Search Results

Water recovery is essential for long-duration space exploration transit and outpost missions. Primary stage wastewater recovery systems partially satisfy this need, and generate concentrated wastewater brines that are unusable without further processing. The Enhanced Brine Dewatering System (EBDS) is being developed to allow nearly complete recovery of water from Lunar Outpost wastewater brines. This paper describes the operation of the EBDS and discusses the development and testing of the major functional materials, components, and subsystems, including the wastewater brine ersatz formulations that are used in subsystem testing. The assembly progress of the EBDS full system prototype is also discussed, as well as plans for testing the prototype hardware.

Typical design challenges for Unmanned Aerial Vehicles (UAVs) require low aerodynamic drag and structural weight. Both of these requirements imply that these aircraft are considerably more flexible than conventional aircraft and their stability analyses are more complex since they require models unifying rigid body and elastic dynamics. This paper aims to built such a model for a generic UAV. The model is then used to address stability in terms of divergence and flutter.

It is estimated that operating continuously on a B20 fuel containing the current allowable ASTM specification limits for metal impurities in biodiesel could result in a doubling of ash exposure relative to lube-oil-derived ash. The purpose of this study was to determine if a fuel containing metals at the ASTM limits could cause adverse impacts on the performance and durability of diesel emission control systems. An accelerated durability test method was developed to determine the potential impact of these biodiesel impurities. The test program included engine testing with multiple DPF substrate types as well as DOC and SCR catalysts. The results showed no significant degradation in the thermo-mechanical properties of cordierite, aluminum titanate, or silicon carbide DPFs after exposure to 150,000 mile equivalent biodiesel ash and thermal aging. However, exposure of a cordierite DPF to 435,000 mile equivalent aging resulted in a 69% decrease in the thermal shock resistance parameter.

Early development of wastewater and brine processing equipment must rely upon ersatz formulations because authentic urine and hygiene water are variable in composition, difficult to acquire in quantity, and have limited storage life. Previous wastewater ersatz formulations (e.g. Verostko et al, 2004) were designed for chemical fidelity, to match the elemental ratios and VOC profile of defined blends of wastewater components. This paper presents an alternative spreadsheet approach to brine and wastewater ersatz formulation by combining “building block” recipes in user-selected ratios and accounting for compositional shifts upon evaporation.

To investigate the flammability of human hair, a series of normal and microgravity flame spread tests over human hair were performed in a low-speed flow tunnel to simulate spacecraft ventilation flows (∼20 cm/s). The tunnel atmosphere pressure and oxygen concentration was varied over the range of anticipated exploration atmospheres (21–34% O2 in N2, 8–14.7 psia). While hair is marginally flammable in air, spreading upward but not downward, it burns extremely well at or above 30% O2 in any direction or g-level. The spread is characterized by a quick spread over the surface ‘nap’ or ‘frizz’, followed by continued bulk burning. Two hair ‘styles’ were tested — short hair and long hair — and style does not seem to affect initial nap spread significantly. Opposed and concurrent nap spread rates are similar in 0g under comparable conditions. Oxygen concentration has a strong effect on flame spread rates.

It is well known that the drilling industry is a diverse industry with huge power needs for drilling deep wells. This paper discusses the drilling industry in general and the future need for HT power electronics to enable such activities as tractor drive drilling of deep horizontal wells. The discussion is geared at applications for drilling within the earth at ambient temperatures of 150°C and above.

In order to support effective recycling of resources in a bioregenerative life support system (BLSS), the processing of inedible agricultural wastes into edible food products must be included. The process of converting agricultural waste into usable food resources is called secondary food production. Secondary food production offers a way to reclaim part of the energy and nutrients already sunk in inedible biomass, thus increasing the efficiency of the BLSS and crop harvest index. However, multi-step processes and lower yields and acceptability have made some secondary food production processes in the past problematic and costly. This paper presents preliminary process descriptions for secondary food products which are likely to be cost effective and well accepted: sugar syrup prepared from biomass hydrolysate, single cell oil produced from biomass hydrolysate, and Pleurotus mushroom fruit bodies grown on recalcitrant biomass and unused substrate.

A prototype packed bed convective dryer has been studied for use in an energy-efficient closed air-loop heat-pump drying system for astronaut cabin waste. This paper presents a transient continuum model for the heat and mass transfer between the air and wet ersatz trash in the cylindrical drying vessel. The model is based on conservation equations for energy and moisture applied to the air and solid phases and its formulation includes the unique waste characteristic of having both dry and wet solids. It incorporates heat and mass transfer coefficients for the system measured on an ersatz trash in the dryer vessel, and experimentally determined moisture sorption equilibrium relationship for the wet material. The resulting system of differential equations is solved by the finite-volume method as implemented by the commercial software COMSOL. The validated model will be used in the optimization of the entire closed-loop system consisting of dryer, condenser, and heat-recovery modules.

Brine dewatering by evaporation on porous media, and collection of wastewater evaporation condensates rich in organic carbon, both provide favorable environments for microbial growth, such as mold overgrowth of rayon wicks in the AES brine evaporation system, and bacterial biofilms on condensate-wetted surfaces. The mold growth reported on AES wicks by Campbell et al. (2003) has been identified by microscopic and molecular techniques as chiefly Chaetomium spp, most likely C. globosum, with minor occurrence of Penicillium, and other fungal species. Bacteria from the genus Bacillus was also isolated. A stable bacterial consortium dominated by three species was recovered from initially-sterile glass surfaces wetted with sterile Biological Water Processor Effluent Ersatz (Verostko et al., 2004) and exposed to humidified air over a period of one week. The species were identified as Enterobacter aerogenes, Microbacterium foliorum and Pseudomonas putida by 16S rDNA sequencing.

The continued availability of leaded specialty aviation gasolines remains as an item of crucial importance in the near-term future of general aviation; however, the development of new piston engines capable of operation with other transportation fuels available in large pools is considered an indispensable element in the long-range survival of the industry. This paper offers a road map that while allowing the continued utilization of the current fleet of piston aircraft, sets the stage for a transition to new piston powerplants and associated aircraft, compatible with widely available transportation fuels such as motor gasoline based aviation fuels for the lower and some medium performance aircraft, and aviation turbine fuels for the balance of medium and high performance airplanes.

An outer loop guidance architecture was designed to control autonomous aerial refueling mission from the trail aircraft side. The design utilized bank, yaw rate, velocity and climb rate commands implemented using a previously developed adaptive trajectory concept. The concept was based on position error feedback that was used to control trail aircraft overshoot and tracking about the lead aircraft refueling point. To demonstrate this application, an open loop linear trail aircraft model at a given flight condition was selected. Inner loop control laws were designed using Linear Quadratic Regulator feedback controller and Balanced Deviation theory. The outer loop guidance architecture was then added to implement the application. The performance of the system was then evaluated for a selected position error, and disturbance.

Wet cabin trash, including food residues, moist hygiene wipes and wet paper towels, poses two problems on long term space missions: first, the generation of odors and potential health hazards by microbial action (spoilage); second, the diversion of water from the available recovery loops. We have developed an energy-efficient closed air-loop heat-pump dryer to remove moisture from the wet material. Circulation of hot air can pasteurize the trash in the original bag without water recovery. In drying mode, a gravity-independent Porous Membrane Condensing Heat Exchanger (PMCHX) traps condensate to be passed to the water recovery system. The DRYER system is suitable for stabilization of wet cabin waste in an advanced life support system, and may be adapted to drying of crew laundry and water recovery from water-reprocessing brines.

The ideal internal-combustion crankshaft engine would burn all the fuel near top center without detonation, then expand the whole charge until exhaust Both events are impossible with current piston engines. The Hydrocycle Rocket Piston Engine concept employs a free piston in the head of a two-stroke-cycle engine. Combustion between the crank piston and the free piston allows direct conversion of combustion fluid expansion to hydrostatic fluid flow and accumulator gas compression with perfect timing and minimum thermal and mechanical losses. An infinitely variable, radial hydrostatic motor gives the driver smooth, gas-cushioned acceleration and stepless performance. Maximum economy is attained since the driver is forced to run the engine at optimum minimum speed to match road load oadin all traffic conditions.

Drying is an important process, ubiquitous on earth, and in space applications it is an unavoidable aspect of advanced life support technology. We analyze several solid and liquid waste treatment processes that involve drying as a primary operation and consider factors such as energy use, volume, mass, crew time upstream relief and downstream burden. The entry points of resources such as electrical energy, thermal energy, mass influent and effluent and crew time are discussed in the context of a common drying schematic, compared using generalized flow diagrams, and a table is provided to grasp the relative magnitudes.

In the future, it will be possible to manufacture very small, robust machines, which may be attached to the surface of a wing allowing the classic boundary condition of “no-slip” to be altered at will. It is also possible that the heat transfer through the wing surface can be controlled. This paper reports an investigation into the possible benefits to aerodynamics that will occur if such machines become available. It is found that imposing an isothermal wing surface can increase the lift drag ratio of wing at transonic cruise and allowing slip at the surface can have the same effect. Both these effects are additive. It is found that control of heat transfer on a wing at hypersonic wing can act as a control device, comparable to that due a moderate flap deflection.

This paper deals with a conceptual aircraft cargo loader “that can do everything” commonly referred to as The Super Loader. The Super Loader is intended for use at air terminals to transport loads such as palletized cargo, containers, wheeled vehicles, shelters, and airdrop platforms from the storage docks to the military and civil aircraft, and vice versa. The loader may be described as a self-propelled, air transportable (in a C-141, C-17, C-5) 60,000 lb lifting capacity, adjustable height vehicle that will load/off load all transport aircraft from a C-130 whose cargo deck is only 3 feet, 3 inches high to a B-747 whose main deck upper limit is about 18 feet high. The Super Loader must also service the lower lobes of wide-bodies and main decks of narrow-bodied aircraft like the DC-8 and B-707. In brief, this loader will be required to interface with both civil and military cargo systems, present and future.

Of the many research approaches investigated over the years to measure the lubrication properties of aviation turbine fuels, the Ball-on-Cylinder Lubricity Evaluator (BOCLE) has emerged as the most significant test. BOCLE was originally a lubricant research device modified for low viscosity jet fuel when the Air Force encountered fuel control problems in 1965 with JP-4. It proved to be capable of detecting the presence of additives such as corrosion inhibitors which improve boundary lubrication properties and also the absence of natural lubricity agents in highly refined jet fuel. The Coordinating Research Council carried out several programs to investigate test variables such as cylinder type, humidity control and load. A semi-automated version using Falex test rings has now been commercialized and is being used to test fuels from aircraft experiencing abnormal pump wear and fuel control hang-up.

The aerodynamics of the STOL aircraft can experience significant changes in proximity to the ground. A review of the existing data base and methodologies has been made and the results of that review are presented in this paper. The existing data show that in ground proximity the STOL aircraft will generally experience a reduction in the lift component regardless of the lifting configuration. Those configurations with integrated power and lift systems will have an additional effect of ground induced aerodynamic changes. This paper will discuss the existing data base and the deficiencies of that data base.

A novel two stroke cycle diesel engine is evaluated as a general aviation aircraft powerplant. Two certificated spark-ignited gasoline reciprocating engines are also evaluated in the same aircraft. The evaluation of aircraft propulsion performance considered only the effects of altered powerplant parameters on the range of an aircraft having a fixed gross weight and payload cruising at a given lift/drag ratio. Thermodynamic analysis finds the diesel engine can have a sea level power rating exceeding the 10,000 foot cruise power requirement by 55% with nearly equal specific fuel consumption, a low engine speed and a modest cylinder pressure. It uses a single-stage, radial turbocharger without intercooling or auxiliary mechanical scavenging. The diesel engine can significantly increase the range of a particular airplane now powered by a certificated turboprop engine. The candidate gasoline engines could not equal the turboprop-powered aircraft performance.

Two-stage-to-orbit (TSTO) conceptual-level vehicle designs were evolved by the Lockheed-California Company in the mid-1960s. The purpose was to provide a vehicle-systems-level basis for assessing the payload performance potential of a new class of Stage 1 propulsion systems: combined-cycle airbreathing/rocket engines. TSTO configurations were also established as conventional all-rocket and all-airbreathing engine comparison cases. These vehicle designs and their operating characteristics, along with their orbital payload-delivery capabilities, are presented for consideration by today's space transportation systems planning community.