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NASA NTRS2000

Development of Metal Casting Molds By Sol-Gel Technology Using Planetary Resources

Metals extracted from planetary soils will eventually need to be casted and shaped in-situ to produce useful products. In response to this challenge, we propose to develop and demonstrate the manufacturing of a specific product using Lunar and Martian soil simulants, i.e. a mold for the casting of metal and alloy parts, which will be an indispensable tool for the survival of outposts on the Moon and Mars. Drawing from our combined knowledge of sol-gel and metal casting technologies, we set out to demonstrate the extraordinary potential of mesoporous materials such as aerogels to serve as efficient casting molds as well as fulfilling numerous other needs of an autonomous planetary outpost.

Sibille, L.↗

NASA NTRS2000

Integration of Planetary Protection Activities

Research and activities under this grant have focused on a systematic examination and analysis of critical questions likely to impact planetary protection (PP) controls and implementation for Mars sample return missions (MSR). Four areas in the non-scientific and social realms were selected for special attention because of their importance to future mission planning and concern about critical timing or possible economic impacts on MSR mission implementation. These include: (1) questions of legal uncertainty and the decision making process, (2) public perception of risks associated with sample return, (3) risk communication and Education/Public Outreach , and (4) planetary protection implications of alternative mission architectures, for both robotic and human sample return missions. In its entirety, NAG 2-986 has encompassed three categories of activity: (1) research and analysis (Race), (2) subcontracted research (MacGregor/Decision Research), and (3) consulting services.

Race, Margaret S.↗

NASA NTRS2000

Stability Analysis of the Planetary System Orbiting Upsilon Andromedae

We present results of long-term numerical orbital integrations designed to test the stability of the three-planet system orbiting Upsilon Andromedae and short-term integrations to test whether mutual perturbations among the planets can be used to determine planetary masses. Our initial conditions are based on the latest fits to the radial velocity data obtained by the planet-search group at Lick Observatory. The new fits result in significantly more stable systems than did the initially announced planetary parameters. An analytic analysis of the star and the two outer planets shows that this subsystem is Hill stable up to five. Our integrations involving all three planets show that the system is stable for at least 100 Myr for up to four. In our simulations, we still see a secular resonance between the outer two planets and in some cases large oscillations in the eccentricity of the inner planet.

Lissauer, Jack J.↗

NASA NTRS2000

Meteoritics and Planetary Science Supplement

This special supplement of the Meteoritics and Planetary Science Society Journal contains the abstracts of 324 technical presentations, and the presentations of awards during the Annual meeting of the Meteoritical Society. The abstracts review current research on meteors and planetary sciences.

Sears, Derek W. G.↗

NASA NTRS2000

Mesosphere Dynamics with Gravity Wave Forcing: Planetary Waves - 2

We present results from a non-linear, 3D, time dependent numerical spectral model (NSM) which extends from the ground up into the thermosphere and incorporates Hines' Doppler Spread Parameterization for small-scale gravity waves (GW). Our focal point is the mesosphere where wave interactions are playing a dominant role. We discuss planetary waves in the present paper and diurnal and semi-diurnal tides in the companion paper. Without external time dependent energy or momentum sources, planetary waves (PWs) are generated in the model for zonal wavenumbers 1 to 4, which have amplitudes in the mesosphere above 50 km as large as 30 m/s and periods between 2 and 50 days. The waves are generated primarily during solstice conditions, which indicates that the baroclinic instability (associated with the GW driven reversal in the latitudinal temperature gradient) is playing an important role. Results from a numerical experiment show that GWs are also involved directly in generating the PWs. For the zonal wavenumber m = 1, the predominant wave periods in summer are around 4 days and in winter between 6 and 10 days. For m = 2, the periods are in summer and close to 2.5 and 3.5 days respectively For m = 3, 4 the predominant wave periods are in both seasons close to two days. The latter waves have the characteristics of Rossby gravity waves with meridional winds at equatorial latitudes. A common feature of the PWs (m = 1 to 4) generated in summer and winter is that their vertical wavelengths throughout the mesosphere are large which indicates that the waves are not propagating freely but are generated throughout the region. Another common feature is that the PWs propagate preferentially westward in summer and eastward in winter, being launched from the westward and eastward zonal winds that prevail respectively in summer and winter altitudes below 80 km. During spring and fall, for m = 1 and 2 eastward propagating long period PWs are generated that are launched from the smaller eastward zonal winds that prevail in these seasons. PWs generated in the model produce large amplitude modulations of the diurnal tides at altitudes above 80 km and contribute to their seasonal variations.

Mayr, H. G.↗

NASA NTRS2000

Reconnection in Planetary Magnetospheres

Current sheets in planetary magnetospheres that lie between regions of "oppositely-directed" magnetic field are either magnetopause-like, separating plasmas with different properties, or tail-like, separating plasmas of rather similar properties. The magnetopause current sheets generally have a nearly limitless supply of magnetized plasma that can reconnect, possibly setting up steady-state reconnection. In contrast, the plasma on either side of a tail current sheet is stratified so that, as reconnection occurs, the plasma properties, in particular the Alfven velocity, change. If the density drops and the magnetic field increases markedly perpendicular to the sheet, explosive reconnection can occur. Even though steady state reconnection can take place at magnetopause current sheets, the process often appears to be periodic as if a certain low average rate was demanded by the conditions but only a rapid rate was available. Reconnection of sheared fields has been postulated to create magnetic ropes in the solar corona, at the Earth's magnetopause, and in the magnetotail. However, this is not the only way to produce magnetic ropes as the Venus ionosphere shows. The geometry of the reconnecting regions and the plasma conditions both can affect the rate of reconnection. Sorting out the various controlling factors can be assisted through the examination of reconnection in planetary settings. In particular we observe similar small-scale tearing in the magnetopause current layers of the Earth, Saturn. Uranus and Neptune and the magnetodisk current sheet at Jupiter. These sites may be seeds for rapid reconnection if the reconnection site reaches a high Alfven velocity region. In the Jupiter magnetosphere this appears to be achieved with resultant substorm activity. Similar seeds may be present in the Earth's magnetotail with the first one to reach explosive growth dominating the dynamics of the tail.

Russell, C. T.↗

NASA NTRS2001

Laser Altimetry for Earth and Planetary Science

Laser altimeters are presently operating on spacecraft at Mars (MOLA), at the asteroid 433 Eros (NLR), and an earlier system operated at the Moon (Clementine) several years ago. These systems have all advanced our understanding of the evolution of the primary body and several more laser altimeter systems will be launched in the next several years around Earth and other planets to address a wide range of scientific problems. Laser technology for precision altimetry and atmospheric lidar is still in its infancy but the promise of the technology and its demonstrated results already show that laser altimetry/lidar will play an important role in future space observations. To date, lasers have mapped the Moon, Mars, and an asteroid but in a short while they will help measure the planetary librations of Mercury, the tidal distortions of Europa, and tree heights, upper atmosphere winds and the icecaps of planet Earth. Major areas of interest for the immediate future are the development of long-life lasers that can withstand the rigors of long planetary missions in extreme thermal and radiation environments and continue to operate successfully for many years.

Smith, David E.↗

NASA NTRS2000

International Agreement on Planetary Protection

The maintenance of a NASA policy, is consistent with international agreements. The planetary protection policy management in OSS, with Field Center support. The advice from internal and external advisory groups (NRC, NAC/Planetary Protection Task Force). The technology research and standards development in bioload characterization. The technology research and development in bioload reduction/sterilization. This presentation focuses on: forward contamination - research on the potential for Earth life to exist on other bodies, improved strategies for planetary navigation and collision avoidance, and improved procedures for sterile spacecraft assembly, cleaning and/or sterilization; and backward contamination - development of sample transfer and container sealing technologies for Earth return, improvement in sample return landing target assessment and navigation strategy, planning for sample hazard determination requirements and procedures, safety certification, (liaison to NEO Program Office for compositional data on small bodies), facility planning for sample recovery system, quarantine, and long-term curation of 4 returned samples.

Source record↗

NASA NTRS2001

Scattering Properties of Candidate Planetary Regolith Materials

The laboratory investigation of the scattering properties of candidate planetary regolith materials is an important technique for understanding the physical properties of a planetary regolith. Additional information is contained in the original extended abstract.

Nelson, R. M.↗

NASA NTRS1994

Revision to Planetary Protection Policy for Mars Missions

Under existing COSPAR policy adopted in 1984, missions to Mars (landers, probes, and some orbiters) are designated as Category IV missions. As such, the procedures for implementing planetary protection requirements could include trajectory biasing, cleanrooms, bioload reduction, sterilization of hardware, and bioshields, i. e. requirements could be similar to Viking. However, in 1992, a U. S. National Academy of Sciences study recommended that controls on forward contamination of Mars be tied to specific mission objectives. The report recommended that Mars landers with life detection instruments be subject to at least Viking-level sterilization procedures for bioload reduction, while spacecraft (including orbiters) without life detection instruments be subject to at least Viking-level pre sterilization procedures for bioload reduction but need not be sterilized. In light of this, it is proposed that the current policy's Category IV missions and their planetary protection requirements be divided into two subcategories as follows: Category IV A, for missions comprising landers and probes without life detection experiments and some orbiters, which will meet a specified bioburden limit for exposed surfaces; Category IV B, for landers and probes with life detection experiments, which will require complete system sterilization. For Category IV A missions, bioburden specifications will be proposed and implementing procedures discussed. A resolution will be proposed to modify the existing COSPAR policy to reflect these changes. Similar specifications, procedures, and resolution for Category IV B missions will be the subject of a later study.

DeVincenzi, D. L.↗

NASA NTRS2001

Quantitative Studies in Planetary Volcanism

Scientific research was conducted on volcanic processes on Mars, Venus, Io, the moon, and the Earth. The achievements led to scientific advances in the understanding of volcanic plumes, lava flow emplacements, coronae, and regoliths on the solid surfaces. This research led to multiple publications on each of the main topics of the proposal. Research was also presented at the annual Lunar and Planetary Science Conference at Houston. Typically, this grant contributed to 3-4 presentations each year. This grant demonstrated, numerous times, the usefulness of NASA mission data for advancing the understanding of volcanic processes on other planetary surfaces and the Earth.

Baloga, Stephen M.↗

NASA NTRS2000

Dynamic Response of a Planetary Gear System Using a Finite Element/Contact Mechanics Model

The dynamic response of a helicopter planetary gear system is examined over a wide range of operating speeds and torques. The analysis tool is a unique, semianalytical finite element formulation that admits precise representation of the tooth geometry and contact forces that are crucial in gear dynamics. Importantly, no a priori specification of static transmission error excitation or mesh frequency variation is required; the dynamic contact forces are evaluated internally at each time step. The calculated response shows classical resonances when a harmonic of mesh frequency coincides with a natural frequency. However, peculiar behavior occurs where resonances expected to be excited at a given speed are absent. This absence of particular modes is explained by analytical relationships that depend on the planetary configuration and mesh frequency harmonic. The torque sensitivity of the dynamic response is examined and compared to static analyses. Rotation mode response is shown to be more sensitive to input torque than translational mode response.

Parker, Robert G.↗

NASA NTRS2001

Abundances in the Planetary Nebula IC 5217

High resolution optical wavelength spectroscopic data were secured in the optical wavelengths, 3700A - 10,050A, for the planetary nebula IC 5217 with the Hamilton Echelle Spectrograph at Lick Observatory. These optical spectra have been analyzed along with the near-UV and UV archive data. Diagnostic analyses indicate a nebular physical condition with electron temperature of about 10,700 K (from the [O III] lines) and the density of N(sub epsilon) = 5000/cm. Ionic concentrations have been derived with the representative diagnostics, and with the aid of a photoionization model construction, we derived the elemental abundances. Contrary to the previous studies found in the literature, He and C appear to be depleted compared to the average planetary nebula and to the Sun (and S marginally so), while the remaining elements appear to be close to the average value. IC 5217 may have evolved from an O-rich progenitor and the central star temperature of IC 5217 is likely to be 92,000 K.

Hyung, Siek↗

NASA NTRS2001

NASA Regional Planetary Image Facility

The Regional Planetary Image Facility (RPIF) provided access to data from NASA planetary missions and expert assistance about the data sets and how to order subsets of the collections. This ensures that the benefit/cost of acquiring the data is maximized by widespread dissemination and use of the observations and resultant collections. The RPIF provided education and outreach functions that ranged from providing data and information to teachers, involving small groups of highly motivated students in its activities, to public lectures and tours. These activities maximized dissemination of results and data to the educational and public communities.

Arvidson, Raymond E.↗

NASA NTRS2001

Thermal Protection Materials for Reentry and Planetary Applications

Thermal protection materials and systems (TPS) are used to protect spacecraft during reentry into Earth's atmosphere or entry into planetary atmospheres. As such, these materials are subject to severe environments with high heat fluxes and rapid heating. Catalytic effects can increase the temperatures substantially. These materials are also subject to impact damage from micrometeorites or other debris during ascent, orbit, and descent, and thus must be able to withstand damage and function following damage. Thermal protection materials and coatings used in reusable launch vehicles will be reviewed, including the needs and directions for new materials to enable new missions that require faster turnaround and much greater reusability. The role of ablative materials for use in high heat flux environments, especially for non-reusable applications and upcoming planetary missions, will be discussed. New thermal protection system materials may enable the use of sharp nose caps and leading edges on future reusable space transportation vehicles. Vehicles employing this new technology would have significant increases in maneuverability and out-of-orbit cross range compared to current vehicles, leading to increased mission safety in the event of the need to abort during ascent or from orbit. Ultrahigh temperature ceramics, a family of materials based on HfB2and ZrB2 with SiC, will be discussed. The development, mechanical and thermal properties, and uses of these materials will be reviewed.

Johnson, Sylvia M.↗

NASA NTRS1964

Theory of Tumbling Bodies Entering Planetary Atmospheres with Application to Probe Vehicles and the Australian Tektites

The tumbling motion of aerodynamically stable bodies entering planetary atmospheres is analyzed considering that the tumbling, its arrest, and the subsequent oscillatory motion are governed by the equation for the fifth Painleve' transcendent. Results based on the asymptotic behavior of the transcendent are applied to study (1) the oscillatory behavior of planetary probe vehicles in relation to aerodynamic heating and loads and (2) the dynamic behavior of the Australian tektites on entering the Earth's atmosphere, under the hypothesis that their origin was the Moon.

Tobak, Murray↗

NASA NTRS2001

SNOOPY: Student Nanoexperiments for Outreach and Observational Planetary Inquiry

As scientists and engineers primarily employed by the public, we have a responsibility to "communicate the results of our research so that the average American could understand that NASA is an investment in our future...". Not only are we employed by the public, but they are also the source of future generations of scientists and engineers. Teachers typically don't have the time or expertise to research recent advances in space science and reduce them to a form that students can absorb. Teachers are also often intimidated by both the subject and the researchers themselves. Therefore, the burden falls on us - the space scientists and engineers of the world - to communicate our findings in ways both teachers and students can understand. Student Nanoexperiments for Outreach and Observational Planetary InquirY (SNOOPY) provides just such an opportunity to directly involve our customers in planetary science missions.

Kuhlma, K. R.↗

NASA NTRS2001

Stability Analysis of the Planetary System Orbiting Upsilon Andromedae: Simulations Using New Lick Observatory Fits - 2

We present results of long-term numerical orbital integrations designed to test the stability of the three-planet system orbiting upsilon Andromedae and short-term integrations to test whether mutual perturbations among the planets can be used to determine planetary masses. Our initial conditions are based on recent fits to the radial velocity data obtained by the planet search group at Lick Observatory. The new fits result in significantly more stable systems than did the initially announced planetary parameters. Our integrations using the 2000 February parameters show that if the system is nearly planar, then it is stable for at least 100 Myr for m(sub f) = 1/sin i less than or = 4. In some stable systems, the eccentricity of the inner planet experiences large oscillations. The relative periastra of the outer two planets' orbits librate about 0 deg. in most of the stable systems; if future observations imply that the periastron longitudes of these planets are very closely aligned at the present epoch, dynamical simulations may provide precise estimates for the masses and orbital inclinations of these two planets.

Lissauer, Jack J.↗