ALBERT

Description: The absolute chronology of Martian rocks and events is based mainly on crater statistics and remains highly uncertain. Martian chronology will be critical to building a time scale comparable to Earth's to address questions about the early evolution of the planets and their ecosystems. In order to address issues and strategies specific to Martian chronology, a workshop was held, 4-7 June 2000, with invited participants from the planetary, geochronology, geochemistry, and astrobiology communities. The workshop focused on identifying: a) key scientific questions of Martian chronology; b) chronological techniques applicable to Mars; c) unique processes on Mars that could be exploited to obtain rates, fluxes, ages; and d) sampling issues for these techniques. This is an overview of the workshop findings and recommendations.

Description: It is vital to include an ultraviolet spectrograph as part of the JIMO payload to Europa, Ganymede and Callisto. Ultraviolet measurements are key for understanding the atmospheres, auroral activity and surfaces of these icy satellites, and a UV imaging spectrograph will also complement a visible camera and near-IR spectrometer, to achieve full wavelength coverage in remote sensing of the icy satellites. The UV instrument proposed for JIMO will be similar to that currently on board the Cassini spacecraft. The design draws on the experience of building UV spectrometers for Mariner, Pioneer, Galileo and Cassini. It will have three spectrographic channels that provide images and spectra of the atmosphere, aurorae and surface: An EUV channel (800-110 nm), an FUV channel (110 to 190 nm) range, and an NUV channel (180 to 350 nm).

Description: Beagle 2 is a 72 kg probe (with a 32 kg lander) developed in the United Kingdom for inclusion on the European Space Agency's 2003 Mars Express. Beagle 2 was launched on June 2, 2003 with Mars Express on a Soyuz-Fregat rocket from the Baikonur Cosmodrome in Kazakhstan. Beagle 2 landed on Mars on December 25th, 2003 in Isidis Planitia (approx. 10.7 N and 268.6 W), a large sedimentary basin that overlies the boundary between ancient highlands and northern plains. Isidis Planitia, the third largest impact basin on Mars, which is possibly filled with sediment deposited at the bottom of long-standing lakes or seas, offers an ideal environment for preserving traces of life. The team is awaiting signals from the Beagle 2 lander at the time when this abstract was written. Current status of the mission will be reported. Beagle 2 was developed to search for organic material and other volatiles on and below the surface of Mars in addition to the study of the inorganic chemistry and mineralogy. Several fundamental properties can be used to determine the existence of an active or past biology on any planet, Earth or Mars. Beagle 2's targets for investigation included: (a) The presence of water, or the existence of minerals deposited from water to show that water was present, even if only transiently; (b) The detection of carbonaceous debris, the remains of organisms that might have lived in water or were washed to a final resting place by the action of water; (c) The structure of organic matter, to demonstrate that it might have been synthesized for a biological purpose; (d) The recognition of isotopic fractionation between carbonaceous phases (organic vs inorganic carbon phases), a condition which on Earth suggests that life emerged nearly 4 billion years ago.

Description: A viewgraph presentation on the discovery of Enceladus water vapor plumes is shown. Conservative modeling of this water vapor is also presented and also shows that Enceladus is the source of most of the water required to supply the neutrals in Saturn's system and resupply the E-ring against losses.

Description: Progress in the development of an instrument for direct geochronologic measurements on rocks in situ will be described. The instrument integrates laser ablation sampling, resonance ionization, and mass spectrometry to directly measure concentrations of the Rb-Sr isotope system. Additional information is contained in the original extended abstract.

Description: We modeled in detail the ejecta dynamics associated with the Chicxulub impact. We determined: (1) ejecta trajectories, (2) stratigraphic motions, (3) depth of ejecta stages, (4) thermodynamic histories of the ejecta particles, and (5) the final ejecta distribution. Additional information is contained in the original extended abstract.

Description: The ability to penetrate subsurfaces and perform sample acquisition at depths of meters is critical for future NASA in-situ exploration missions to bodies in the solar system, including Mars and Europa. A corer/sampler was developed with the goal of acquiring pristine samples by reaching depths on Mars beyond the oxidized and sterilized zone. To developed rotary-hammering coring drill, called Auto-Gopher, employs a piezoelectric actuated percussive mechanism for breaking formations and an electric motor rotates the bit to remove the powdered cuttings. This sampler is a wireline mechanism that is incorporated with an inchworm mechanism allowing thru cyclic coring and core removal to reach great depths. The penetration rate is being optimized by simultaneously activating the percussive and rotary motions of the Auto-Gopher. The percussive mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) mechanism that is driven by piezoelectric stack and that was demonstrated to require low axial preload. The Auto-Gopher has been produced taking into account the a lessons learned from the development of the Ultrasonic/Sonic Gopher that was designed as a percussive ice drill and was demonstrated in Antarctica in 2005 to reach about 2 meters deep. A field demonstration of the Auto-Gopher is currently being planned with objective of reaching as deep as 3 to 5 meters in tufa subsurface.

Description: Few traces of Earth's geologic record are preserved from the time of life's emergence, over 3,800 million years ago. Consequently, what little we understand about abiogenesis - the origin of life on Earth - is based primarily on laboratory experiments and theory. The best geological lens for understanding early Earth might actually come from Mars, a planet with a crust that's overall far more ancient than our own. On Earth, surface sedimentary environments are thought to best preserve evidence of ancient life, but this is mostly because our planet has been dominated by high photosynthetic biomass production at the surface for the last approximately 2,500 million years or more. By the time oxygenic photosynthesis evolved on Earth, Mars had been a hyperarid, frozen desert with a surface bombarded by high-energy solar and cosmic radiation for more than a billion years, and as a result, photosynthetic surface life may never have occurred on Mars. Therefore, one must question whether searching for evidence of life in Martian surface sediments is the best strategy. This Perspective explores the possibility that the abundant hydrothermal environments on Mars might provide more valuable insights into life's origins.

Description: We characterized the impact physics in collisions on porous bodies by various density projectiles and defined different penetration modes (compression, spreading, or breakup) based on transitions between instability regimes. Additional information is contained in the original extended abstract.