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Research Containing: Technology demonstration

SPHERES Reconfigurable Control Allocation for Autonomous Assembly

by on 9 June 2015in Technology Development & Demonstration No comment

Current research on control allocation emphasizes reconfiguration for adapting to thruster failures. However, in the application of autonomous assembly, the reconfiguration is necessitated by changing physical properties. For the scenario of an assembler tug constructing a large space structure, every docking and undocking maneuver used for the tug to move an individual payload causes a large shift in the dynamics of the tug. Not only do the mass properties change, but so does the thruster configuration. Changes in the center of mass, mass, and inertia of the tug-payload system, causes changes in the equivalent force exerted by each thruster. This paper explores reconfigurable control allocation to adapt to changes in the mass properties. Specifically considered are changes to the center of mass and thruster configuration (number, location, and active thrusters). Results are presented from the implementation of a reconfigurable control allocation algorithm on the SPHERES (Synchronized Position Hold Engage Reorient Experimental Satellites) testbed aboard the International Space Station. Results demonstrate controllability for configurations with large center of mass shifts, varying number of thrusters, as well as maintaining performance from the baseline non-reconfigurable control allocation algorithm on SPHERES.

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http://dx.doi.org/10.2514/6.2008-7468

Advanced ISS Air Monitoring — The ANITA and ANITA2 Missions

by on 9 June 2015in Technology Development & Demonstration No comment

After 11 months of successful operation onboard the ISS US laboratory Destiny, the air quality monitors ANITA (Analyzing Interferometer for Ambient Air) was brought back to Earth on STS126 (ULF2). ANITA is a technology demonstrator flight experiment for continuous air quality monitoring inside the crewed cabin of the ISS with low detection limits and high time resolution. For the first time, the dynamics of the detected trace gas concentrations could be directly resolved by ANITA and correlated to gas events in the cabin. The system is the result of a long term ESA technology development programme initiated more than seventeen years ago. The ANITA mission was a cooperative project between ESA and NASA. ESA's responsibilities were the provision of the H/W, the data acquisition and the data evaluation. NASA was responsible for the launch, accommodation and operation onboard ISS, data download and the transportation of ANITA back to the Earth. ANITA was calibrated to detect and quantify 30 trace gases simultaneously with down to sub-ppm (parts per million) detection limits in addition to the always present background gases carbon dioxide and water vapour. The results of the mission are summarised in [ 1 ]. Further, with a specially developed gas bag hand pump system also gas analyses were performed on air samples from Node 1 of the Space Station. ANITA is a precursor for a permanent continuous trace gas monitoring system ANITA2 for ISS and future space vehicles. At the time of the conference the follow-on study on ANITA2 will have been initiated. This paper describes the measurement system, the lessons learned during the mission on ISS, and the planned follow-on activities. The work described has been performed under contract of the European Space Agency.

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ANITA Air Monitoring on the International Space Station Part 1: The Mission

by on 9 June 2015in Technology Development & Demonstration No comment

After the launch to the International Space Station with The Space Shuttle flight STS 118 13A.1 on August 9th 2007 and the accommodation in the US lab Destiny, the air quality monitor ANITA (Analyzing Interferometer for Ambient Air) has been successfully put into operation. ANITA is a technology demonstrator flight experiment being able to continuously monitor with high time resolution the air conditions within the crewed cabins of the ISS (International Space Station). The system has its origin in a long term ESA (European Space Agency) technology development program. The ANITA mission itself is an ESA-NASA cooperative project. ESA is responsible for the provision of the HW (Hardware), the data acquisition and data evaluation. NASA's responsibilities are launch, accommodation in the US Lab Destiny, operation and data download. The ANITA air analyser is designed to detect and quantify online and with high time resolution 30 trace gases simultaneously with down to sub-ppm (parts per million) detection limits in addition to the always present background gases carbon dioxide and water vapour. The air analyser thus monitors the trace gas dynamics of the spacecraft's atmosphere in providing continuous air monitoring as well as crew warning capability in case of malfunctions. Beside continuous measurements in the vicinity of the gas monitor, air samples from remote places in the International Space Station can be analyzed using gas bags and a hand pump. However, considering the experimental character of ANITA, the measurements are not on-line visible to the Crew. ANITA is an on-orbit test experiment and a precursor for a permanent continuous trace gas monitoring system on the ISS – ANITA II. It further represents a precursor system for future air monitoring in crewed vehicles being developed for the Human Space Exploration program. This is the first paper of two describing the measurement principle, the HW and the mission on the ISS. Finally, an outlook into the future highlights the potential of the ANITA technology for the Exploration program. The work described has been performed under contract of the European Space Agency.

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Mold species in dust from the International Space Station identified and quantified by mold-specific quantitative PCR

by on 9 June 2015in Technology Development & Demonstration No comment

Dust was collected over a period of several weeks in 2007 from HEPA filters in the U.S. Laboratory Module of the International Space Station (ISS). The dust was returned on the Space Shuttle Atlantis, mixed, sieved and the DNA was extracted. Using a DNA-based method called mold-specific quantitative PCR (MSQPCR), 39 molds were measured in the dust. Potential opportunistic pathogens Aspergillus flavus and Aspergillus niger and potential moderate toxin producers Penicillium chrysogenum and Penicillium brevicompactum were noteworthy. No cells of the potential opportunistic pathogens Aspergillus fumigatus, Aspergillus terreus, Fusarium solani or Candida albicans were detected.

Related URLs:
http://www.sciencedirect.com/science/article/pii/S0923250808000892

Reentry Breakup Recorder: An innovative device for collecting data during breakup of reentering objects

by on 9 June 2015in Technology Development & Demonstration No comment

More than 40 large, human-made, uncontrolled objects reenter the earth's atmosphere every year, and some fraction of the mass of each object survives to impact the ground or water. Some of these surviving objects are sizable and potentially hazardous. Recognizing this fact, space agencies are developing regulations and standards to limit ground hazards. Unfortunately, detailed information on how objects respond to the severe heating and loads environment is not available due to the difficulty in recording and broadcasting data during reentry and breakup. The Reentry Breakup Recorder (REBR) was developed using a different paradigm – rather than broadcasting data during the breakup event, record the data and broadcast it after the reentry has effectively ended, but before the data recorder actually impacts the Earth's surface. The paper describes how this approach minimizes the weight of the recording device and the overall cost of data recovery. The first flight tests of the REBR device were conducted in 2011; a REBR was inside the Japanese HTV2 and the European ATV-2 vehicles when they were deorbited into the Pacific Ocean. The paper presents a summary of the results of those tests and gives an overview of how future versions of REBR will revolutionize our understanding of reentry breakup and might be used to prototype "black box" systems for space transportation vehicles.

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Swing bed canister with heat transfer features

by on 9 June 2015in Technology Development & Demonstration No comment

A swing bed canister assembly for a regenerative carbon dioxide removal system includes a housing that includes an integrally formed central wall that divides an adsorbing amine bed from a desorbing amine bed. The central wall defines spaces for each of the amine beds so that each portion of the desorbing amine bed is disposed in thermal communication with an adsorbing amine bed to facilitate desorption.

Related URLs:
https://www.google.com/patents/US7637988

International space station: A testbed for experimental and computational dosimetry

by on 9 June 2015in Technology Development & Demonstration No comment

The ISS and the prior station Mir provided the proving ground for future human long-duration space activity. A recent European Space Agency study recommended “Measurement campaigns on the ISS form the ideal tool for experimental validation of radiation environment models, of transport code algorithms and reaction cross sections”. Indeed, prior measurements on Shuttle have provided vital information impacting both transport code and environmental model development. Recent studies using the ISS 7A configuration with TLD area monitors demonstrated that computational dosimetry requires environmental models with accurate anisotropic and dynamic behavior, detailed information on rack loading, and an accurate 6 degree-of-freedom description of the ISS trajectory. The ISS model is now configured for 11A and uses an anisotropic and dynamic geomagnetic transmission and trapped proton models. The ISS 11A is instrumented with both passive and active dosimetric devices. Time resolved measurements have the advantage of isolating trapped proton and galactic cosmic ray components as was essential to transport code validation in Shuttle data analysis. ISS 11A model validation will begin with passive dosimetry as was used with ISS 7A. Directional dependent active measurements will play an important role in the validation of environmental model anisotropies.

Related URLs:
http://www.sciencedirect.com/science/article/pii/S0273117705001742

Time serial analysis of the induced LEO environment within the ISS 6A

by on 9 June 2015in Technology Development & Demonstration No comment

Anisotropies in the low Earth orbit (LEO) radiation environment were found to influence the thermoluminescence detectors (TLD) dose within the (International Space Station) ISS 7A Service Module. Subsequently, anisotropic environmental models with improved dynamic time extrapolation have been developed including westward and northern drifts using AP8 Min & Max as estimates of the historic spatial distribution of trapped protons in the 1965 and 1970 era, respectively. In addition, a directional dependent geomagnetic cutoff model was derived for geomagnetic field configurations from the 1945 to 2020 time frame. A dynamic neutron albedo model based on our atmospheric radiation studies has likewise been required to explain LEO neutron measurements. The simultaneous measurements of dose and dose rate using four Liulin instruments at various locations in the US LAB and Node 1 has experimentally demonstrated anisotropic effects in ISS 6A and are used herein to evaluate the adequacy of these revised environmental models.

Related URLs:
http://www.sciencedirect.com/science/article/pii/S0273117706007885

Assessment and control of spcaecraft charging risks on the International Space Station

by on 9 June 2015in Technology Development & Demonstration No comment

The International Space Station (ISS) operates in the F2 region of Earth's ionosphere, orbiting at altitudes ranging from 350 to 450 km at an inclination of 51.6 degrees. The relatively dense, cool F2 ionospheric plasma suppresses surface charging processes much of the time, and the flux of relativistic electrons is low enough to preclude deep dielectric charging processes. The most important spacecraft charging processes in the ISS orbital environment are: 1) ISS electrical power system interactions with the F2 plasma, 2) magnetic induction processes resulting from flight through the geomagnetic field and, 3) charging processes that result from interaction with auroral electrons at high latitude. Recently, the continuing review and evaluation of putative ISS charging hazards required by the ISS Program Office revealed that ISS charging could produce an electrical shock hazard to the ISS crew during extravehicular activity (EVA). ISS charging risks are being evaluated in an ongoing measurement and analysis campaign. The results of ISS charging measurements are combined with a recently developed model of ISS charging (the Plasma Interaction Model) and an exhaustive analysis of historical ionospheric variability data (ISS Ionospheric Specification) to evaluate ISS charging risks using Probabilistic Risk Assessment (PRA) methods. The PRA combines estimates of the frequency of occurrence and severity of the charging hazards with estimates of the reliability of various hazard controls systems, as required by NASA s safety and risk management programs, to enable design and selection of a hazard control approach that minimizes overall programmatic and personnel risk. The PRA provides a quantitative methodology for incorporating the results of the ISS charging measurement and analysis campaigns into the necessary hazard reports, EVA procedures, and ISS flight rules required for operating ISS in a safe and productive manner.

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SPHERES Operations aboard the ISS: Maturation of GN&C Algorithms in Microgravity

by on 9 June 2015in Technology Development & Demonstration No comment

The Synchronized Position Hold Engage Reorient Experimental Satellites (SPHERES) Program, at the MIT Space Systems Laboratory, provides research scientists with a facility to incrementally and iteratively mature estimation, control, autonomy, and artificial intelligence algorithms to advance the field of Distributed Satellite Systems. Operations aboard the ISS began in May 2006, with a total of five sessions completed by the end of 2006. These sessions achieved a wide range of successes including the demonstration of both formation flight and autonomous docking algorithms. The docking algorithms were developed incrementally throughout the five tests sessions, making heavy use of the reconfiguration and modularity features of the SPHERES design. The architecture for the docking algorithms is based on the development of smaller simple modules that implement: two estimation algorithms based on extended Kalman filters; mixer functions to convert forces and torques to thruster on/off commands; glideslope, phase-plane, and PID-type controllers; and fault detection and isolation algorithms. The modules were tested piecewise and assembled together to create increasingly complex docking maneuvers. The tests culminated with the successful demonstration of two SPHERES satellites performing cooperative docking to fixed targets, demonstrating the capabilities of safe docking maneuvers, and performing the first microgravity docking to a tumbling target.

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