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.
Research Containing: Technology demonstration
Reentry Breakup Recorder: An innovative device for collecting data during breakup of reentering objects
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.
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.
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.
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.
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.
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.
The Erasmus Recording Binocular (ERB1) was the first fully digital stereo camera used on the International Space Station. One year after its first utilisation, the results and feedback collected with various audiences have convinced us to continue exploiting the outreach potential of such media, with its unique capability to bring space down to earth, to share the feeling of weightlessness and confinement with the viewers on earth. The production of stereo is progressing quickly but it still poses problems for the distribution of the media. The Erasmus Centre of the European Space Agency has experienced how difficult it is to master the full production and distribution chain of a stereo system. Efforts are also on the way to standardize the satellite broadcasting part of the distribution. A new stereo camera is being built, ERB2, to be launched to the International Space Station (ISS) in September 2008: it shall have 720p resolution, it shall be able to transmit its images to the ground in real-time allowing the production of live programs and it could possibly be used also outside the ISS, in support of Extra Vehicular Activities of the astronauts. These new features are quite challenging to achieve in the reduced power and mass budget available to space projects and we hope to inspire more designers to come up with ingenious ideas to built cameras capable to operate in the hash Low Earth Orbit environment: radiations, temperature, power consumption and thermal design are the challenges to be met. The intent of this paper is to share with the readers the experience collected so far in all aspects of the 3D video production chain and to increase awareness on the unique content that we are collecting: nice stereo images from space can be used by all actors in the stereo arena to gain consensus on this powerful media. With respect to last year we shall present the progress made in the following areas: a) the satellite broadcasting live of stereo content to D-Cinema's in Europe; b) the design challenges to fly the camera outside the ISS as opposed to ERB1 that was only meant to be used in the pressurized environment of the ISS; c) on-board stereo viewing on a stereo camera has been tackled in ERB1: trade offs between OLED and LCOS display technologies shall be presented; d) HD_SDI cameras versus USB2 or Firewire; e) the hardware compression ASIC solutions used to tackle the high data rate on-board; f) 3D geometry reconstruction: first attempts in reconstructing a computer model of the interior of the ISS starting form the stereo video available.
Progressive development of microsatellite technologies has resulted in increased demand for lightweight electrical power subsystems including solar arrays. The use of thin film photovoltaics has been recognized as a key solution to meet the power needs. The lightweight cells can generate sufficient power and still meet critical mass requirements. Commercially available solar cells produced on lightweight substrates are being studied as an option to fulfill the power needs. The commercially available solar cells are relatively inexpensive and have a high payoff potential. Commercially available thin film solar cells are primarily being produced for terrestrial applications. The need to convert the solar cell from a terrestrial to a space compatible application is the primary challenge. Solar cell contacts, grids and interconnects need to be designed to be atomic oxygen resistant and withstand rapid thermal cycling environments. A mechanically robust solar cell interconnect is also required in order to withstand handling during fabrication and survive during launch. The need to produce the solar cell interconnects has been identified as a primary goal of the PowerSphere program and is the topic of this paper. Details of the trade study leading to the final design involving the solar cell wrap around contact, flex blanket, welding process, and frame will be presented at the conference.
The MIT Space Systems Laboratory has developed the Synchronized Position Hold Engage and Reorient Experimental Satellites (SPHERES) facility for the testing of formation flight and autonomous docking algorithms inside the International Space Station (ISS), in NASA's reduced gravity aircraft and in a 1-g laboratory environment. To provide SPHERES with reliable and accurate position, velocity, attitude and angular rate estimation, an innovative state estimation system based on ultrasound transmission has been developed. An extended Kalman filter (EKF) processes time-of-flight data collectedby ultrasonic receivers, as well as angular rate measurements provided by gyroscopes, to compute the state estimates required by the satellites when maneuvering. To increase the robustness of the system, the EKF has been augmented with a fault detection capability that uses the filter innovation (residual) to diagnose measurement errors. Two versions of the algorithm were successfully implemented and used on the SPHERES facility onboard the ISS during a series of five test sessions, from May 2006 to November 2006. This paper describes both versions in detail, along with di culties encountered during the implementation on the hardware and their solution. Results from experiments performed in the ISS to validate the algorithms are also presented.