosen for their knowledge and abilities to support specialized Lightcraft missions. The crew is number 1 on the priority list at all times. The nature of these missions can create stress for the 12 officers on board the Lightcraft. The crew must give 100% in all situations, even in times of disaster or extreme danger. For this reason, human factors and ergonomics have top priority. The crew must live comfortably and work within this small volume at top efficiency without interfering with one another. The crew positions require individuals with special training. The personnel on board the craft include pilots, communications officers, engineers, and mission specialists. Along with these officers who are focused on the mission and Lightcraft maintenance are individuals who are focused on the crew. One of these people is the medical officer. This officer is a skilled surgeon as well as a general practitioner. A counselor is also available for the crew. This individual is a trained psychiatrist/psychologist who knows the details of the mission and has the foresight to anticipate the problems that may trouble the crew. The missions can be highly stressful, crewmembers will need a release. This release is provided by having someone to talk to. Along with specialized crewmembers, lounges are provided for the crew to relax and socialize in. They can eat and spend time together, or find a quiet spot to be alone, perhaps for virtual reality diversions.MEDICAL SYSTEMS The medical area is two small rooms near the center of the ship. The inner room is the operating or examination room while the outer room is the doctor's office. The examination room contains a few special beds that can be used either as examining tables or sleeping quarters for injured personnel. The on-board computer assists the doctor and a mechanical arm is used as an assistant in emergency surgeries. This arm is connected to the computer and is equipped with sensors so that it knows what to do without explanations from the medical officer. The ship is also equipped with body-scan equipment that examines the wounded area and reads out its results onto a computer console. This magnetic resonance imaging (MRI) equipment takes advantage of the Lightcraft's 1-2 Tesla field produced by its superconducting magnets. The medical facility also contains a variety of different drugs and vaccinations that may be required throughout the mission. Special equipment such as molding splints is also used. These braces use sensors and the lab computer to conform to a broken limb and set it as a cast would. The medical facility is designed to handle several simultaneous, time and resources are limited on these missions. If the crewmember needs major surgery or reconstruction work, but is stabilized and is not in danger of getting worse, that person is placed on life support systems within an escape pod. The computer continually monitors the individual and keeps the doctor informed of the situation. The person is then transported to a hospital at the earliest possible moment.CREW QUARTERS SYSTEM The Lightcraft is equipped with individual quarters for all 12 crewmembers. Each room is set up so as to accommodate the crew's sleeping needs, regardless of the endo-atmospheric or space environment during the mission. Each room is equipped with a lightweight, inflatable futon or bed, which folds out from the wall. When not in use, it is stored in a vertical position, latched to the wall. The bed can be deployed 2 different orientations, depending on whether it is being used on Earth or in zero-gravity space flight. During space flight, the bed functions in a vertical or upright position, and is equipped with a cushioned sleeping satchel. The person simply climbs inside the satchel and zips the bag closed. The crewmember is then strapped back against the wall to prevent movement during flight in the 1/5th Gravitational gravity environment. When traveling on Earth, the bed can be folded down from the wall into a horizontal position.FOOD REHYDRATION UNIT As with all life forms, humans must remain in top physical shape to perform at their best. In order to do this they must receive three square meals a day. Life is no different aboard the Lightcraft. On board they can select from a variety of dehydrated foods. These foods are packaged to minimize their launch mass. The rehydration of food is accomplished using the purified and deionized water that is stored on the ship. The food is available in the main cabin area. The diner chooses a meal from storage bins on the wall and inserts the package into a rehydration terminal. After the crewmember enters the food category into the console, the computer automatically injects the appropriate amount of water at the right temperature and bakes or cools it as necessary. All the food is fortified with the vitamins and minerals needed to keep the crew healthy. Requests are solicited from the crew before mission begins to determine what types of food should be brought aboard. Space is limited, but great pains are taken to accommodate some of the crew's favorites. Snacks are also available to the crew, but like any other mission, the selections are limited to those that will provide nutritious and balanced meals.HIGH-QUALITY VR ENVIRONMENT LIFE SUPPORT OPTIONS Of all the major systems on board the Lightcraft, the life support systems are among the most important. The loss of these systems could result in the loss of the entire crew, and with them, the mission. For this reason, several options for life support systems are available. In the main cabin of the Lightcraft and in the mag-lev landers, the crew breathe an oxygen-helium mixture known as heliox. This mixture replaces the normal nitrogen component (i.e. the normal dilutent) in air with helium. Within the escape pods the crewmembers are given a choice of breathing apparatus. If very high accelerations are not required the high-pressure heliox breathing system can be used. Otherwise partial liquid ventilation is mandatory for the protection of individuals. Partial liquid ventilation fills only the deepest sections of the lungs with liquid. The rest is filled with heliox. Breathing heliox in this manner requires the assistance of a respiratory unit. This unit senses when the body wants to inhale and exhale and provides help. The crewmembers have two choices of ventilation systems. The most commonly selected method requires 2 tubes to be inserted into the nasal cavity, down the back of the throat, between the vocal chords, and into the lungs. The second option involves the surgical implant of removable connections for the liquid breathing tubes. The tubes may be placed into the trachea, just below the vocal chords, and then slid into the lungs. This option keeps the face free of tubes and offers the most mobility of the head. The advantage of retaining the ability of verbal communication can also be found with this option. With the first option VR goggles are the only mode of communication.ULTRA-G PERSONAL PROTECTION SYSTEM The revolutionary ultra-G space suit is the body protection required for all personnel aboard the Lightcraft. This suit is to be used when traveling at high speeds as well as for any short-term space activity. It has a skin-tight flexible scuba diver's pullover headgear that is microwave reflective. The gear also contains virtual reality goggles with direct retinal projection by LEDs for both communication and relaxation purposes for extended missions. The goggles are designed to "fog" when hit by a laser beam to protect the eyes from damage. The suit is also equipped with microwave reflecting form-fitting integral boots. A microwave-reflecting grid is provided for the mouth, nasal, and ear cavities. Optional equipment includes a collar designed to accommodate a fish-bowl helmet. An optional maglev belt with a flexible battery pack is also available for special missions. The suit itself is made of a skin-tight, spandex-type microwave-reflecting material. The standard-issue suit has a liquid-filled liner that inflates against the armor of the MIRV escape pod so as to leave no voids. This procedure, along with liquid ventilation, enables the occupant to withstand high accelerations. All personnel assigned to the Lightcraft will be equipped with a custom-fit suit. It is to be worn at all times unless authorized to do otherwise.LIGHTCRAFT BOARDING OPTIONS
The interior of a MIRV escape pod is custom-fit to each individual. The pod is lined with a form-fitted rigid and lightweight shell with a liquid inflated cushion that outlines a specific body. This liquid cushioning layer is roughly 1-cm thick and assists in minimizing damages to the human body during ultra high-G maneuvers. The lining shapes itself around each body therefore making the escape pods universal in their use. The lining provides a cushioning as well as support for the human body. Also the 1-cm of liquid provides adequate protection against the soft radiation released when the Lightcraft disables its space "plasma shield." If the need arises, personnel are able to remain within the escape pods for periods of up to 1 hour. The virtual-reality system in combination with the inner lining provides for comfortable extended missions. The pod has a temperature control to accommodate the desires of the human being inside of it. The virtual-reality system allows each person to adjust complete environment of his/her own pod. A latch is provided on the inside for manual opening of the pod's hatch. It can also be opened through voice control. The Lightcraft's escape pod is designed to accommodate individuals ranging from 5- foot 1-inch to 5-foot 4-inch only FLIGHT OPERATIONS Flight operations of the Lightcraft Lightcraft can be sorted into either performance-related or mission-related categories. The performance-related operations consist of the flight modes required for the successful functioning of the lightcraft itself. These operations include all flight systems necessary for the lightcraft to take off, accelerate, maneuver, land, etc. The lightcraft has 5 basic quasi-continuous flight cruise modes that it can employ: (a) covert hover, (b) low observable, (c) reduced power, (d) pulse detonation engine (PDE) flight, and (e) Magneto-hydrodynamic (MHD) flight. Reconnaissance missions conducted beneath the cumulus clouds of the atmosphere require the "covert hover" mode. When a mission requires that the vessel be difficult to detect or recognize, the "reduced power" mode is used for silent running. An ion-propulsion hover is maintained in the "low observable" mode (LOM). While in the "PDE flight" mode, the lightcraft may either hover or rapidly accelerate according to the dictates of the mission. In addition to the previously described 5 basic cruise flight modes, the Lightcraft Lightcraft can perform 5 basic types of maneuvers: (a) In order to avoid detection, the lightcraft is equipped for the hyperjump function. (b) Being hyper-energetic, the Lightcraft is capable of high-G acceleration directly into space. (c) The lightcraft is also capable of subsonic thermaling flight with large squadron of lightcraft. (d) During take-off and landing the lightcraft operator has a wide selection of appropriate aeronautical maneuvers at his disposal. And (e) the conventional pitch, roll, and yaw...MISSION TYPES The Lightcraft has been designed for hyper-energetic space command missions. The extreme speed, ultra lightweight design, and maneuverability of the lightcraft make it suitable for a wide range of operations. Typical missions for the Lightcraft fall into one of the following categories: Retrieval of downed lightcraft. The Lightcraft has the capability of lifting its own mass (2400 kg) with its maglev coils. This ability enables the lightcraft to pick up another intact but non-operational lightcraft and transport it to a safe location for repair of sustained damage. In a situation where the lightcraft is damaged beyond repair, it may have to be destroyed. Most lightcraft are designed to self-destruct if necessary, principally by rupturing the SMES unit coils when fully charged. The black boxes are designed to remain intact after lightcraft accidents. The Lightcraft is equipped to efficiently locate and retrieve critical black boxes from the debris in a rapid response, alert scenario. The Lightcraft and crew are capable of sustaining accelerations up to 300 Gs. In the event of an emergency, the lightcraft can bring supplies to anywhere on Earth in less than 45 minutes. This feature enables the lightcraft to travel to the moon in about 5.5 hours. The lifting strength of the lightcraft PDE-flight combined with maglev coils affords the vessel the ability to abduct a number of different ferromagnetic objects of varying weights, shapes, and sizes.FLIGHT MODES AND MANEUVERS CRUISE MODES Under normal condition, the Lightcraft Lightcraft is capable of sustaining cruise at various flight speeds, ranging from subsonic to hypersonic. Depending on the mission profile, the crew can choose from the 3 propulsive devices on-board to achieve the desired velocity and features. SUBSONIC CRUISE When operating for long periods inside of the atmosphere, the lightcraft generally has a subsonic cruising speed. In this mode, the craft uses its ion- propulsion system to achieve a maximum speed of approximately 150 km/hr. The principle of forward flight for the lightcraft is quite similar to that of the late 20th century helicopter. SUPERSONIC CRUISE HYPERSONIC CRUISEWith the help of pulsed-detonation engine (PDE) and the Air Spike, the Lightcraft can easily accelerate beyond the speed of sound. The vehicle can achieve supersonic speed either laterally with a linear Air Spike just in front of the leading edge, or with the centerline parallel to the air stream. However, the crew must ensure that the incident microwave beam is exactly aligned with the vehicle axis, or the craft will not receive a sufficient amount of power. The hypersonic MHD thruster is mostly used to attain a velocity sufficient for leaving the Earth's atmosphere. In addition to providing the necessary thrust for escaping Earth's gravity, the MHD engine is also capable of accelerating the Lightcraft into hypersonic dashes inside of the atmosphere, with the help of the Air Spike. In this mode, the Air Spike is activated to reduce the drag and the MHD slipstream accelerator is used to push the craft into the hypersonic regime. Both lateral and vertical flight modes are accommodated by the engine, which can alleviate the bow shock wave, or "sonic boom".BASIC FLIGHT MANEUVERS The Lightcraft Lightcraft is designed to fulfill a broad range of Space Command missions, including reconnaissance, surveillance, and rescue. With its unusually versatile thrust vectoring ability, the craft is capable of various exotic and hyper-energetic maneuvers. *Pitch and roll. With its ion propulsion engine, the Lightcraft exhibits low pitch and roll rates typical of conventional fixed-wing aircraft. In contrast, the PDE thrusters give a lightning-like responsiveness in pitch and roll. *Flip maneuver. Useful upon takeoff to receive the high power microwave beams from the orbiting energy station. The ion propulsion engine can perform this 180-deg. rotation in approximately 3 seconds. *Pendulum/ oscillatory maneuver. Mainly used to align the rectenna with the microwave beam during maneuvers, so as to receive intermittent power for propulsion. *Station-keeping. Used during surveillance and reconnaissance missions, at high altitude, to provide the on-board sensors with a stable platform. The vehicles perform this circular flight mode while tracking the microwave beam and derive the performance benefits of aerodynamic lift in maintaining this "holding pattern." *Spin. Using elements of both PDE and MHD propulsion system, the Lightcraft Lightcraft can initiate and maintain a desired rate of spin (i.e., yaw rate) to provide a gyroscopic stability effect.HYPERJUMP TO EVADE DETECTION Should the need arise, the Lightcraft can convey the illusion of instantly disappearing from sight. This hypersonic "jump" maneuver, called the "hyperjump," is normally accomplished while linked to off-board power, but for distances less than 11 km, stored magnet energy can also be used. The hyperjump can be oriented in any direction, but is most often performed vertically. The primary requirement of the jump is that it be faster than the eye can follow, which is beyond an acceleration of 20 Gs. As always, the lightcraft begins its motion with the PDE, which can be vectored until the vehicle is in position to use the MHD accelerator. An average jump distance is 2-10 km vertically, which is sufficient to reach the cover of clouds 90% of the time. The pilot can choose an acceleration rate for the hyperjump. At 20 Gs, a 2 km jump will require 6.4 seconds; at 100 Gs, the same jump takes 2.9 seconds; at 200 Gs, it would take 2.0 seconds; at 300 Gs, it would take 1.6 seconds. The decision on what acceleration rate to use is simply a matter of which the pilot deems more important, energy or time. Occasionally on extended ventures in unfriendly airspace, a high-power microwave beam may not be available when needed, and thus the MHD accelerator is unusable. A 2 km lateral hyperjump can still be made using the PDE exclusively, although the blunt vehicle cannot be pushed much past Mach 2 (approximately 680 m/s). The acceleration rate cannot be greater than 23.5 Gs, which is a jump lasting 5.9 seconds. In order to make the jump undetectable, no expendable water coolant can be ejected that would leave a visible vapor trail. Fortunately, the hyperjump is very short in duration. Hence, a small quantity of liquid helium is instead injected as a coolant into the vehicle's pressurized hull and not expelled from the vehicle after "consuming" the waste engine heat. As the Lightcraft undergoes massive accelerations (e.g., beyond 30 Gs) during hyperjump, it is necessary for the crew to be secured in their escape pods and to be breathing pressurized heliox. It is impractical for all the crew to be constantly climbing into and out of their escape pods, so the crew would normally remain in their pods if it is expected that a hyperjump may be neccessaryHIGH-G ACCELERATION INTO SPACE Making the high-G leap into space is one of the primary design criteria for the Lightcraft lightcraft. This function is performed by using the PDE to punch through mach 1, then switch to MHD mode and accelerate toward the orbiting power station, located directly above the lightcraft, in orbit. Orbital mechanics ensure that the lightcraft never collides with the power-beaming station in orbit, and a flight plan is easily created to navigate the lightcraft around the Earth, to the desired destination. The lightcraft's ion propulsion engine can receive a low-power microwave beam from any incident angle upon the rectenna. However, both the PDE and MHD thrusters require that the microwave beam be exactly aligned to the rectenna axis of symmetry in order to operate in the high-power mode. The PDE is used to accelerate the lightcraft, lateral to the beam, up to Mach 2, keeping the microwave beam aligned with the rectenna. The PDE thrust is then vectored to rapidly pitch the lightcraft until its central axis is aligned with a new microwave beam, whereupon it accelerates directly toward this next power station. At this point, the switch is made to MHD slipstream accelerator mode and the lightcraft continues into space. The occupants must be breathing pressurized heliox mixture in their escape pods during this operation. It is necessary to take on 2400 kg of water coolant before initiating high-G acceleration to orbital velocities. This water is expended as steam during the run.HOVER OR RAPID ACCELERATION IN PDE MODE At sea level altitude, the ion propulsion system produces only enough lift to support half the vehicle mass of 2400 kg; the rest of the force needed for flight comes from the natural buoyancy of its pressurized helium gas. When flying at altitudes above 5 km, the buoyant force helping lift the Lightcraft is greatly reduced, requiring substantially more thrust from the engines than at sea level. The ion-propulsion engine is not capable of supporting the vehicle at high altitudes; thus, the PDE thrusters must be employed in this regime. For the case of hover, the PDE exhaust gases are vectored straight down. Like the MHD engine, PDE thrust can be vectored in most any direction, allowing highly agile control and lightning-like maneuvering abilities. For this reason, the PDE is most effective in demanding situations such as combat. From a motionless hover the PDE thrusters can accelerate the craft up through Mach 2 in a heartbeat, easily demonstrating 200 Gs-- giving the Lightcraft a distinct advantage in evasive maneuvering prowess over most any opponent. It is not necessary for the crew to be in the escape pods during low-acceleration (less than 3 Gs) flight in the PDE mode. Lightcraft control can be easily maintained through the personal access displays. However, in tactical situations, it is highly encouraged for the crew to remain in their escape pods because more options are available when rapid acceleration is possible; in friendly territory, when there is very little need for such energetic maneuvers, the escape pods are unoccupied.PICK UP WATER-FILLED MAGLEV LANDER IN PDE MODE
The Lightcraft can land using one of the following "gear" options: a) the auxiliary tripod landing gear, b) 3 or more extended escape pods, or c) a Maglev lander deployed as a "foot."AUXILIARY TRIPOD LANDING GEAR The Lightcraft is equipped with auxiliary tripod landing gear to be used when the lightcraft is partially buoyant and carrying no water ballast. This landing gear can also be used to anchor or "tie-down" the lightcraft close to the ground in windy conditions. Each landing gear leg is a lightweight telescoping assembly that extends from the lightcraft to keep the vehicle up to 5 meters off the ground. Each leg has a foldout inflatable footpad that ensures that the landing gear does not sink into soft ground. The landing gear is deployed through portholes in the photovoltaic array with the gear extension actuators supported by three of the inner compartment walls. A double action pneumatic piston assembly extends the landing gear. Once the main assembly has cleared the vehicle, an internal set of pneumatics extends the landing gear until the desired length is reached and the footpads are deployed. Two different footpad diameters are currently in use on the Lightcraft: a 1.2-meter, and a 1.5-meter. The small bladder assembly is to be used when the expected gear load is 1200 kg. The large bladder assembly is to be used when the expected gear load is 2400 kg. (vehicle is depressurized, zero buoyancy). These large foot prints allow the Lightcraft to be set down upon very soft ground without settling, and the semi-spherical shape does not permit water or mud to collect on top of the gear. Each bladder is retracted into a protective cowling before the leg gear is retracted into the lightcraft after takeoff. The pneumatic deployment systems of the telescoping landing gear can be activated in such a manner so as to spring the vehicle into the air. At first the gear is shortened to bring the vehicle close to the ground; then it is extended quickly to propel the vehicle upward. Once extended fully the landing gear would be immediately retracted into the vehicle, so that the hull exterior can be charged for the ion propulsion flight mode.RESCUE PROCEDURE FOR DOWNED LIGHTCRAFT BY ANOTHER When a lightcraft is in danger of collision or other massive damage, its Smart Computer activates all applicable safety maneuvers and operations to preserve the vehicle and its crew. In the unlikely event that the computer's evaluations determine that the ship cannot be saved, it ejects the crew in their escape pods and allows the ship to crash. The computer determines the least destructive crash configuration for the failing lightcraft, and works to minimize the impact damage and maximize its survivability potential. If the computer has remained operational after collision or other vessel trauma, it will aid rescue and recovery operations of the ship. The survival of the Computer and subsequent recovery of any downed or injured ship is a major priority. Consequently, the ship and its components have been optimally designed to facilitate retrieval and recovery. The lightcraft's loss could prove very dangerous because of highly advanced technology it represents-- in particular its extreme speed and agility. To preserve security and our technological lead, a lightcraft would immediately be deployed to retrieve a downed one. The retrieval process can be done as a flyby. The rescue lightcraft first positions itself over the downed craft where the lander has landed to contact the upper hull. Next the Maglev coils in the downed craft's upper hull would be activated. Acting together, these coils have sufficient attraction force to allow the response lightcraft to lift the empty craft and carry it to safety using its PDE engines. If recovery of the downed lightcraft is impossible, (e.g., its magnetic coils are inoperative), an attempt must be made to recover its black boxes and flight Computer, and the vehicle would be destroyed beyond recognition.WATER COLLECTION FROM CUMULUS CLOUDS One useful feature of the Lightcraft is its capability of filling its water storage tank using the water vapor in cumulus clouds. Clouds are comprised of water droplets, their size on the order of micrometers. In a continental region, there are generally around 500-1000 water droplets per cubic centimeter. This corresponds to a density of approximately 0.5 g/m3. In order to attain 2400 kg of water, it is therefore necessary to sweep out the volume of a cube of 150-350 meters per side. Most clouds are 10-50 times this volume. The Lightcraft cloud mining procedure is performed while using the PDE thrusters, and begins with actively conditioning the hull temperature to aid the condensation process. The droplets turn to ice in temperatures around -5 degrees Celsius, and in such instances, the hull would need to be heated. In warmer weather, cooling the hull to the dew point of water at the current ambient pressure aids the formation of larger droplets. The next step in cloud mining is to tilt the lightcraft to a negative angle of attack. The ion guns are used to charge the forward water droplets, and the Maglev lander is positively charged in the ship's thyroidal center, and the now negatively charged water ions are pulled into the ship. The water is then softened, deionized, and distilled. It is transported out to the water storage tank located along the outer rim of the craft. At an average velocity of 20 m/s, which is approximately the most efficient speed for cloud mining, it takes close to 3 hours to take on 2400 kg of water. In many cases, this is a relatively long time. For this reason, it is not encouraged to use cloud-mining techniques exclusively. A better approach might be to take on enough water to make a hyperjump to a remote and safe pond or lake. INTRODUCTION TO FLIGHT DYNAMICS DISC AERODYNAMICS The Lightcraft aeroshell is merely a lenticular disc with no traditional control surfaces to direct or stabilize its flight path. The absence of fins, and any other surfaces jutting out from the smooth lenticular surface is a direct consequence of design requirements for the space plasma shield. In the subsonic ion propulsion mode such surface irregularities would trigger massive corona discharges off these edges and prevent the envelope from charging up for flight; in space, the hull would not be able to reach the 200 million volts needed to reflect solar proton storms. Attachment of any physical control surfaces to the thin pressurized hull of the lightcraft would be extremely difficult. Such fins and stabilizing surfaces would compromise structural integrity during the high Mach number maneuvers for which the craft is designed. Due to the lack of control surfaces the lightcraft must instead rely on active thrust vectoring from its Ion, PDE, and MHD propulsion systems. FLIGHT DYNAMICS The real time interaction of lift, drag, and vehicle moments of inertia determine the flight dynamics of a vehicle. The response of the Lightcraft lightcraft to flight control inputs is modeled by a series of equations stored within its control computers. The Lightcraft's flight characteristics set it apart from all conventional aircraft, primarily in the following areas: Drag on the vehicle can be reduced at will, by using air-spike technology. The craft can accelerate at 200 Gs or more. The craft is able to fly in both vertical and lateral directions. The lenticular disc hull of the Lightcraft is unstable in lateral flight. STABILITY SUBSONIC FLIGHT REGIMEThe Lightcraft lightcraft is dynamically unstable in several flight modes, and is designed for outstanding maneuverability in subsonic as well as hyper-energetic flight regimes. With the aid of its 3 flight computers, and active thrust vectoring, the Lightcraft enjoys stable and controlled flight throughout its transatmospheric design envelope. The Lightcraft's ion propulsion system enables flight speeds up to 44 m/sec, whereas the pulse detonation engine (PDE) can quickly push the lightcraft supersonic. During calm atmospheric conditions at low subsonic velocities, the ion propulsion mode does not require gyroscopic stabilization. Hence the crew can remain on the bridge on the observation deck. This means that the lightcraft is capable of performing the low altitude flight maneuvers necessary for rescue or reconnaissance missions. STABILITY AND CONTROL (ION) The ion thrusters use electromagnetic fields to vector the engine exhaust. The lightcraft can be programmed to fly in any direction, without necessarily having to first pitch or roll. High winds are one of the adverse weather conditions most often faced by the lightcraft under the ion thrust mode. With partial buoyancy at sea level, the 20 m craft can be blown around by high wind gusts. Uncompensated, each gust can tilt or flip the craft, or throw it off course. The ion engines are capable of compensating for gusts up to 100 mph. Once the craft's sensors detect even a minute unintended change in either the crafts attitude or lateral position, the ion propulsion unit is used to compensate, by projecting the ion clouds at the necessary angles to maintain the crafts previous tilt and position. ADVERSE FLIGHT CONDITIONS Adverse flight conditions, whether natural or artificial, have always caused a variety of threats to flying vehicles. The lightcraft is no exception. The lightcraft faces difficulties from 2 forms of adverse conditions, those natural and those created by humans. Most commonly faced are the natural adverse conditions, such as rain, high winds, lightning storms, or poor visibility. Light rain and mists cause few problems for lightcraft operations in the ion propulsion mode when energized by a low power microwave beam. Beamed laser power, however, is not a viable option due to the extreme absorption and scattering loses. Heavy rains are to be strictly avoided. The cumulus-nimbus clouds that produce them may be impenetrable to the power beam, necessitating the use of on-board SMES power for short time periods. Unlike light rain, lightning storms are a major threat to the craft. The high positive charge on the surface of the craft during the ion propulsion mode causes it to attract lightning strikes. Besides the potential structural damage associated with lightning strikes, such a discharge could also temporarily kill thrust on a large surface of the lightcraft, causing it to suddenly dip. There is little protection against this threat except to avoid areas of active electrical storms. Fair weather cumulus clouds, rather than presenting an adverse condition, can actually be used to advantage by the lightcraft when in ion propulsion mode. By depositing negative charge into the base of the clouds, the lightcraft can actually reduce the power necessary for it to maintain flight or hover. (Such clouds do cause a problem for hyperjumps in that they must be evaporated, at the cost of a high-energy expenditure, before a hyperjump can be performed using the PDE and MHD engines.) GEOMAGNETIC TORQUING SUPERSONIC FLIGHT REGIMEThe lightcraft does have an alternative to its ion-propulsion mode for torquing, to maintain level flight, or to tilt the craft. By using the magnetic dipole created by the pair of rim super-conducting magnets, the lightcraft is able to pitch or roll inside the Earth's magnetic field, producing torque comparable to that of its ion thrusters. The magnitude of torque available is primarily dependent on the angle between the B-field and the craft's magnetic dipole. When accelerating beyond 100 mph through mach 1 in lateral flight using the PDE thrusters the lightcraft must be rotating in order to have intrinsic stability. In order for a spinning disc to maintain stable lateral flight, the pitch and roll rates and linear velocities must return to equilibrium when disturbed. This does not mean that the angle of attack or position of the lightcraft will stay at the same value. PITCH AND ROLL RATES (PDE) HYPERSONIC FLIGHT REGIMETheory application and component parts of the Pulsed Detonation Engine (PDE) were discussed earlier. A short quick review of the main concepts is needed to understand how the PDE thrusters are used for pitch, roll, and rotation. The PDE thrusters operate by a high- energy microwave beam transmitted from an orbital power station. This beam must be precisely aligned with the lightcraft axis (i.e. rectennas) in order for this engine to function properly. For stealth the microwave beam is pulsed at either sub-audible or at super- audible repetition frequencies. When this beam is received upon the rectennas, it is reflected to focus just outside of the lightcraft rim, where it triggers electrical air breakdown. Focal intensities are sufficient to produce detonations of up to 30 atmospheric pressure. This conducting air plasma is then vectored in every desired direction by application of electromagnetic fields emanating from the rim superconducting magnets. These thrust-vectored pulses are barely visible to the unaided eye, since they each last only about 1 ms. The PDE's main function as an air-breathing engine is to rapidly push the lightcraft through Mach 1, jumping it into supersonic speeds (a hyperjump). To initiate an axial hyperjump the PDE thrusters sequentially fire all around the lightcraft rim, creating a uniform exhaust flow, which is vectored down. The plasma cloud can just as easily be vectored up, creating a downward thrust. In a maximum performance maneuver the Lightcraft can jump a few kilometers in 1-2 seconds. Aside from rapid accelerations in the axial and lateral directions, the PDE can be used to hover, pitch, roll, and spin the lightcraft. A pitch up or rolling maneuver necessitates producing a torque in the desired direction. The pulses are quick and discrete; hence, the lightcraft can sharply torque to most any attitude in a milli-second. To torque the lightcraft in the desired direction, the PDE exhaust is vectored by manipulating the electric currents carried in the upper and lower rim superconducting magnets. This distorts the magnetic fields producing a variable geometry magnetic nozzle to direct the expanding air plasma as necessary. To pitch counterclockwise, the upper superconducting magnet is held at a higher current than the lower magnet; this vectors the plasma exhaust down. And pitches the lightcraft down. The opposite coil currents produce a clockwise torque on the lightcraft. Finally, the PDE thrusters can be used to induce lightcraft rotation. By detonating the thrusters in sequence around the lightcraft, oblique, rotating, detonation wave fronts form around the lightcraft rim. Gradually the spiralling air around the rim expands and the friction forces transfer angular momentum to the lightcraft, causing it to spin. To accomplish MHD spin augmentation, the rectennas extract some fraction of the incident microwave beam pulses for conversion into electric pulses, which is delivered to the rim electrodes. The most fundamental aspect of the lightcraft, which makes transatmospheric flight to space possible, is the air spike linked to an annular MHD slipstream accelerator. A central laser beam is used to create this air spike. The air spike is formed when energy from the focused laser beam causes air to be radial driven out of the vehicle's path and pushed into the annular inlet located outside the rim of the lightcraft. In the process fore-body drag, and heat transfer are greatly reduced; also the propulsive efficiency of the MHD accelerator is increased. The electrical energy required by the MHD engine comes from two rectifying antennas located aboard the lightcraft. These 35 GHz rectenna arrays can deliver up to 9 GW of electric power to the engine. The biggest advantage of the air spike technology is that the lightcraft can be streamlined without a mass penalty, which is an extremely important issue for transatmospheric vehicles.RE-ENTRY AND AEROBREAKING METHODS The major mission parameter that defines the Lightcraft Lightcraft geometry is its capability for transatmospheric flight. The vehicle is designed to transport its crew safely around the Earth, as well as, between the lunar surface and Earth. This section deals with the re-entry and aerobraking legs of these journeys. As it comes upon the Earth's atmosphere, the vehicle reorients itself to achieve the proper angle of incidence. Because of the tremendous speed at which the craft enters the atmosphere, it must either decelerate under great G loads or find an alternative method that will allow it to gradually reduce speed. The Lightcraft uses 3 different approaches in resolving this difficulty. AERO-BRAKING The principle of aero-braking was first put to practical use by the early space exploration efforts. The space capsules of the era had a parabolic under-side, similar to that of the lightcraft, which acted as a heat shield. Upon re-entry, the capsule was orientated to create a strong normal shock wave across the bottom hemispherical surface of the craft. This "foot-print" generated a tremendous amount of drag, and thus decelerated the vehicle rapidly. However, the lunar Lightcraft's re-entry velocity can be up to twice that of the Apollo space capsules. Aero-braking alone does not allow the lightcraft sufficient flexibility for a safe recovery. Three alternative options are to use a different flight profile, flight magneto-hydrodynamics, or a powered re-entry. SKIP TRAJECTORY The first solution is a flight profile known as the "skip trajectory". Any vehicle with adequate lift that re-enters the atmosphere may use one or more passes through the atmosphere in order to reduce its initial kinetic energy. After the initial lost of velocity, the lightcraft may use the lift generated by its body to "skip" out of the atmosphere. Once outside of the atmosphere, the vehicle will gradually lose lift and drop back into the outer atmosphere. By repeating such a maneuver, the craft may safely re-enter the atmosphere without paying the penalty of great G loads. MAGNETO-AEROBRAKING One of the drawbacks associated with aero-braking is the rapid heat build up on the re-entry shield. Hypervelocity air comes in direct contact with the outer hull, the friction between the two causes the temperature of the hull to rise rapidly. This results in a construction of a heat resistant hull or a need for a heat-dissipater with great capacity, both of which pays dearly in weight penalty. Kartrowitz first demonstrated the concept of flight magneto-aerodynamics in the 1950's, discovering that a magnetic field has a great effect upon the re-entry bow shock. A magnetic field interacts with hypersonic air plasma surrounding a re-entry vehicle to push the shock wave away from it. The Lightcraft Lightcraft takes the full advantage of this principle upon its re-entry. By charging the two superconducting magnets along its rim, a powerful 2 Tesla magnetic field forms around the vehicle. This field pushes the oblique shock away from the hull. This prevents the heated hypersonic air molecules from coming into direct contact with the craft, and thereby alleviates the re-entry heating problem. POWERED REENTRY In sub-orbital flights around the Earth for the surveillance/rescue mission, the Lightcraft may require a maximum performance decent to low altitude hover. In this "powered re-entry" mode the lightcraft enters the atmosphere with lateral flight orientation with the Air Spike and MHD slipstream accelerators energized. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
sâmbătă, 20 noiembrie 2010
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