Cubesats operating in deep space face challenges Earth-orbiting cubesats do not. 15 deep space cu... more Cubesats operating in deep space face challenges Earth-orbiting cubesats do not. 15 deep space cubesat 'prototypes' will be launched over the next two years including the two MarCO cubesats, the 2018 demonstration of dual communication system at Mars, and the 13 diverse cubesats being deployed from the SLS EM1 mission within the next two years. Three of the EM1 cubesat missions, including the first deep space cubesat 'cluster', will be lunar orbiters with remote sensing instruments for lunar surface/regolith measurements. These include: Lunar Ice Cube, with its 1-4 micron broadband IR spectrometer, BIRCHES, to determine volatile distribution as a function of time of day; Lunar Flashlight, to confirm the presence of surface ice at the lunar poles, utilizing an active source (laser), and looking for absorption features in the returning signal; and LunaH-Map to characterize ice at or below the surface at the poles with a compact neutron spectrometer. In addition, the BIRCHES instrument on Lunar Ice Cube will provide the first demonstration of a microcryocooler (AIM/IRIS) in deep space. Although not originally required to do so, all will be delivering science data to the Planetary Data System, the first formal archiving effort for cubesats. 4 of the 20 recently NASA-sponsored (PSDS3) study groups for deep space cubesat/smallsat mission concepts were lunar mission concepts, most involving 12U cubesats. NASA SIMPLEX 2/SALMON 3 AO will create ongoing opportunities for low-cost missions as 'rides' on government space program or private sector vehicles as these become available.
With the insertion of the NEAR spacecraft into orbit around the asteroid 433 Eros, a new stage of... more With the insertion of the NEAR spacecraft into orbit around the asteroid 433 Eros, a new stage of asteroid exploration has begun, with the return of spatially resolved mineralogical, geological, and chemical information from specific asteroids. In this paper, we outline the features of a partially differentiated asteroid using the acapulcoite and lodranite meteorites as a guide. Such a body would likely contain a variety of lithologies, including chondritic rocks largely unaltered by melting, residues of partial melts, and basaltic and Fe,Ni-FeS rocks crystallized from the partial melts. The presence or nature of the regolith remains largely unconstrained. Mineralogical and isotopic heterogeneities preserved in these rocks suggest spatial separation of these rock types by distances in excess of 200 m. Spacecraft-based remote sensing instrumentation should detect substantial spectral heterogeneity (most prominently manifested in the band area ratio) and chemical heterogeneity. Observation of these various lithologies in situ would provide important new constraints on the processes involved during the earliest differentiation of asteroids.
Nanotechnology, taken to its full three-dimensional potential, will place within the volume of a ... more Nanotechnology, taken to its full three-dimensional potential, will place within the volume of a cube of sugar systems of vast complexity that far exceed the quantitative and qualitative capabilities of today's largest supercomputers. Currently, the uncertainty and imprecision of the real world is tamed, rigidly fixed, by addressable, digital techniques and the careful orchestration of digital patterns within our machines.
ANTS Architecture is based on Addressable Reconfigurable Technology (ART) adaptable for the full ... more ANTS Architecture is based on Addressable Reconfigurable Technology (ART) adaptable for the full spectrum of activities in space. ART systems based on currently available electromechanical (EMS) technology could support human crews on the lunar surface within the next 10 to 15 years. Two or more decades from now, NEMS (Super Miniaturized ART or SMART) technology could perform fully autonomous surveys and operations beyond the reach of human crews. Power system requirements would range from 1 kg to generate tens of Watts for near term ART applications, such as a lunar or Mars Lander Amorphous Rover Antenna (LARA), to <0.1 kg to generate hundreds of mWatts for more advanced SMART applications. POWER SYSTEMS FOR FUTURE MISSIONS Availability of small radioisotope power system (RPS) technology will enable opportunities for scientifically valuable missions which were previously unachievable (Mondt, 2000; Johnson, 2002). Batteries based on this technology will allow modest vehicles to operate in areas of minimal to non-existent insolation over long periods of time, in unilluminated hemispheres of terrestrial planets, or in or on targets beyond the asteroid belt. Such vehicles would include subsatellites and small rovers with reasonable payloads with power requirements in the tens of watts to tens of milliwatts range, equipped with supplemental systems for peak load operations. This power generation technology is particularly applicable to ANTS architecture applications, which are extremely efficient in operation, and thus have modest power and minimal weight requirements (Curtis et al, 2000; Clark et al, 2004a, 2004b, 2004c). THE ANTS CONCEPT The Autonomous NanoTechnology Swarm (ANTS) Architecture is based on Addressable Reconfigurable Technology (ART) adaptable for the full spectrum of activities in remote/hazardous environments such as space. The architecture is based on the tetrahedron as a building block, with edges consisting of struts deployed from nodes at apices. Tetrahedra are combined to form space-filling networks of nodes and struts. ANTS systems based on available electromechanical technology (@ 1kg/m2) could support human crews on the lunar surface within the next 10 to 15 years. A prototype of such a system is currently under construction. ANTS systems based on NEMs (Super Miniaturized ART or SMART) technology (@ >5g/m2) could perform fully autonomous surveys and operations beyond the reach of human crews two or more decades from now. Basic structural components are highly modular, addressable arrays of robust nodes, from which highly reconfigurable struts, acting as supports or tethers, or surfaces, are efficiently reversibly deployed/stowed, transforming the structures as required for all functions in space and on the ground. Reusability of ANTS components thus limits the need for resources, along with cost, mass, size, bandwidth, power, and, of course, expendables. ANTS systems have already been conceptualized for three applications spanning three decades (LARA: Lander Amorphous Rover Antenna; PAM: Prospecting Asteroid Mission; SARA: Saturn Autonomous Ring Array) (Clark et al, 2004b, 2004c, 2004d) where solar illumination could be minimal, including high latitude or polar regions, below ground, or beyond 3 AU. Thus, the use of small radioisotope power systems is particularly appealing.
55th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law
Advances in micro- and nano-fabrication present to us the opportunity to reconsider how the very ... more Advances in micro- and nano-fabrication present to us the opportunity to reconsider how the very mechanical structure of a spacecraft may be implemented. These advances will be at least as important as the development of structural truss technology. A new mechanical architecture called Super Miniaturized Addressable Reconfigurable Technology (SMART) has been developed to guide the integration of sensing, actuation, and
We report a large database of bulk meteorite elemental abundances, compiled to aid in the interpr... more We report a large database of bulk meteorite elemental abundances, compiled to aid in the interpretation of elemental abundance data determined by remote-sensing instrumentation on planetary missions. A custom user interface was developed for easy access and manipulation of the abundance data. The database contains almost-*** individual analyses of more than +*** individual meteorites. Most major and minor elements are included, as well as small number of trace elements measurable by remote-sensing gamma-ray spectroscopy (notably Th and U). All meteorite classes show variability in bulk compositions between individual analyses. Some of this spread is intrinsic to the parent bodies of the meteorites. However, some variability is undoubtedly due to systematic uncertainties, caused by inter-laboratory bias, misclassification, e#ect of weathering, and unrepresentative sampling. We use the database here to investigate both how well di#erent meteorite groups can be distinguished on the basis of bulk compositions and how bulk compositions can be related to the cosmochemical and geological processes that produced them. The major elements measurable by X-ray and gamma-ray remote-sensingῌoxygen, magnesium, aluminum, silicon, sulfur, calcium and ironῌreflect to di#ering degrees nebular elemental fractionations and parent-body igneous processes and can be used together to distinguish most classes and sub-classes of meteorites. Potassium is potentially useful as a tracer of thermal processes in the early solar system. Thorium and uranium abundances could be used to trace igneous processes on di#erentiated asteroids.
Remote sensing Xvray and gamma-ray spectrometers can be usedto infer elemental composition on atr... more Remote sensing Xvray and gamma-ray spectrometers can be usedto infer elemental composition on atrnosphereless bodies. such as asteroids. the Moon. and Mercury. For Discovery class missions a combined geochem ical experiment package has been proposed that can meet the mission science objectives while still remaining within the mass. power. and cost constraints of the mission. Calculations for two asteroid missions (NEAR and MASTER) indicate that surface mapping at up to ten's of kilometer spatial resolution is possible. and that the relation of the astero id composition to that of meteorite classes should be determined relatively early in the mission. Datasets from each of the two experiments provide independent, yet complimentary measures of elemental abundances. Comparisons between results for the same elements can give information on ncar-surface regolith statigraphy and/or differences between local and regional rock types.
Data processing system for the Near-Earth Asteroid Rendezvous (NEAR) x-ray and gamma-ray spectrom... more Data processing system for the Near-Earth Asteroid Rendezvous (NEAR) x-ray and gamma-ray spectrometer (XGRS) ground system. [Proceedings of SPIE 3768, 74 (1999)]. Timothy P. McClanahan, Irina Mikheeva, Jacob I. Trombka ...
Bulletin of the American Astronomical Society, Sep 1, 1998
We have produced maps of iron abundance in bulk and iron-bearing mineral (pyroxene and olivine) s... more We have produced maps of iron abundance in bulk and iron-bearing mineral (pyroxene and olivine) soil components by combining Apollo Gamma-ray (AGR) and Clementine spectral reflectance (CSR) with lunar soil data to produce a more detailed model of crustal iron distribution than the separate datasets would provide. CSR measurements are most directly correlated to pyroxene iron in lunar soils. We subtracted pyroxene-recalibrated CSR data from AGR bulk iron abundance measurements: the residual iron is clearly correlated with olivine abundance in lunar soils. This work has implications for determining iron distribution for 433 Eros, a Class S asteroid, during the upcoming NEAR mission. We have modeled X-ray and Gamma-ray spectral line ratios for the best meteorite class candidates and can clearly distinguish between them, on the basis of abundance ratios. We have considered the equivalent spectral reflectance measurements, from which mineral abundances would be derived, as well, summarized in the qualitative Meteorite Classification matrix below. With these measurements, we should be able to determine Eros' nearest meteorite analogue, and iron abundance in each component. \begin{tabular}{llll} Si/Fe, Mg/Fe for XGRS & Fe Band Depth, Position & Albedo & Meteorite Class Medium, MediumHigh & Medium, shorter & Medium & Ordinary Chondrite, Type H Medium, High & Medium, longer & Medium & Ordinary Chondrite, Type LL High, Medium & Strong, shorter & High & Achondrite-Eucrite High, High & Strong, longer & High & Achondrite-Diogenite Low, Low & Weak & Medium & Stony Iron-Mesosiderite Low, MediumLow & Weak & Medium & Stony Iron-Pallasite
ABSTRACT Scientific results from current work combined with technological developments in instrum... more ABSTRACT Scientific results from current work combined with technological developments in instrumentation and computing are advancing the use of X-ray spectrometry for remote planetary exploration. Remote X-ray spectrometry now plays a key role in the exploration of: 1) the Moon, the intended target of the ESA Smart-1 mission; 2) the large, S-class asteroid Eros, now the target of the NEAR mission; and 3) Mercury, the intended target of the Messenger mission. Missions have also been proposed for other small bodies. At present, primary requirements for remote X-ray spectrometry are: 1) The target has little or no atmosphere. 2) An X-ray source, generally the sun, is monitored onboard. 3) The source generates a sufficient signal/noise. This constraint is much less stringent for the intrinsically low cosmic ray induced background solid state detectors which are now replacing proportional counters. 3) The spacecraft trajectory has readily deducible target viewing geometries. Detailed knowledge of the source, spacecraft, target body, footprint positions and characteristics (e.g., roughness, degree of illumination, shadowing), as well as adequate (and possibly lengthy) signal integration times must be available. This necessitates more careful determination of acceptable trade-offs in spacecraft and instrument pointing capability, tracking frequency, fuel for active pointing, and cost than allowed by exclusively cheaper/ faster/ better approaches. Considerable improvements in data handling have resulted from our recent experience with large data volume and complex viewing geometries, including: 1) high speed interactive graphics capability for near real-time data monitoring; 2) the integration of models for source X-ray production with spatial information and real-time observations; 3) the incorporation of recently released high energy spectral analysis packages with background removal and peak detection assumptions that are flexible enough to be appropriate; and 4) the development of an interactive compositional database (Nittler et al, 2000) for analogous planetary materials which greatly enhances interactive modeling capabilities.
Cubesats operating in deep space face challenges Earth-orbiting cubesats do not. 15 deep space cu... more Cubesats operating in deep space face challenges Earth-orbiting cubesats do not. 15 deep space cubesat 'prototypes' will be launched over the next two years including the two MarCO cubesats, the 2018 demonstration of dual communication system at Mars, and the 13 diverse cubesats being deployed from the SLS EM1 mission within the next two years. Three of the EM1 cubesat missions, including the first deep space cubesat 'cluster', will be lunar orbiters with remote sensing instruments for lunar surface/regolith measurements. These include: Lunar Ice Cube, with its 1-4 micron broadband IR spectrometer, BIRCHES, to determine volatile distribution as a function of time of day; Lunar Flashlight, to confirm the presence of surface ice at the lunar poles, utilizing an active source (laser), and looking for absorption features in the returning signal; and LunaH-Map to characterize ice at or below the surface at the poles with a compact neutron spectrometer. In addition, the BIRCHES instrument on Lunar Ice Cube will provide the first demonstration of a microcryocooler (AIM/IRIS) in deep space. Although not originally required to do so, all will be delivering science data to the Planetary Data System, the first formal archiving effort for cubesats. 4 of the 20 recently NASA-sponsored (PSDS3) study groups for deep space cubesat/smallsat mission concepts were lunar mission concepts, most involving 12U cubesats. NASA SIMPLEX 2/SALMON 3 AO will create ongoing opportunities for low-cost missions as 'rides' on government space program or private sector vehicles as these become available.
With the insertion of the NEAR spacecraft into orbit around the asteroid 433 Eros, a new stage of... more With the insertion of the NEAR spacecraft into orbit around the asteroid 433 Eros, a new stage of asteroid exploration has begun, with the return of spatially resolved mineralogical, geological, and chemical information from specific asteroids. In this paper, we outline the features of a partially differentiated asteroid using the acapulcoite and lodranite meteorites as a guide. Such a body would likely contain a variety of lithologies, including chondritic rocks largely unaltered by melting, residues of partial melts, and basaltic and Fe,Ni-FeS rocks crystallized from the partial melts. The presence or nature of the regolith remains largely unconstrained. Mineralogical and isotopic heterogeneities preserved in these rocks suggest spatial separation of these rock types by distances in excess of 200 m. Spacecraft-based remote sensing instrumentation should detect substantial spectral heterogeneity (most prominently manifested in the band area ratio) and chemical heterogeneity. Observation of these various lithologies in situ would provide important new constraints on the processes involved during the earliest differentiation of asteroids.
Nanotechnology, taken to its full three-dimensional potential, will place within the volume of a ... more Nanotechnology, taken to its full three-dimensional potential, will place within the volume of a cube of sugar systems of vast complexity that far exceed the quantitative and qualitative capabilities of today's largest supercomputers. Currently, the uncertainty and imprecision of the real world is tamed, rigidly fixed, by addressable, digital techniques and the careful orchestration of digital patterns within our machines.
ANTS Architecture is based on Addressable Reconfigurable Technology (ART) adaptable for the full ... more ANTS Architecture is based on Addressable Reconfigurable Technology (ART) adaptable for the full spectrum of activities in space. ART systems based on currently available electromechanical (EMS) technology could support human crews on the lunar surface within the next 10 to 15 years. Two or more decades from now, NEMS (Super Miniaturized ART or SMART) technology could perform fully autonomous surveys and operations beyond the reach of human crews. Power system requirements would range from 1 kg to generate tens of Watts for near term ART applications, such as a lunar or Mars Lander Amorphous Rover Antenna (LARA), to <0.1 kg to generate hundreds of mWatts for more advanced SMART applications. POWER SYSTEMS FOR FUTURE MISSIONS Availability of small radioisotope power system (RPS) technology will enable opportunities for scientifically valuable missions which were previously unachievable (Mondt, 2000; Johnson, 2002). Batteries based on this technology will allow modest vehicles to operate in areas of minimal to non-existent insolation over long periods of time, in unilluminated hemispheres of terrestrial planets, or in or on targets beyond the asteroid belt. Such vehicles would include subsatellites and small rovers with reasonable payloads with power requirements in the tens of watts to tens of milliwatts range, equipped with supplemental systems for peak load operations. This power generation technology is particularly applicable to ANTS architecture applications, which are extremely efficient in operation, and thus have modest power and minimal weight requirements (Curtis et al, 2000; Clark et al, 2004a, 2004b, 2004c). THE ANTS CONCEPT The Autonomous NanoTechnology Swarm (ANTS) Architecture is based on Addressable Reconfigurable Technology (ART) adaptable for the full spectrum of activities in remote/hazardous environments such as space. The architecture is based on the tetrahedron as a building block, with edges consisting of struts deployed from nodes at apices. Tetrahedra are combined to form space-filling networks of nodes and struts. ANTS systems based on available electromechanical technology (@ 1kg/m2) could support human crews on the lunar surface within the next 10 to 15 years. A prototype of such a system is currently under construction. ANTS systems based on NEMs (Super Miniaturized ART or SMART) technology (@ >5g/m2) could perform fully autonomous surveys and operations beyond the reach of human crews two or more decades from now. Basic structural components are highly modular, addressable arrays of robust nodes, from which highly reconfigurable struts, acting as supports or tethers, or surfaces, are efficiently reversibly deployed/stowed, transforming the structures as required for all functions in space and on the ground. Reusability of ANTS components thus limits the need for resources, along with cost, mass, size, bandwidth, power, and, of course, expendables. ANTS systems have already been conceptualized for three applications spanning three decades (LARA: Lander Amorphous Rover Antenna; PAM: Prospecting Asteroid Mission; SARA: Saturn Autonomous Ring Array) (Clark et al, 2004b, 2004c, 2004d) where solar illumination could be minimal, including high latitude or polar regions, below ground, or beyond 3 AU. Thus, the use of small radioisotope power systems is particularly appealing.
55th International Astronautical Congress of the International Astronautical Federation, the International Academy of Astronautics, and the International Institute of Space Law
Advances in micro- and nano-fabrication present to us the opportunity to reconsider how the very ... more Advances in micro- and nano-fabrication present to us the opportunity to reconsider how the very mechanical structure of a spacecraft may be implemented. These advances will be at least as important as the development of structural truss technology. A new mechanical architecture called Super Miniaturized Addressable Reconfigurable Technology (SMART) has been developed to guide the integration of sensing, actuation, and
We report a large database of bulk meteorite elemental abundances, compiled to aid in the interpr... more We report a large database of bulk meteorite elemental abundances, compiled to aid in the interpretation of elemental abundance data determined by remote-sensing instrumentation on planetary missions. A custom user interface was developed for easy access and manipulation of the abundance data. The database contains almost-*** individual analyses of more than +*** individual meteorites. Most major and minor elements are included, as well as small number of trace elements measurable by remote-sensing gamma-ray spectroscopy (notably Th and U). All meteorite classes show variability in bulk compositions between individual analyses. Some of this spread is intrinsic to the parent bodies of the meteorites. However, some variability is undoubtedly due to systematic uncertainties, caused by inter-laboratory bias, misclassification, e#ect of weathering, and unrepresentative sampling. We use the database here to investigate both how well di#erent meteorite groups can be distinguished on the basis of bulk compositions and how bulk compositions can be related to the cosmochemical and geological processes that produced them. The major elements measurable by X-ray and gamma-ray remote-sensingῌoxygen, magnesium, aluminum, silicon, sulfur, calcium and ironῌreflect to di#ering degrees nebular elemental fractionations and parent-body igneous processes and can be used together to distinguish most classes and sub-classes of meteorites. Potassium is potentially useful as a tracer of thermal processes in the early solar system. Thorium and uranium abundances could be used to trace igneous processes on di#erentiated asteroids.
Remote sensing Xvray and gamma-ray spectrometers can be usedto infer elemental composition on atr... more Remote sensing Xvray and gamma-ray spectrometers can be usedto infer elemental composition on atrnosphereless bodies. such as asteroids. the Moon. and Mercury. For Discovery class missions a combined geochem ical experiment package has been proposed that can meet the mission science objectives while still remaining within the mass. power. and cost constraints of the mission. Calculations for two asteroid missions (NEAR and MASTER) indicate that surface mapping at up to ten's of kilometer spatial resolution is possible. and that the relation of the astero id composition to that of meteorite classes should be determined relatively early in the mission. Datasets from each of the two experiments provide independent, yet complimentary measures of elemental abundances. Comparisons between results for the same elements can give information on ncar-surface regolith statigraphy and/or differences between local and regional rock types.
Data processing system for the Near-Earth Asteroid Rendezvous (NEAR) x-ray and gamma-ray spectrom... more Data processing system for the Near-Earth Asteroid Rendezvous (NEAR) x-ray and gamma-ray spectrometer (XGRS) ground system. [Proceedings of SPIE 3768, 74 (1999)]. Timothy P. McClanahan, Irina Mikheeva, Jacob I. Trombka ...
Bulletin of the American Astronomical Society, Sep 1, 1998
We have produced maps of iron abundance in bulk and iron-bearing mineral (pyroxene and olivine) s... more We have produced maps of iron abundance in bulk and iron-bearing mineral (pyroxene and olivine) soil components by combining Apollo Gamma-ray (AGR) and Clementine spectral reflectance (CSR) with lunar soil data to produce a more detailed model of crustal iron distribution than the separate datasets would provide. CSR measurements are most directly correlated to pyroxene iron in lunar soils. We subtracted pyroxene-recalibrated CSR data from AGR bulk iron abundance measurements: the residual iron is clearly correlated with olivine abundance in lunar soils. This work has implications for determining iron distribution for 433 Eros, a Class S asteroid, during the upcoming NEAR mission. We have modeled X-ray and Gamma-ray spectral line ratios for the best meteorite class candidates and can clearly distinguish between them, on the basis of abundance ratios. We have considered the equivalent spectral reflectance measurements, from which mineral abundances would be derived, as well, summarized in the qualitative Meteorite Classification matrix below. With these measurements, we should be able to determine Eros' nearest meteorite analogue, and iron abundance in each component. \begin{tabular}{llll} Si/Fe, Mg/Fe for XGRS & Fe Band Depth, Position & Albedo & Meteorite Class Medium, MediumHigh & Medium, shorter & Medium & Ordinary Chondrite, Type H Medium, High & Medium, longer & Medium & Ordinary Chondrite, Type LL High, Medium & Strong, shorter & High & Achondrite-Eucrite High, High & Strong, longer & High & Achondrite-Diogenite Low, Low & Weak & Medium & Stony Iron-Mesosiderite Low, MediumLow & Weak & Medium & Stony Iron-Pallasite
ABSTRACT Scientific results from current work combined with technological developments in instrum... more ABSTRACT Scientific results from current work combined with technological developments in instrumentation and computing are advancing the use of X-ray spectrometry for remote planetary exploration. Remote X-ray spectrometry now plays a key role in the exploration of: 1) the Moon, the intended target of the ESA Smart-1 mission; 2) the large, S-class asteroid Eros, now the target of the NEAR mission; and 3) Mercury, the intended target of the Messenger mission. Missions have also been proposed for other small bodies. At present, primary requirements for remote X-ray spectrometry are: 1) The target has little or no atmosphere. 2) An X-ray source, generally the sun, is monitored onboard. 3) The source generates a sufficient signal/noise. This constraint is much less stringent for the intrinsically low cosmic ray induced background solid state detectors which are now replacing proportional counters. 3) The spacecraft trajectory has readily deducible target viewing geometries. Detailed knowledge of the source, spacecraft, target body, footprint positions and characteristics (e.g., roughness, degree of illumination, shadowing), as well as adequate (and possibly lengthy) signal integration times must be available. This necessitates more careful determination of acceptable trade-offs in spacecraft and instrument pointing capability, tracking frequency, fuel for active pointing, and cost than allowed by exclusively cheaper/ faster/ better approaches. Considerable improvements in data handling have resulted from our recent experience with large data volume and complex viewing geometries, including: 1) high speed interactive graphics capability for near real-time data monitoring; 2) the integration of models for source X-ray production with spatial information and real-time observations; 3) the incorporation of recently released high energy spectral analysis packages with background removal and peak detection assumptions that are flexible enough to be appropriate; and 4) the development of an interactive compositional database (Nittler et al, 2000) for analogous planetary materials which greatly enhances interactive modeling capabilities.
Uploads
Papers by Pamela Clark