Atmospheric Escape and Evolution of Terrestrial Planets and Satellites

The origin and evolution of Venus’, Earth’s, Mars’ and Titan’s atmospheres are discussed from the time when the active young Sun arrived at the Zero-Age-Main-Sequence. We show that the high EUV flux of the young Sun, depending on the thermospheric composition, the amount of IR-coolers and the mass and size of the planet, could have been responsible that hydrostatic equilibrium was not always maintained and hydrodynamic flow and expansion of the upper atmosphere resulting in adiabatic cooling of the exobase temperature could develop. Furthermore, thermal and various nonthermal atmospheric escape processes influenced the evolution and isotope fractionation of the atmospheres and water inventories of the terrestrial planets and Saturn’s large satellite Titan efficiently.     

LISA: Heliocentric formation design for the laser interferometer space antenna mission

The LISA (Laser Interferometer Space Antenna) mission has been selected by the European Space Agency’s Science Programme Committee as the third large-class mission of the Cosmic Vision Programme, addressing the science theme of the Gravitational Universe. With a planned launch date in 2034, LISA will be the first ever space-borne Gravitational Wave observatory, relying on laser interferometry between three spacecraft orbiting the Sun in a triangular formation. Airbus is currently leading an industrial Phase A system study on behalf of the European Space Agency. The paper will address the astrodynamics challenges associated with the LISA constellation design, driven by tight requirements on the geometric quality metrics of the near equilateral formation.     

Trust and decision-making: An empirical platform (CCP 204)

The trust literature emphasizes trust in automation, thus neglecting the interpersonal aspects of how distributed personnel develop trust. Interpersonal trust represents the willingness of individuals to accept vulnerabilities from the actions of others. Vulnerability is a critical aspect of trust research, yet few studies have manipulated vulnerability. Non-verbal cues may have an influence on the trust process, suggesting that features of collaborative tools may influence how individuals build trust. The present study will implement a 3 x 4 mixed design. Participants will select a convoy route based on: * 1) graphical displays of enemy zones and historical Improvised Explosive Device (lED) occurrences; * 2) route parameters (e.g., fuel required); and * 3) information from a local expert. Vulnerability will be manipulated by altering the frequency of TEDs and the location of "red forces" to create low, moderate, and high vulnerability conditions (within subjects factor). Information from local experts will be presented via one of four conditions: * 1) audio/video with low emotion; * 2) audio/video with high emotion; ,, 3) audio only; and * 4) chat (between subjects factor). Findings from this research will support the development of new collaborative tools for the Command and Control (C2) domain.     

Data From the Precision Solar Photometric Telescope (Pspt) in Hawaii From March 1998 to March 1999

Two Precision Solar Photometric Telescopes (PSPT) designed and built at the U.S. National Solar Observatory (NSO) are in operation in Rome and Hawaii. A third PSPT is now in operation the NSO at Sunspot, NM. The PSPT system records full disk solar images at three wavelengths: K line at 393.3 nm and two continua at 409 nm and 607 nm throughout the observing day. We currently study properties of limb darkening, sunspots, and network in these images with particular emphasis on data taken in July and September 1998. During this period, the number of observations per month was high enough to show directional properties of the radiation field surrounding sunspots. We show examples of our PSPT images and describe our study of bright rings around sunspots.     

Understanding microbialite morphology using a comprehensive suite of three-dimensional analysis tools

Microbialites can have complex morphologies that preserve clues to ancient microbial ecology. However, extracting and interpreting these clues is challenging due to both the complexity of microbial structures and the difficulties of connecting morphology to microbial processes. Fenestrate microbialites from the 2521±3 Ma Gamohaan Formation, South Africa, have intricate structures composed of three distinct microbial structures: steeply dipping supports (surfaces defined by organic inclusions), more shallowly dipping supports with diffuse organic inclusions below them, and draping laminae. In polished slabs, shallowly dipping supports with diffuse organic inclusions show apparent dips from 27° to 60°, and supports without associated zones of diffuse inclusions dip 75° to 88°, which suggests a distinction between support types based on orientation. However, dips exposed in polished slabs are apparent dips, and three-dimensional analysis is required for analysis of true dips. Through the Keck Center for Active Visualization in Earth Sciences (KeckCAVES), we used locally developed software that controls a three-dimensional environment with head and hand tracking (an "immersive environment") to visualize and interpret virtual microbialite data sets. Immersive environments have not penetrated into standard scientific work processes ("workflows") due to their high costs, steep learning curves, and low productivity for users. By contrast, our suite of software tools allowed us to develop a personalized scientific workflow that provides a complete path from initial ideas to characterization of fenestrate microbialites' features. Results of three-dimensional analysis of fenestrate microbialites show that supports with inclusions dip 65° to 75°, whereas supports without inclusions dip 85° to 90°. These results demonstrate that all supports have very steep dips, and a 10° dip gap exists between supports with and without inclusions, which suggests they grew in fundamentally different ways. Results also emphasize how valuable three-dimensional analysis is when combined with a comprehensive workflow for understanding intricate structures such as fenestrate microbialites.     

Initial characterization of the microgravity environment of the international space station: increments 2 through 4

The primary objective of the International Space Station (ISS) is to provide a long-term quiescent environment for the conduct of scientific research for a variety of microgravity science disciplines. This paper reports to the microgravity scientific community the results of an initial characterization of the microgravity environment on the International Space Station for increments 2 through 4. During that period almost 70,000 hours of station operations and scientific experiments were conducted. 720 hours of crew research time were logged aboard the orbiting laboratory and over half a terabyte of acceleration data were recorded and much of that was analyzed. The results discussed in this paper cover both the quasi-steady and vibratory acceleration environment of the station during its first year of scientific operation. For the quasi-steady environment, results are presented and discussed for the following: the space station attitudes Torque Equilibrium Attitude and the X-Axis Perpendicular to the Orbital Plane; station docking attitude maneuvers; Space Shuttle joint operation with the station; cabin de-pressurizations and the station water dumps. For the vibratory environment, results are presented for the following: crew exercise, docking events, and the activation/de-activation of both station life support system hardware and experiment hardware. Finally, a grand summary of all the data collected aboard the station during the 1-year period is presented showing where the overall quasi-steady and vibratory acceleration magnitude levels fall over that period of time using a 95th percentile benchmark.     

The ‘promise’ of smart materials for small satellites

In this paper the potential use of ‘smart’ materials to improve the performance and cost efficiency of small satellites is introduced. The basic operating performance of the structural smart materials are reviewed as are some of the foreseen application areas. The state of the art in applying smart materials for use in space is then discussed with a focus on areas where information is lacking. A series of actions to alleviate these shortcomings are proposed and some current activities of the DLR-Institute of Structural Mechanics to answer these calls for action are highlighted.