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NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) mission was both a lunar science and a technology demonstration mission. The goals identified for LADEE were to determine the composition of the lunar atmosphere and investigate the processes that control its distribution and dynamics, and to determine whether dust is present in the lunar exosphere and reveal the processes that contribute...
Due to the Human Visual System (HVS) the response to well brightened images is frequency dependent. The Discrete Cosine Transform (DCT) - based compression schemes are capable of separating the perceptually significant information in an image from the information that the eye cannot perceive. Hence in image compression, DCT is most widely used transform. In this paper, an algorithm for compressing...
This paper introduces OpenASIM, an AFRL funded project to create an open source ASIM available under a LGPL license with two goals: 1) to solve compatibility issues in currently available ASIMs and 2) to provide the community with a tool to streamline the design and construction of spacecraft of any size. OpenASIM's performance and features rival other commercially available ASIMs. It has the advantage...
This paper presents the development of the attitude determination and control system design of the Cyclone Global Navigation Satellite System spacecraft. The CYGNSS constellation consists of eight small satellite observatories in 500 km circular orbits at an inclination of 35 deg released from a single launch platform. Each CYGNSS spacecraft will make frequent and accurate measurements of ocean surface...
Communication link and target ranges for satellite communications (SATCOM) and space-based sensors (e.g. radars) vary from approximately 400–1000 km for low earth orbits (LEO) to 35,800 km for geosynchronous orbits (GEO). At these long ranges, large antenna gains are required and most legacy systems use high gain reflectors with beams that are either fixed or mechanically steered. However, for some...
Astronauts experience important physiological adaptation to weightless environment, including bone loss, muscle atrophy, cardiovascular deconditioning, and vestibular disorientation. Physiological deconditioning will be even more challenging in future long-duration space missions, for example to Mars, in which astronauts will be exposed to microgravity for six to eight months before landing without...
In September of 2016, the OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith EXplorer) spacecraft will depart for asteroid (101955) Bennu, and when it does, humanity will turn an important corner in the exploration of the Solar System. After arriving at the asteroid in the Fall of 2018, it will undertake a program of observations designed to select a site suitable...
Space object image enhancement is an important problem in computer vision, which is also a fundamental issue for space observation. Instead of single image enhancement methods, we introduce a method based on intrinsic image de-composition by using an image sequence to solve the problem of space object image enhancement. We first capture several space object image sequences via ground simulation and...
This paper addresses the technical aspects of the sample return system for the upcoming Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) asteroid sample return mission. The overall mission design and current implementation are presented as an overview to establish a context for the technical description of the reentry and landing segment of the...
The E and B experiment (EBEX) is a balloon-borne telescope designed to measure the polarization of the cosmic microwave background with 8' resolution employing a gondola scanning with speeds of order degree per second. In January 2013, EBEX completed 11 days of observations in a flight over Antarctica covering ∼6000 square degrees of the sky. The payload is equipped with two redundant star cameras...
To model the status of collision of two fast moving objects in the field of space science and computer aided geometric design, one approach is to perform high-precision orbit and forward propagations of two objects, then compare the distance between them at closely spaced instants of time to determine the moment of closest approach, and then compute its minimum distance. The mathematical and physical...
This paper examines the performance of the Doppler Particle Filter (DPF) algorithm to locate a push-to-talk handset from the its radio frequency transmissions recorded on-board an aircraft. The technical challenge resides in the mathematical solution to solve for the stationary radio location based on the received Doppler shifted frequency measurements from an emitter with a non-stationary or drifting...
Numerical investigations on stratospheric airships of different tail configurations are conducted based on the Reynolds-averaged N-S equations and k-ω SST turbulent model in the condition of the same volume and total area of the tails. The influence of tail configurations on the force and moment characteristics as well as flow phenomena on both hull and fins are analyzed. In particular, the hull-fin...
Future human spaceflight missions will face the complex challenge of performing human extravehicular activity (EVA) beyond the low Earth orbit (LEO) environment. Astronauts will become increasingly isolated from Earth-based mission support and thus will rely heavily on their own decision-making capabilities and onboard tools to accomplish proposed EVA mission objectives. To better address time delay...
Increasing the temperature in power electronic applications usually causes a decreasing lifetime and reliability. This study shows that packaging materials and technologies, such as silver-sintering or gold germanium solders combined with silicon-carbide devices, can easily deal with temperatures above 200 °C/392 °F. Furthermore, lifetime tests (active power cycling) with 300 devices offered more...
Orbital robotics is receiving growing attention worldwide for applications in servicing and repositioning of partially or fully defective satellites. In this paper, we present the scope and main results of a four-year research project, which aimed at developing necessary robotic technologies for such applications. The scope is two-fold, since we address both the human-operated robotic operational...
Tethered ball has the characteristics of the long duration, low cost, large payload, high safety performance, and it is widely applied in military and civil fields, especially in the field of various large-scale civilian activities it plays an important role on monitoring tasks. Currently, there is a suspending contradiction between the surveillance range and resolution of the tethered balloon-borne...
An increasingly rapid race for high performance systems has led satellite manufacturers to look for alternatives to traditional radiation hardened microcircuits. One of the approaches is to benefit from existing commercial technology with proven radiation tolerance and focus on specific assembly, test and qualification capabilities to ensure long term reliability once exposed to space environment...
Ultra high speed data converters have applications ranging from data acquisition systems, radar, satellite and terrestrial communications and radio astronomy telescopes. The latest data converters offer signal bandwidths of up to 7GHz along with sample rates at 5GSps and more.
The period between the creation of the cosmic microwave background at a redshift of ∼1000 and the formation of the first stars and black holes that re-ionize the intergalactic medium at redshifts of 10–20 is currently unobservable. The baryonic component of the universe during this period is almost entirely neutral hydrogen, which falls into local regions of higher dark matter density. This seeds...
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