Extrasolar solar-sail trajectories and dark matter

Hyper-thin, high-speed solar-photon sail space probes exploring the Sun?s Oort comet cloud could also be used to set an upper bound to the concentration of WIMPS (weakly interacting massive particles), one of the suggested (but unconfirmed) forms of dark matter within the vicinity of the solar system. Newton?s Shell Theorem would be applied to determine variations in apparent solar mass as the probe moves further out from the Sun. Application of this technique to the trajectories of Pioneer 10/11 reveals that the upper limit to WIMP concentration within ~60 AU of the Sun is ~0.2 Earth masses, as revealed in studies of the Pioneer Anomaly. If the published accuracy of the Pioneer acceleration measurements can be increased by an order of magnitude, probe trajectory measurements out to ~10,000 AU may confirm or falsify the hypothesis that WIMP mass within the solar vicinity is ~3X star mass. It is shown that a space-manufactured ~40-nm thick beryllium hollow-body solar sail deployed from a ~0.07 AU perihelion is a candidate spacecraft for such a mission. Possible science-team organization strategy for a ~100-year mission to ~10,000 AU is discussed.     

A concept for NASA's Mars 2016 astrobiology field laboratory

The Mars Program Plan includes an integrated and coordinated set of future candidate missions and investigations that meet fundamental science objectives of NASA and the Mars Exploration Program (MEP). At the time this paper was written, these possible future missions are planned in a manner consistent with a projected budget profile for the Mars Program in the next decade (2007-2016). As with all future missions, the funding profile depends on a number of factors that include the exact cost of each mission as well as potential changes to the overall NASA budget. In the current version of the Mars Program Plan, the Astrobiology Field Laboratory (AFL) exists as a candidate project to determine whether there were (or are) habitable zones and life, and how the development of these zones may be related to the overall evolution of the planet. The AFL concept is a surface exploration mission equipped with a major in situ laboratory capable of making significant advancements toward the Mars Program's life-related scientific goals and the overarching Vision for Space Exploration. We have developed several concepts for the AFL that fit within known budget and engineering constraints projected for the 2016 and 2018 Mars mission launch opportunities. The AFL mission architecture proposed here assumes maximum heritage from the 2009 Mars Science Laboratory (MSL). Candidate payload elements for this concept were identified from a set of recommendations put forth by the Astrobiology Field Laboratory Science Steering Group (AFL SSG) in 2004, for the express purpose of identifying overall rover mass and power requirements for such a mission. The conceptual payload includes a Precision Sample Handling and Processing System that would replace and augment the functionality and capabilities provided by the Sample Acquisition Sample Processing and Handling system that is currently part of the 2009 MSL platform.     

Oxidant enhancement in martian dust devils and storms: storm electric fields and electron dissociative attachment

Laboratory studies, numerical simulations, and desert field tests indicate that aeolian dust transport can generate atmospheric electricity via contact electrification or "triboelectricity." In convective structures such as dust devils and dust storms, grain stratification leads to macroscopic charge separations and gives rise to an overall electric dipole moment in the aeolian feature, similar in nature to the dipolar electric field generated in terrestrial thunderstorms. Previous numerical simulations indicate that these storm electric fields on Mars can approach the ambient breakdown field strength of approximately 25 kV/m. In terrestrial dust phenomena, potentials ranging from approximately 20 to 160 kV/m have been directly measured. The large electrostatic fields predicted in martian dust devils and storms can energize electrons in the low pressure martian atmosphere to values exceeding the electron dissociative attachment energy of both CO2 and H2O, which results in the formation of the new chemical products CO/O- and OH/H-, respectively. Using a collisional plasma physics model, we present calculations of the CO/O- and OH/H- reaction and production rates. We demonstrate that these rates vary geometrically with the ambient electric field, with substantial production of dissociative products when fields approach the breakdown value of approximately 25 kV/m. The dissociation of H2O into OH/H- provides a key ingredient for the generation of oxidants; thus electrically charged dust may significantly impact the habitability of Mars.     

Microscopic approach to analyze solar-sail space-environment effects

Near-sun space-environment effects on metallic thin films solar sails as well as hollow-body sails with inflation fill gas are considered. Analysis of the interaction of the solar radiation with the solar-sail materials is presented. This analysis evaluates worst-case solar radiation effects during solar-radiation-pressure acceleration. The dependence of the thickness of solar sail on temperature and on wavelength of the electromagnetic spectrum of solar radiation is investigated. Physical processes of the interactions of photons, electrons, protons and α-particles with sail material atoms and nuclei, and inflation fill gas molecules are analyzed. Calculations utilized conservative assumptions with the highest values for the available cross sections for interactions of solar photons, electrons and protons with atoms, nuclei and hydrogen molecules. It is shown that for high-energy photons, electrons and protons the beryllium sail is mostly transparent. Sail material will be partially ionized by solar UV and low-energy solar electrons. For a hollow-body photon sail effects including hydrogen diffusion through the solar-sail walls, and electrostatic pressure is considered. Electrostatic pressure caused by the electrically charged sail’s electric field may require mitigation since sail material tensile strength decreases with elevated temperature. It also can substitute inflation-gas pressure loss due to gas diffusion and perforation by micrometeoroids impact to keep the sail inflated.     

The Ultraviolet Spectrograph on NASA’s Juno Mission

The ultraviolet spectrograph instrument on the Juno mission (Juno-UVS) is a long-slit imaging spectrograph designed to observe and characterize Jupiter’s far-ultraviolet (FUV) auroral emissions. These observations will be coordinated and correlated with those from Juno’s other remote sensing instruments and used to place in situ measurements made by Juno’s particles and fields instruments into a global context, relating the local data with events occurring in more distant regions of Jupiter’s magnetosphere. Juno-UVS is based on a series of imaging FUV spectrographs currently in flight—the two Alice instruments on the Rosetta and New Horizons missions, and the Lyman Alpha Mapping Project on the Lunar Reconnaissance Orbiter mission. However, Juno-UVS has several important modifications, including (1) a scan mirror (for targeting specific auroral features), (2) extensive shielding (for mitigation of electronics and data quality degradation by energetic particles), and (3) a cross delay line microchannel plate detector (for both faster photon counting and improved spatial resolution). This paper describes the science objectives, design, and initial performance of the Juno-UVS.     

Miniaturized laser-induced plasma spectrometry for planetary in situ analysis – The case for Jupiter’s moon Europa

Jupiter’s icy moon Europa is one of most promising places in our Solar System where possible extraterrestrial life forms could exist either in the past or even presently. The Europa Lander mission, an exciting part of the international Europa Jupiter System Mission (EJSM/Laplace), considers in situ planetary exploration of the moon. The distance of Europa from the Earth and the Sun asks for autonomous analytical tools that maximize the scientific return at minimal resources, demanding new experimental concepts. We propose a novel instrument, based on the atomic spectroscopy of laser generated plasmas for the elemental analysis of Europa’s surface materials as far as it is in reach of the lander for example by a robotic arm or a mole, or just onboard the lander. The technique of laser-induced plasma spectrometry provides quantitative elemental analysis of all major and many trace elements. It is a fast technique, i.e. an analysis can be performed in a few seconds, which can be applied to many different types of material such as ice, dust or rocks and it does not require any sample preparation. The sensitivity is in the range of tens of ppm and high lateral resolution, down to 50 μm, is feasible. In addition, it provides the potential of depth profiling, up to 2 mm in rock material and up to a few cm in more transparent icy matrices. Key components of the instrument are presently developed in Germany for planetary in situ missions. This development program is accompanied by an in-depth methodical investigation of this technique under planetary environmental conditions.     

Three Years of Progress in Integrated Diagnostics

In 1983 the NSIA sponsored the first Integrated Diagnostics National Conference. The major finding from this Conference was the lack of integration of those technologies which are part of the diagnostic process. Since that time, much has been done to implement the concept of integrated diagnostics. The NSIA has produced a baseline report on the implementation of the concept. This was followed by a series of Service programs aimed at implementation. The Office of the Secretary of Defense considers solutions to the diagnostic problem to be one of its major R&D goals. This paper discusses the progress made during the last three years on the implementation of integrated diagnostics. The paper also discusses the author's ideas on where the program is going.     

Progress in multilateral Earth observation cooperation: CEOS, IGOS and the ad hoc Group on Earth Observations

The Committee on Earth Observation Satellites (CEOS) coordinates international civil space-borne missions designed to observe and study planet Earth. With over 100 Earth observation satellites expected to be launched during the next 10 years, it is clear that collaborative opportunities have not been fully maximized. In 2003 CEOS has been focusing on articulating a more comprehensive satellite data utilization approach and in following up on its significant involvement in the World Summit on Sustainable Development. The CEOS Chair also serves as Co-Chair of the Integrated Global Observing Strategy (IGOS) Partnership, which seeks to reduce observation gaps and unnecessary overlaps and to harmonize and integrate common interests of space-based and in situ systems. IGOS focused in 2003 on development of a number of themes, including Carbon Cycle, Water Cycle and GeoHazards. The IGOS Ocean Theme is now in its implementation phase. NOAA, while chairing CEOS and co-chairing IGOS, has also been actively involved in organizing and hosting a ministerial-level Earth Observation Summit with a follow-on Group on Earth Observations (GEO) charged with developing the framework for a comprehensive global Earth observation system(s). All these activities demonstrate the commitment to developing more coherent and sustained Earth observation strategies for the good of the planet.