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The film-cooling and infrared radiation analysis of a high-performance aero-engine nozzle wall is the key problem in developing a vector propulsion technology. This study adopts a narrow band model to investigate the cooling and radiation of a vectoring nozzle and, in particular, to compute the gas spectral characteristic in infrared band. The radiative heat transfer between the hot gas and the wall...
The Thermal InfraRed Sensor (TIRS) instrument was launched into space on board Landsat 8 in February 2013. This instrument was added to Landsat 8 to measure water evaporation and transpiration as well as provide two thermal infrared bands to complement the optical suite. TIRS has a refractive telescope which focuses a light onto a focal plane cooled to 43K with a two-stage cryocooler. This paper will...
Star trackers must be calibrated prior to flight so that they can make accurate measurements of star positions within the instrument field of view. This calibration is often performed in atmosphere and once the sensor is launched, it is not uncommon to observe a small shift in some of the calibration parameters. To maximize sensor performance, these parameter values must be corrected to better match...
The growing interest in the area of nano-satellite development has escalated in the recent years. Space agencies and private industries have started developing nano-satellites for more serious missions in the areas of Space Operations, remote sensing and Space Research. The sudden increase in the number of nano-satellite missions has led to a challenge in frequency coordination, this has led to investigating...
Since the last two decades, aerospace agencies around the world have started planning Space-based Solar Power Systems (SSPS) as an alternative power source [1]–[9]. The use of Space Shuttle Orbiter type re-usable launch vehicles will enable the completion of this project in a limited time span with economic feasibility. This would leave less time between successive launches, making it imperative that...
Link analysis is a system engineering process in the design, development, and operation of communication systems and networks. Link models that are mathematical abstractions representing the useful signal power and the undesirable noise and attenuation effects (including weather effects if the signal path transverses through the atmosphere) that are integrated into the link budget calculation that...
We present an assessment of various image thresholding and centroiding algorithms to improve star tracker centroiding accuracy at moderate slew rates (< 10°/s). Star trackers generally have arc-second accuracy in stationary conditions, however their accuracy degrades as slew rate increases. In dynamic conditions, blur effects add to the challenges of star detection. This work presents an image...
This paper reports on the results of attempts to reduce the positioning error of strap down inertial navigation system using attitude information obtained by star tracker. In this regard, the position error equations of different channel in inertial navigation are modeled and error share of each sensor in position and attitude determination drifts are investigated. In continue celestial navigation...
Flight simulators with a physical mock-up are dependent on the aircraft type and have high costs. In order to overcome high cost issues, a generic virtual reality flight simulator is designed. Virtual buttons are used without a physical mock-up to make the virtual reality flight simulator independent of the aircraft type. The classic virtual hand metaphor is employed to interact with the virtual objects...
In order to provide for the safe integration of unmanned aircraft systems into the National Airspace System, the control and non-payload communications (CNPC) link connecting the ground-based pilot with the unmanned aircraft must be highly reliable. A specific requirement is that it must operate using aviation safety radiofrequency spectrum. The 2012 World Radiocommunication Conference (WRC-12) provided...
A spacecraft's hull has an upper limit on the amount of deformation it can withstand due to accelerating forces, a limitation often defined by the hull's composite material's Young's Modulus. This upper limit on the tensile and compressive forces that deform the material beyond its breaking point can be elevated with a modified Young's Modulus through the application of a piezoelectric material. When...
A balloon-borne Acousto-Optic Tunable Filter (AOTF) hyperspectral imager is ideally suited to address numerous outstanding questions in planetary science. The spectral agility, narrowband wavelength selection, tolerance to the near-space environment, and spectral coverage afforded by AOTFs would enable investigations not feasible from ground-based facilities. A notional AOTF imager design includes...
Correct track-to-track correlation is a key component of multi-sensor tracking and fusion. Some tracking systems provide full covariance only upon request, making the already difficult problem of multi-sensor track correlation even more difficult. To improve the correctness of correlation results involving track updates from such systems that contain state data without covariance, an estimated covariance...
CubeSat is a nanosatellite platform that provides access to space for small payloads. It is an attractive solution for space exploration missions as it reduces cost and development time. However, size constraints restrict the surface area for solar panels and thus the generated power. The efficiency of the power condition modules of the electrical power system (EPS) is a relevant feature in the design...
For the past several years, NASA Goddard Space Flight Center's Flight Projects Directorate (FPD) spearheaded the Business Change Initiative (BCI) to improve program planning and control practices to enhance cost and schedule performance. One outcome of the BCI is a renewed emphasis on schedule in the form of a directive to plan, assess, and measure schedule performance. A guideline with accompanying...
In September, 2013 the BRRISON mission suffered an anomaly resulting in a total loss of science data for the duration of flight. The Balloon Observation Platform for Planetary Science (BOPPS) mission is in essence a re-flight of the BRRISON mission. The BOPPS mission was designed to study multiple comets and other planetary bodies as well as demonstrate a fine pointing system. The performance of this...
The CubeSat Proximity Operations Demonstration (CPOD) mission led by Tyvak Nano-Satellite Systems will demonstrate rendezvous, proximity operations, and docking of two 3U CubeSats. The CPOD program passed CDR in March 2014 and has since progressed to flight vehicle production and test. Tyvak developed a unique relative navigation payload that includes delta GPS, inter-satellite link with radio ranging,...
Operating a world-renowned space flight mission portfolio under tight policy, fiscal scrutiny, and increased competition makes open communication, visible performance data, and streamlined processes challenging. To respond to these challenges and meet cost and schedule commitments, Goddard Space Flight Center's Flight Projects Directorate employed a Business Change Initiative (BCI) to infuse a series...
The Ionospheric Connection Explorer (ICON) is a NASA Heliophysics Explorer Mission designed to study the ionosphere, the boundary between Earth and space. This region, where ionized plasma and neutral gas collide and react, exhibits dramatic variability that affects space-based technological systems like GPS. The ionosphere has long been known to respond to space weather drivers from the sun, but...
It is common practice to write English-language “shall” statements to embody detailed software requirements in aerospace software applications. This paper explores the use of the UML language as a replacement for the English language for this purpose. Among the advantages offered by the Unified Modeling Language (UML) is a high degree of clarity and precision in the expression of domain concepts as...
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