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Characterizing the interface bond of thin-ply composites is important for assessing the overall structural integrity. Due to the flexibility of thin composite laminates, it is not feasible to carry out mode I double cantilever beam (DCB) and mode II end notch flexure (ENF) tests, due to the large geometric changes undergone during testing. To reduce the compliance during testing, thick aluminum substrates are bonded to the two free-surfaces of the test laminates. DCB and ENF tests are specifically carried out in this configuration. A specific glass fiber plain weave interface of a 7-ply composite structure is tested. µCT imaging shows the presence of periodic voids of size scales of 200 µm, and local delaminated regions of 0 . 7 − 5 . 6 mm. The former is attributed to capillary effects from the glass tows, while the latter is due to insufficient resin flow during the two-cure manufacturing process.

Ultra-thin TRAC booms are a promising technology for large deployable structures for space applications. A manufacturing process producing composites TRAC booms with flange thickness as low as 53 μm is proposed. Coiling behavior around hub with radii ranging from 19.1 mm to 31.8 mm is studied both experimentally and through finite element simulations. Due to the thinness of the TRAC boom, a buckle appears in the inner flange, in the transition region from the fully deployed to the coiled configurations. Material failure is observed at this location, and this correlates well with stresses computed in simulation, coupled with the fiber microbuckling failure criterion. Reducing the thickness, either by changing the laminate or by improving the manufacturing process, is shown to reduce stresses, allowing coiling around smaller hubs without material failure.

Metallic triangular rollable and collapsible (TRAC) booms have deployed two Cubesatbased solar sails in low Earth orbit, making TRAC booms the most popular solar sail deployment method in practice. This paper presents some concerns and solutions surrounding the behavior of these booms in the space thermal environment. A 3.5-cm-tall, 4-meter-long TRAC boom of Elgiloy cobalt alloy, when exposed to direct sunlight in a 1 AU deep space environment, has a predicted tip motion of as much as 0.5 meters. Such large thermal deflections could generate unacceptable distortions in the shape of a supported solar sail, making attitude control of the solar sail spacecraft difficult or impossible. As a possible means of mitigating this issue, the thermal distortion behaviors of three alternative material TRAC booms are investigated and compared with the uncoated Elgiloy baseline boom. A tenfold decrease in induced curvature is shown to be possible relative to the baseline boom. Potential thermal distortions of the LightSail-A solar sail TRAC booms are also examined and compared, although inconclusively, with available on-orbit camera imagery.

ight management computers. Fast-time simulations of current-day trac levels in two regional airspaces under nominal weather conditions are simulated to evaluate the benet of modifying a conict resolution algorithm to select resolution maneuvers based on minimum cost. The study employs the use of a parameter to represent the relative importance of fuel burn price to delay price. Additionally, the price of fuel burn and delay relative to one another is varied from the nominal in order to illustrate the dierences in the algorithmic behavior should the delay or fuel price increase. Results show the lowest total operational cost occurs when the relative importance of delay to fuel burn price is equally weighted. Overall, minimizing fuel burn when selecting resolutions based on cost results in a lower operational cost than minimizing delay. The sensitivity of total operational cost to resolution types is presented. Implications of these ndings for advanced separation assurance concepts are discussed.

distribution, alleviate the demand-capacity imbalances, and thereby increase the throughput of the entire national airspace system. However, past research has mainly focused on en route airspace. In this paper, we propose a mathematical programming based algorithm for dynamic terminal airspace conguration. With the understanding of the current terminal airspace organization and terminal operations, we handle the altitude changes by vertical stratication, formulate the airspace sectorization problem as an optimization problem, include separation regulations, ight path requirements and geometric restrictions as constraints, and construct a mathematical program. By solving for its optimal solution, we generate terminal airspace sectors which can account for the major trac ows and accommodate the trac variations. A preliminary benet analysis is conducted to show the promising benets of the proposed algorithm.

control procedures to reduce human controllers tasks and thereby increase the airspace capacity. Therefore methods for evaluating safety of these automated ConOps are highly desired. In this paper, a new methodology is introduced for conducting safety analysis of such automated airspace ConOps. This methodology includes a multilayer framework to model the Conict Detection and Resolution (CD&R) mechanism for dierent ConOps and analyze the probabilities of primary and secondary conict that could occur as a results of executing primary conict resolution actions. The multi-layer framework is composed of Dynamic Event Trees (DET), fault trees, reliability block diagrams and Markov chains. We present the modeling framework and its application in performing safety-capacity trade-o analysis. Safety-Capacity analysis indicates how the probability of conict increases as a function of trac growth for dierent

Operation of unmanned aircraft in the United States’ National Airspace System is currently severely restricted, primarily due to the need to ensure adequate separation between manned and unmanned aircraft (UA). A particular problem in any conict avoidance algorithm is estimating where conicting trac is likely to be in the future. While most air trac spends a large percentage of its time in straight and level ight, maneuvers are still quite common and must be considered. Incorporating uncertainty in tracking algorithms is well established, but current methods primarily only consider uncertainty related to sensor errors and modeling errors. They do not consider the uncertainty of pilot decisions regarding maneuvers. The objective of this research has been to quantify the level of uncertainty in aircraft position due to pilot maneuvers and develop methods for incorporating that information into tracking and conict avoidance algorithms.

The Spot Release Planner (SRP) is an algorithm previously developed by the authors to reduce delay and congestion on the airport surface. The algorithm was developed to provide real time advisories to tower controllers. A Human-in-the-loop (HITL) simulation in April 2010 showed that the SRP reduced the average movement area delay of departure aircraft by 64%. The SRP is a two-stage algorithm that considers runway scheduling in the rst stage, and the rest of the ground movement, such as gate pushback and spot release, in the second stage. This decomposition of airport surface scheduling into two stages provides fast computational times and makes the SRP applicable for real-time decision making. However, the two stages also result in the given scheme being a heuristic for solving the complicated airport surface scheduling problem; no guarantees on quality of the obtained solution have been provided. This paper explores the quality of solutions obtained by the SRP and compares them with the optimal solution for airport surface trac. Simulations conducted for the East side of Dallas/Fort Worth International Airport (DFW) show that the SRP solutions are within 14s of the optimal solution for a detailed airport surface planner.

A class of strategies has been proposed to reduce contrail formation in the United States airspace. A 3D grid based on weather data is built and the cruising altitude level of aircraft is adjusted to avoid the persistent contrail potential area with the consideration to fuel-eciency. In this paper, the authors introduce a contrail avoidance strategy on 3D grid by considering additional operationally feasible constraints from an air trac controllers aspect. First, shifting too many aircraft to the same cruising level will make the miles-in-trail at this level smaller than the safety separation threshold. Furthermore, the high density of aircraft at one cruising level may exceed the manageable workload for the trac controller. Therefore, in our new model we restrict the number of total aircraft at each level. Second, the aircraft count variation for successive intervals can not be too drastic since the workload to manage climbing/descending aircraft is much larger than managing cruising aircraft. The contrail reduction problem is formulated as integer programming and the problem is shown to have the property of total unimodularity. Solving the corresponding relaxed linear programming with the simplex method provides an optimal and integral solution to the problem. Simulation results are provided to illustrate the methodology.

This paper discusses a novel approach to associate and rene aircraft track data from multiple radar sites. The approach provides enhanced aircraft track accuracy and time synchronization that is compatible with modern air trac management analysis and simulation tools. Unlike existing approaches where the number of aircraft in the radar data must be assumed, this approach requires no such prior knowledge. While commercial aircraft provide ID tags captured in the radar data in the form of Mode 3 transponder codes, general aviation often lacks such transponders, which precludes using the number of codes sensed to count the number of aircraft in the data. To meet this challenge, an approach to track an unknown number of unidentied aircraft using a clustering algorithm is proposed. The paper presents a method to relate aircraft between consecutive time frames and rene the trajectories of those vehicles. Experimental results from evaluating the algorithm and demonstrating its viability are provided.

A hybrid satellite and terrestrial system can achieve robustness even in the case of disastrous situations and has been attracting an attention these days. The STICS (Satellite / Terrestrial Integrated mobile Communication System) is one of the most promising hybrid satellite and terrestrial systems. In this paper, we discuss the enhancement of the STICS. A novel STICS architecture, a trac dynamic channel assignment scheme, and a fast

Robust schedule-based arrival management requires efficient recovery from off-nominal situations. This paper presents research on modeling off-nominal situations and plans for recovering from them using TRAC, a route/airspace design, fast-time simulation, and analysis tool for studying NextGen trajectory-based operations. The paper provides an overview of a schedule-based arrival-management concept and supporting controller tools, then describes TRAC implementations of methods for constructing off-nominal scenarios, generating trajectory options to meet scheduling constraints, and automatically producing recovery plans.

In this paper, we present preliminary results on the impact of GPS and ADS-B reported position on the performance of a novel conict/collision alerting algorithm primarially intended for General Aviation (GA). For this purpose, we analyze the dynamics of GA trac using 6 months of trac in the San Francisco bay terminal area and several representative airport trac areas. The observed standard proximity of GA aircraft to each other and their maneuvring dynamics indicate that existing collision avoidance systems such as TCAS would have unacceptably high nuiscence alarm rates for low altitude GA operations. We then present a novel collision alerting algorithm, based on ADS-B. This algorithm uses a buer zone, the Collision Airspace Zone (CAZ), around the target/intruder aircraft and alerts the pilot of the ownship aircraft of the predicted penetration of the CAZ by the ownship. The size of the CAZ is determined by the reported ownship GPS and target ADS-B position accuracies. Our analysis suggests that the CAZ should be a cylinder of radius 528 ft and semi-height 200 ft. This is very close to the traditional near mid-air collision cylinder dimensions (500 ft radius, 200 ft sem-height) . Simulations are presented which analyze the performance of the algorithm, in terms of detection time, as a function of the CAZ dimension.

ight paths, the other including the entire National Airspace System. Numerical results of this study show that the Link Transmission Model achieves a same level of accuracy as Large-capacity Cell Transmission Model in air trac prediction , and the computational eciency is signicantly improved with an equally optimal solution in air trac optimization.

This paper describes a Multi-Purpose Cockpit Display of Trac Information (MPCDTI), which integrates core functional capabilities that can be combined in various ways to perform ADS-B In applications in the NextGen environment. The MPCDTI is dierent from other CDTIs in that it packages the capability to manage multiple applications within a single piece of equipment. Four key elements of the MPCDTI have been dened: elemental functions, simultaneous enablement, automatic algorithm selection, and output arbitration. These elements allow compatible functions to be enabled and prevent the MPCDTI from outputting infeasible or conicting guidance to the ight crew. The objectives of this paper are to present the key features of the MPCDTI and also to suggest a functional approach for developing MPCDTI and future application performance requirements.

The New York airspace is the most congested in the U.S. air transportation network. Increasing capacity in this area is critical to ensure the balanced growth of trac across the U.S. This analysis quanties the potential for improvement in airspace capacity by measuring the capacity envelopes for six dierent congurations of the New York airspace and comparing them to the maximum observed capacities at each airport. The comparison shows that the total airspace capacity is at least 20% lower than the combined capacity of the four airports. This nding suggests that if the New York airports could operate without any interactions, substantial capacity gains could be achieved. These gains can be realized by optimizing the delivery and acceptance of trac to and from these airports. The increased precision of navigation technologies to be used in the Next Generation Air Transportation System (NextGen) will enable some of this additional capacity to be attained. The study also considers some examples of additional capacity gains that could be realized by changing approach and departure procedures to reduce inter-airport interaction using NextGen technologies. Such procedural changes can attain large additional capacity benets by allowing each airport to operate close to their decoupled capacity.

costly. The key is therefore to establish an accurate assessment of the victim’s state and this is currently tributary to the presence onboard of a medical doctor and equipment. We propose in this contribution a network trac model for the deployment of an inight, satellite based telemedicine service. The purpose of the terminal is to support accurate remote assessment using a cabin crew member as operator. This contribution also includes an estimation of the network resources required for running the service.

*TRAC is a route/airspace design, fast-time traffic simulation, and analysis tool for studying NextGen trajectory-based operations. TRAC has been updated to enable users to readily specify trajectory-modification options, referred to as ‘degrees of freedom,’ for controlling aircraft flying Area Navigation/Required Navigation Performance routes. This paper describes the graphical specification scheme and presents example use cases drawn from research on super-density terminal-area operations. The examples illustrate how the capability has been integrated with other TRAC simulation and analysis capabilities, and highlight some implications of employing certain trajectory-modification options in candidate operational concepts.

International audience; In this paper we present our approach toward the validation of new aeronautical applications in satellite communication environment through the use of link emulation and exogenous traffic generation. We describe the hardware and software components of the satellite emulation platform we have implemented for a project named CAPITOLE that has been initiated through the Aerospace Valley world competitiveness cluster. After a short presentation of the overall project, a list of hardware and software components used is given and detailed. Lastly, we explain how the platform itself is validated through network metrology techniques.

A Variable-Length Link Transmission Model for Tra c Flow Management (TFM) is developed and implemented. The model is derived from the spatial reduction of a Multicommodity Large Capacity Cell Transmission Model for en route tra c. Like the Cell Transmission Model, our Link Transmission Model is based on an aggregation of historical air tra c data, and minimizes total aircraft ight time by selecting aircraft holding and routing decisions. Compared to the Cell Transmission formulation, the Link Transmission formulation decreases the number of variables by a factor of eight without impacting the accuracy of the model. Also, solving and processing time is reduced by up to 90%.

TRAC is a route/airspace design, fast-time traffic simulation, and analysis tool for studying NextGen trajectory-based operations. This paper describes trial-planning and scenario-generation capabilities recently added to TRAC to support analyses of superdensity operations in terminal-area airspace. The trial-planning capability enables researchers to analyze control options and how they are affected by uncertainties, while the scenario-generation capability is geared toward analyzing how terminal-area route structures and control strategies can support super-density operations. The paper describes how the two capabilities are implemented and gives examples of analyses they support.

The ramp area is a complex portion of the airport, often congestion and interactions between aircraft limit ecient ows for arriving and departing aircraft. Aircraft taxiing trac is constrained by minimum aircraft separation, and geometry of airports. In this paper, we present a new approach to assign gate to minimize ramp congestion and propose a simulation model to predict the operation time within the congested ramp. The optimized gate assignment reduces ramp operation time up by 50%. In addition the estimation of ramp operation times is more accurate when applying the optimized gate assignment algorithm.

This paper describes a novel method for finding optimal trajectories for vehicles constrained to avoid one another. The key property of the method is that it provides globally optimal solutions while retaining the full nonlinear dynamics model. Applications for the method include guidance of Unmanned Aerial Vehicles (UAVs), air trac control, and robot path planning. The core concept is the direct application of branch-and-bound optimisation, to find guaranteed, globally-optimal solutions to non-convex problems. This extends the work using nonlinear branch-and-bound optimiation for static obstacle avoidance where significant solve time savings were found against a conventional Mixed-IntegerLinear-Programming (MILP) approach. The proposed method uses the branch-and-bound approach for multi-vehicle avoidance problems by first, using a geometric branching strategy based on the decision for a pair of vehicles to pass one another clockwise or anticlockwise; and second, solving the resulting subproblems by constructing solutions on each chosen “side” and using them to initialise an interior point optimisation. Two alternative methods of constructing initial solutions for initialising the interior point optimisation are proposed and compared. Both methods are then compared to existing Potential Fields and MILP methods demonstrating a significant improvement on MILP solve times for problems with four or more vehicles.

We examine the tradeo between fairness and delay in air trac o w management and planning, using an M/D/1 queue bank model. To motivate our o w-based approach to studying fairness, we rst give several illustrative examples that characterize fairness (and performance in terms of delay/cost) in the current United State National Airspace System. We then pursue analysis and design of fairness, using the queuebank model. We nd that optimal allocations of capacity resources (with respect to average-delay measures) are unfair: much larger delays are imposed on minor o ws as compared to major ones at the optimum. Also, the fairness of the optimal allocation is shown to exhibit a dependence, albeit a weak one, on the congestion level. We then explore how much additional delay cost is imposed if a certain fairness level is imposed, and nd that signican t improvement in fairness can sometimes be achieved with moderate increase in cost. Finally, we briey note that the fairness issue studied here is analogous with the fairness concerns that arise in bandwidth allocation problems for communication networks, and suggest that further examining these commonalities may be illuminating.

This research proposes and analyzes an approach for predicting controller workload by predicting dynamic density. Most dynamic density formulations estimate workload with a linear combination of a set of dynamic density factors that describe the trac situation in a sector. The robust approach proposed here uses this linear structure and the available data to explicitly consider the relative levels of uncertainty in dynamic density factor predictions when predicting dynamic density. The benets of the robust approach are analyzed by using predicted and actual dynamic density factor data collected while playing back trac data in the Future ATM Concepts Evaluation Tool. Results indicate that the robust approach produces errors that are more than an order of magnitude smaller than those produced by a simple approach that ignores factor prediction uncertainties. However, other approaches achieve lower prediction errors than the proposed robust approach.

The progression of aviation has led to the strong desire to integrate unmanned aerial systems into the national airspace system. In order for unmanned aircraft to occupy national airspace concurrently with other aircraft, the Federal Aviation Administration regulations require that unmanned aircraft \see and avoid" other air trac to the same extent as a human pilot. The focus of this research is to explore the use of two collaborating unmanned aircraft working together to ensure separation from other air trac using measurement data obtained from optical sensors. The system is designed for use with small, light-weight aircraft that are operated below 10,000 feet mean sea level. Computer simulation was used to explore the implementation of a control strategy for positioning the collaborating aircraft to maximize the accuracy of their estimates of interfering trac locations and minimize the potential for conicts while ying to a specied location. The performance of the range estimation algorithm was explored as well as the system reliability while subject to multiple interfering aircraft and operational constraints such as ownship maneuverability. A comparison with two other possible formations was conducted to determine how the proposed method performed in both range estimate and miss distance of conicting air trac.

Given thousands of flights in a capacity-limited airspace, finding optimal scheduling strategies that minimize delay costs is a computationally difficult task. In this paper, stochastic search techniques are applied to this fundamental Traffic Flow Management problem. Genetic algorithms and simulated annealing rely on searching the solution space in a manner much different than traditional optimization methods. These stochastic search techniques are compared to an integer linear programming model previously described in the literature. The runtime and aircraft schedules resulting from each model are analyzed. Results indicate that the integer programming model finds the optimal schedule faster than the next best technique, simulated annealing. In the presented experiments, solving the same problem with different simulated annealing solvers in parallel, a quality solution (within 5% of optimality) can be found in most cases. With roughly the same number of computations, simulated annealing reached a better solution than the genetic algorithm in 6 out of the 9 scenarios tested.

A greedy heuristic algorithm for combining under-utilized airspace sectors to conserve air trac control resources is suggested and analyzed. Simulations using historical air trac data suggest that systematically combining under-utilized airspace sectors within centers can lead to signicantly fewer sectors and therefore a more ecient utilization of air trac control resources. The eciency gains are more modest when sectors are only allowed to combine with sectors in the same controller area of specialization. Parameters can be adjusted to ensure that this approach to combining sectors works well with operational procedures as well as to trade o eciency and the likelihood of sectors exceeding their capacity. Quantitative analyses show that the likelihood of sectors exceeding their capacities can be decreased eectively without signicant sacrices of eciency gains by changing the minimum capacity gap parameter.

In this paper, a hierarchical, hybrid framework is proposed for representing and analyzing the interaction of multiple aircraft operating under dierent collision avoidance and separation assurance regimes. The model is broken down by the three dierent collision avoidance regimes: immediate collision avoidance, midterm collision avoidance and separation assurance. These schemes are classied by the time scale in which they operate. Even though each collision avoidance scheme is independently safe, when they are combined the entire system can become unsafe. In this paper, backwards reachable sets are used to analyze the interaction between the immediate and midterm collision avoidance schemes resulting in provable safety conditions. The vertical reachable set is also used to analyze the Trac Alert and Collision Avoidance System (TCAS), a specic immediate collision avoidance scheme.

This paper presents an overview of TRAC, an integrated graphical design, fast-time simulation, and analysis tool to support NextGen concept development research. It describes typical NextGen research activities together with the TRAC functionality that supports them. The paper presents screen snapshots that illustrate how TRAC can be used to help understand current airspace, route structure, and operations from an air traffic control perspective, rapidly prototype new airspace and route structures, generate traffic scenarios and conduct fast-time Monte Carlo simulations of NextGen concepts, and analyze human-inthe-loop simulation data.

En route air trac management is dicult and can benet greatly from decision support tools. This paper presents a study of the eciency and eectiv eness of two practical approaches to real-time scheduling algorithms: a simple greedy scheduler and a well-studied optimal scheduler. A subset (region) of the National Airspace System is isolated to perform optimization on a manageable portion of the airspace. The schedulers are tested on realistic data sets representing trac and conditions in the corridor between Chicago and New York area airports. In particular, the optimal scheduling of igh ts with both origin and destination in that corridor is considered, while reserving sucien t airspace for other air trac. In a majority of cases, the greedy method provides sucien t (often optimal) results, while under dicult trac and weather conditions, the optimal scheduler is worth the runtime requirements due to the inability of the greedy version to nd satisfactory solutions. Further benets of an optimal scheduler are demonstrated by incorporating the concept of equity or ‘fairness’ into the scheduling decision. Design choices in implementing equity amongst the various airlines are discussed and results demonstrating the utility of these choices are provided. Equity is easily implemented for the optimal scheduler but not the greedy, and does not require signican t additional run time. Ultimately, it is shown that an equity-aware decision support tool for delay optimization can be developed to run in real-time and can benet from incorporating more than one approach depending on the complexity of the scenario.

An Integer Programming formulation is developed for optimizing surface operations at Dallas-Fort Worth airport, with the goal of assessing the potential benefits of taxi route planning. The model is based on operations in the eastern half of the airport under the most frequently used configuration. The focus is on operational concepts that optimize taxi routes by utilizing dierent control points on the airport surface. The benefits of two dierent concepts for optimizing taxiway operations, namely controlled pushback and taxi reroutes are analyzed, for both current data and a projected data set with approximately twice the trac density. The analysis estimates that: (1) for current trac densities, controlled pushback would reduce the average departure taxi time by 17% without altering runway schedule conformance, while the benefits of taxi reroutes would be minimal; and (2) for high-density operations, controlled pushback would reduce the average departure taxi time by 18%, while incorporating taxi reroutes would reduce the average arrival taxi time by 14%. Other benefits analyzed for these control strategies include a decrease in the average time spent in runway crossing queues.

in the National Airspace System using an Eulerian description of the network with hyperbolic partial dierential equations. Existence and uniqueness (well-posedness) of a solution to the system of partial dierential equations on a network is established. Subsequently, an optimal control problem is studied with the junction coecients as control variables. We use a fully discretised adjoint approach and we implement it on a network with 16 links and 5 junctions created from the enroute high altitude jetways between the Oakland and Salt Lake City air trac control centers. The aircraft flows on the final link of the network with and without control are compared and the results demonstrate the eciency of the method developed in the article.

The safety of the igh ts, and in particular conict resolution for separation assurance, is one of the main tasks of Air Trac Control. Conict resolution requires decision making in the face of the considerable levels of uncertainty inherent in the motion of aircraft. We present a Monte Carlo framework for conict resolution which allows one to take into account such levels of uncertainty through the use of a stochastic simulator. A simulation example inspired by current air trac control practice illustrates the proposed conict resolution strategy.

The National Airspace System in its current incarnation is nearing its maximum capacity. The Free Flight initiative, which would alter the current system by allowing pilots to select more direct routes to their destinations, has been proposed as a solution to these problems. Allowing pilots to fly anywhere, as opposed to being restricted to planned jetways, greatly complicates the problem of ensuring separation between aircraft. In this paper we propose using cooperative, multi-agent negotiation techniques in order to eciently and pseudo-optimally resolve air trac conflicts. Our system makes use of software agents running in each aircraft that negotiate with one another to determine a safe and acceptable solution when a potential air trac conflict is detected. The agents negotiate using the Monotonic Concession Protocol and communicate using aircraft to aircraft data links. There are many benefits to using such a system to handle the resolution of air trac conflicts. Automating CD&R will improve safety by reducing the workload of air trac controllers. Additionally, the robustness of the system is improved, as the decentralization provided by software agents running in each aircraft reduces the dependence on a single ground based system to coordinate all aircraft movements. The pilots, passengers, and carriers benefit as well due to the increased eciency of the solutions reached by negotiation.

PMDIS: “Perceptual-Motor Deficits In Space (York University Toronto, Prof. Dr. Berry Fowler)” and TRAC: “Test of Reaction and Adaptation Capability (German Sports University Cologne, Prof. Dr. Ottmar Bock)” are experiments of an international space project. The experiments are conducted onboard the Space Shuttle (STS-115) and on the International Space Station (ISS). This paper elucidates the design of the main mechanical device on which the PMDIS/TRAC experiments are carried out; namely the PMDIS/TRAC table. The design of the table was driven by the following factors: experiment specific requirements rules and regulations related to manned space flights manufacturing technology and economic viability The result of the design process was a collapsible and modifiable aluminium table. The components of the hardware were manufactured using CNC technology.

A series of reduced-gravity two-phase flow experiments has been conducted with a boiler/condenser apparatus in the NASA KC-135 aircraft in order to obtain basic thermal-hydraulic data applicable to analytical design tools. Several test points from the KC-135 tests were selected for simulation by means of the COBRA/TRAC two-fluid, three-field thermal-hydraulic computer code; the points were chosen for a 25-90 percent void-fraction range. The possible causes for the lack of agreement noted between simulations and experiments are explored, with attention to the physical characteristics of two-phase flow in one-G and near-zero-G conditions.