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NASA NTRSDate not supplied

Autonomous Lunar Infrastructure Outfitting

The Automated Reconfigurable Mission Adaptive Digital Assembly Systems (ARMADAS) project at NASA Ames Research Center is developing autonomous infrastructure, instrumentation, and spacecraft assembly and manufacturing capabilities for next generation exploration and science missions, with a goal to change the cost scaling of these missions relative to mission size and duration. Using a building-block approach with a 'kit of parts' composed of ultra-light, high-performance mechanical metamaterials, simplified robots leverage the period environment to achieve high levels of autonomy and reliability for in-space and surface assembly of large-scale apertures, solar-arrays, towers, habitats, and other infrastructure. Robots and structure break down into a compact form factor for launch. By leveraging economies of scale and achieving high-packing ratios, ARMADAS technology can revolutionize space missions by breaking the tyranny of the launch shroud, decreasing development times, decreasing mission costs for transformative science capability, and providing a scalable and versatile space infrastructure strategy. An ecosystem of reconfigurable infrastructure modules can be reused, repaired, expanded reconfigured to meet emergency or unforeseen needs, and reduce spare parts.

Christine Gregg↗
NASA NTRSDate not supplied

Development of a Generic Small-Satellite Payload for On-Orbit Characterization and Evaluation of Novel Radiation-Shielding Materials

There is a need for lightweight and novel radiation shielding for small satellites operating in LEO and beyond. Current state of the art shielding materials include aluminum and polyethylene, or no shielding due to weight and dimensional considerations. New materials are being developed which may offer advantages over current options. These materials include novel lightweight composites impregnated with metallic nanoparticles, chitin-derived bioplastics, and aerogel-family materials. A compact experiment platform that allows the simultaneous testing of a number of potential shielding materials will be useful in comparing and validating them. The effort now underway seeks to develop a miniaturized, modularized payload which will allow testing of materials using 1U CubeSat form factor modules with four scintillator radiation detectors arrayed behind four sample material windows exposed to space. The first proposed mission will utilize a 2U payload volume to host two test quartets enabling eight materials to be tested. Such a test platform can potentially be used as a hosted payload on a variety of spacecraft to test other materials in the future.

Avery D Brock↗
NASA NTRSDate not supplied

Designing Experiments for SpinSat, A Novel Variable-Gravity-and-Radiation Platform for Deep-Space Science

Conducting experiments to measure the effects of deep-space radiation and reduced gravity on biological and physical systems remains challenging. The result is a substantial knowledge gap that poses risks to our ability to sustain life and conduct critical operations in deep space. The SpinSat spacecraft platform is designed to bridge such gaps by providing low-cost, reliable, and frequent access to deep space. A disk-shaped rotating satellite that can provide artificial gravity and exposure to space radiation simultaneously, SpinSat is designed to accommodate payloads in a CubeSat form factor (with at least 48 “U” volume), providing power, communications, and a benign thermal environment. It is orbit-agnostic, enabling access to a variety of radiation environments (Van Allen belts, deep space, cis-lunar); and can be equipped with shielding to mimic planetary radiation environments, for both short- and long-term experiments. Because of its versatility and prioritization of late loading for biological payloads, it is well suited to host a wide range of ranging from human tissues and organoids to microorganisms, plants, chemistry, and regolith. Here, we present examples of potential experiment concepts for SpinSat, and discuss the details of how experimental designs could interact with the platform. Potential SpinSat studies have diverse applications, including fundamental radiation biology and DNA repair; cancer biology and countermeasure development; space agriculture; bioproduction of nutrients and pharmaceuticals; understanding regolith dynamics in low gravity; prebiotic chemistry and panspermia. We will further highlight ideas for SpinSat-compatible experimental hardware, existing and in development, and experiment-relevant details on SpinSat capabilities including artificial gravity, potential radiation environments, data, and power. This presentation will aim to provide investigators with the high-level technical information necessary to inspire experiments for SpinSat. We also seek to stimulate conversation and to gain community input on accommodations needs to help guide the evolving design of this platform.

experiment design↗
NASA NTRSDate not supplied

A Vacuum-Compatible, Spectrally Tunable, Flat Panel Uniform Source for Testing Large Aperture Earth Observation Systems

Labsphere, Inc. in conjunction with NASA GSFC and Genesis Engineering Solutions Inc., has developed an innovative, vacuum compatible, calibration spectro-radiometric illumination source with a highly uniform large-area rectangular flat panel active area. This device features a uniquely shaped diffuse integration geometry to achieve high uniformity over a large active output area while maintaining a smaller and more robust overall form-factor when compared to previous designs or integrating spheres. A new liquid-cooled hybrid quartz-tungsten (QT) and light emitting diode (LED) source module has been engineered to provide direct-in-vacuum reference illumination over the full dynamic range and spectrum of the VIIRS instrument’s optical bands during pre-launch testing. The first unit has been demonstrated to meet its requirements using ambient technology and a fully-vacuum-compatible second unit is planned to allow testing in thermal vacuum (TVAC) campaigns. This technology is flexible and capable of meeting the needs of many other instruments/missions requiring this type of test/calibration capability.

Jeffrey Holt↗
NASA NTRSDate not supplied

Overview of the NASA LISA Laser System Development

NASA Goddard Space Flight Center (GSFC) is developing the Laser System (LS) for the Laser Interferometer Space Antenna (LISA) mission, led by the European Space Agency (ESA) with a launch date of 2035. The LS under development at NASA GSFC consists of the Laser Head (LH), the Frequency Reference System (FRS), and the Power Monitor (PMON) Detector Assemblies. Since late 2017, we have been developing various models to advance the technology readiness level (TRL) for the LH from prototype (TRL4) to a system model demonstration in a relevant environment (TRL6). For the LH and FRS, the models further breakdown into the optical and electronics modules where the LH is made up of the Laser Optical Module (LOM) and the Laser Electronics Module (LEM) and the FRS consists of the FRS Optical Reference Cavity (FRS-O) and the FRS Electronics (FRS-E). The LS development follows the established NASA process in demonstrating the performance requirements [1] through the TRL4 effort and then advancing the form factor and package design to meet relevant environment requirements and qualifying the TRL6 design through rigorous testing and performance verification for space applications. The LOM for the LH is a main oscillator power amplifier (MOPA) with wavelength of 1064 nm and nominal output power of 2 Watt throughout the mission. The low-power, low-noise main oscillator (MO) is a custom micro non-planar ring oscillator (µNPRO) [2] that is phase modulated then amplified by the forward pumped ytterbium-dope fiber power amplifier (PA) stage to meet the output power requirement. The FRS is baselined on the GRACE Follow-On (GFO) [3] approach with updated FRS-E design to work with the LH-LEM. The PMON is located on the Optical Bench Assembly (OBA) [4] that samples a small portion of the LH output signal and provides the feedback signal to the LH-LEM for relative intensity noise (RIN) control. In this paper, we will report on the latest status of the LH testing and system level tests, explain the other subsystems involved in the test campaigns, and discuss the path to bring each LS subsystem to TRL6. We will also present the NASA GSFC roadmap in advancing the LISA LS to TRL6+ and plans for future system level testing as well as the preparation for space flight development to meet the LISA launch date of 2035.

amplifier↗
NASA NTRSDate not supplied

Development of a Universal Small-Satellite Payload for On-Orbit Characterization and Evaluation of Novel Radiation-Shielding Materials

There is a need for novel lightweight radiation shielding materials for small satellites operating in LEO and beyond. Current commonly used shielding materials include aluminum and polyethylene, though often no additional shielding than that provided by structure is used due to mass and dimensional constraints. New materials are being developed which may offer advantages over these current solutions. These materials include novel lightweight composites impregnated with metallic nanoparticles, chitin-derived bioplastics, and aerogel-family materials. A compact CubeSat experiment payload that allows the simultaneous testing of numerus potential shielding materials would be useful to enable material comparison and efficacy validation. An effort currently underway seeks to develop such a miniaturized modularized payload, which will enable the testing of materials in 1U CubeSat form factor modules, with each module hosting four scintillator radiation detectors arrayed behind four sample material windows exposed to space. The first proposed mission will utilize a 2U payload volume to host two test quartets enabling eight materials to be tested. Such a test platform can potentially be used as a hosted payload on a variety of spacecraft to test additional materials in the future

Luke Idziak↗
NASA NTRS1990

Similarity of urinary risk factors among stone-forming patients in five regions of the United States

Study Objective: To compare urinary biochemical risk factors among stone-forming patients in the Southeast (SE) or "stone belt" versus four other regions of the United States. Design: Prospective biochemical survey for regional comparisons. Setting: Referral-based nephrolithiasis clinics, urologists, nephrologists, and family practitioners. Patients: Consecutive sample of 3473 stone-forming patients who submitted 24-hour urine collections for biochemical analyses of stone-forming risk factors. Interventions: None. Subjects taking medication known to interfere with stone-forming risk factors were deleted from the final data compilation. Measurements and Main Results: Overall, the mean values for each urinary parameter spanned a narrow range without significant difference between the five regions. Among "metabolic" factors, 40% in the SE had hypercalciuria (> 6.25 mmol/d), compared to 35%-43% in other regions, and hyperuricosuria (> 4.2 mmol/d) was found in 16% in the SE versus 17%-19% elsewhere. Among "environmental" factors, low urine volume ( < 2 L/d) was found in 77% patients in the SE compared to 69%-78% elsewhere, and high sodium was encountered in 27% in the SE versus 24%-29% elsewhere. No differences were noted in occurrence of other abnormal risk factors: hyperoxaluria, hypocitraturia, low pH, high sulfate, high phosphorus, or low magnesium. Conclusions: Despite expected regional differences in nutritional and environmental influences, the results of this study showed a striking similarity in urinary biochemical risk factor profiles of stone-formers in all five regions of the United States.

NASA Discipline Number 18-10↗
NASA NTRS2012

Crystallographic Stability of Metastable Phase Formed by Containerless Processing in REFeO3 (RE: Rare-Earth Element)

Undercooling a melt often facilitates a metastable phase to nucleate preferentially. Although the classical nucleation theory shows that the most critical factor for forming a metastable phase is the interface free energy, the crystallographic stability is also indispensable for the phase to be frozen at ambient temperature. In compound materials such as oxides, authors have suggested that the decisive factors for forming a critical nucleus are not only the free energy difference but also the difference of the entropy of fusion between stable and metastable phases. In the present study, using REFeO3 (RE: rare-earth element) as a model material, we investigate the formation of a metastable phase from undercooled melts with respect to the competitive nucleation and crystallographical stabilities of both phases.

Kuribayashi, Kazuhiko↗
NASA NTRS1996

Uncertainty Modeling for Structural Control Analysis and Synthesis

The development of an accurate model of uncertainties for the control of structures that undergo a change in operational environment, based solely on modeling and experimentation in the original environment is studied. The application used throughout this work is the development of an on-orbit uncertainty model based on ground modeling and experimentation. A ground based uncertainty model consisting of mean errors and bounds on critical structural parameters is developed. The uncertainty model is created using multiple data sets to observe all relevant uncertainties in the system. The Discrete Extended Kalman Filter is used as an identification/parameter estimation method for each data set, in addition to providing a covariance matrix which aids in the development of the uncertainty model. Once ground based modal uncertainties have been developed, they are localized to specific degrees of freedom in the form of mass and stiffness uncertainties. Two techniques are presented: a matrix method which develops the mass and stiffness uncertainties in a mathematical manner; and a sensitivity method which assumes a form for the mass and stiffness uncertainties in macroelements and scaling factors. This form allows the derivation of mass and stiffness uncertainties in a more physical manner. The mass and stiffness uncertainties of the ground based system are then mapped onto the on-orbit system, and projected to create an analogous on-orbit uncertainty model in the form of mean errors and bounds on critical parameters. The Middeck Active Control Experiment is introduced as experimental verification for the localization and projection methods developed. In addition, closed loop results from on-orbit operations of the experiment verify the use of the uncertainty model for control analysis and synthesis in space.

Campbell, Mark E.↗
NASA NTRS1976

Proton-tissue dose buildup factors

When an object is exposed to external radiation, the dose field within the object is a complicated function of the character of the external radiation, the shape of the object (including orientation), and the object's material composition. In this note, the dose conversion factors for protons in tissue are represented using buildup factors. A parametric form for the buildup factors is obtained. The values of the parameters are derived from Monte Carlo calculations of various authors. All the necessary information to estimate nuclear reaction effects in proton irration of convex objects of arbitrary shape is included.

Wilson, J. W.↗
NASA NTRS2008

Probabilistic Multi-Factor Interaction Model for Complex Material Behavior

The Multi-Factor Interaction Model (MFIM) is used to evaluate the divot weight (foam weight ejected) from the launch external tanks. The multi-factor has sufficient degrees of freedom to evaluate a large number of factors that may contribute to the divot ejection. It also accommodates all interactions by its product form. Each factor has an exponent that satisfies only two points, the initial and final points. The exponent describes a monotonic path from the initial condition to the final. The exponent values are selected so that the described path makes sense in the absence of experimental data. In the present investigation the data used was obtained by testing simulated specimens in launching conditions. Results show that the MFIM is an effective method of describing the divot weight ejected under the conditions investigated.

Chamis, Christos C.↗
NASA NTRS2008

Probabilistic Multi-Factor Interaction Model for Complex Material Behavior

The Multi-Factor Interaction Model (MFIM) is used to evaluate the divot weight (foam weight ejected) from the launch external tanks. The multi-factor has sufficient degrees of freedom to evaluate a large number of factors that may contribute to the divot ejection. It also accommodates all interactions by its product form. Each factor has an exponent that satisfies only two points the initial and final points. The exponent describes a monotonic path from the initial condition to the final. The exponent values are selected so that the described path makes sense in the absence of experimental data. In the present investigation, the data used was obtained by testing simulated specimens in launching conditions. Results show that the MFIM is an effective method of describing the divot weight ejected under the conditions investigated.

Chamis, Christos C.↗
NASA NTRS2009

Probabilistic Multi-Factor Interaction Model for Evaluating Continuous Smooth Curves

The Multi-Factor Interaction Model (MFIM) is used to evaluate the divot weight (foam weight ejected) from launch external tanks. The MFIM has sufficient degrees of freedom to evaluate a large number of factors that may contribute to the divot ejection. It also accommodates all interactions by its product form. Each factor has an exponent that satisfies only two points the initial and final points. They are selected so that the MFIM will generate a common curve to fit the individual point data. The results show that the approach used generates the continuous curve.

Chamis, Christos C.↗
NASA NTRS2010

A Unique Computational Algorithm to Simulate Probabilistic Multi-Factor Interaction Model Complex Material Point Behavior

The Multi-Factor Interaction Model (MFIM) is used to evaluate the divot weight (foam weight ejected) from the launch external tanks. The multi-factor has sufficient degrees of freedom to evaluate a large number of factors that may contribute to the divot ejection. It also accommodates all interactions by its product form. Each factor has an exponent that satisfies only two points--the initial and final points. The exponent describes a monotonic path from the initial condition to the final. The exponent values are selected so that the described path makes sense in the absence of experimental data. In the present investigation, the data used was obtained by testing simulated specimens in launching conditions. Results show that the MFIM is an effective method of describing the divot weight ejected under the conditions investigated.

Chamis, Christos C.↗
NASA NTRS1997

Renal stone risk assessment during Space Shuttle flights

PURPOSE: The metabolic and environmental factors influencing renal stone formation before, during, and after Space Shuttle flights were assessed. We established the contributing roles of dietary factors in relationship to the urinary risk factors associated with renal stone formation. MATERIALS AND METHODS: 24-hr. urine samples were collected prior to, during space flight, and following landing. Urinary and dietary factors associated with renal stone formation were analyzed and the relative urinary supersaturation of calcium oxalate, calcium phosphate (brushite), sodium urate, struvite and uric acid were calculated. RESULTS: Urinary composition changed during flight to favor the crystallization of calcium-forming salts. Factors that contributed to increased potential for stone formation during space flight were significant reductions in urinary pH and increases in urinary calcium. Urinary output and citrate, a potent inhibitor of calcium-containing stones, were slightly reduced during space flight. Dietary intakes were significantly reduced for a number of variables, including fluid, energy, protein, potassium, phosphorus and magnesium. CONCLUSIONS: This is the first in-flight characterization of the renal stone forming potential in astronauts. With the examination of urinary components and nutritional factors, it was possible to determine the factors that contributed to increased risk or protected from risk. In spite of the protective components, the negative contributions to renal stone risk predominated and resulted in a urinary environment that favored the supersaturation of stone-forming salts. Dietary and pharmacologic therapies need to be assessed to minimize the potential for renal stone formation in astronauts during/after space flight.

STS Shuttle Project↗
NASA NTRS1996

Renal-Stone Risk Assessment During Space Shuttle Flights

The metabolic and environmental factors influencing renal stone formation before, during, and after Space Shuttle flights were assessed. We established the contributing roles of dietary factors in relationship to the urinary risk factors associated with renal stone formation. 24-hr urine samples were collected prior to, during space flight, and following landing. Urinary factors associated with renal stone formation were analyzed and the relative urinary supersaturation ratios of calcium oxalate, calcium phosphate (brushite), sodium urate, struvite and uric acid were calculated. Food and fluid consumption was recorded for a 48-hr period ending with the urine collection. Urinary composition changed during flight to favor the crystallization of stone-forming salts. Factors that contributed to increased potential for stone formation during space flight were significant reductions in urinary pH and increases in urinary calcium. Urinary output and citrate, a potent inhibitor of calcium-containing stones, were slightly reduced during space flight. Dietary intakes were significantly reduced for a number of variables, including fluid, energy, protein, potassium, phosphorus and magnesium. This is the first in-flight characterization of the renal stone forming potential in astronauts. With the examination of urinary components and nutritional factors, it was possible to determine the factors that contributed to increased risk or protected from risk. In spite of the protective components, the negative contributions to renal stone risk predominated and resulted in a urinary environment that favored the supersaturation of stone-forming salts. The importance of the hypercalciuria was noted since renal excretion was high relative to the intake.

Whitson, Peggy A.↗