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Clark, Karla

Publications and source records attributed to Clark, Karla.

8 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Enceladus Life Finder: the Search for Life in a Habitable Moon

Enceladus is one of the most intriguing bodies in the solar system. In addition to having one of the brightest and youngest surfaces, this small Saturnian moon was recently discovered to have a plume erupting from its south polar terrain and a global subsurface ocean. The Cassini Mission discovered organics and nitrogen-bearing molecules in the plume, as well as salts and silicates that strongly suggest ocean water in contact with a rocky core. However, Cassini's instruments lack sufficient resolution and mass range to determine if these organics are of biotic origin. The Enceladus Life Finder (ELF) is a Discovery-class mission that would use two state-of-the-art mass spectrometers to target the gas and grains of the plume and search for evidence of life in this alien ocean.

Saturn↗
NASA NTRS2010

Engineering a Solution to Jupiter Exploration

The Europa Jupiter System Mission (EJSM) would be an international mission with the overall theme of investigating the emergence of habitable worlds around gas giants. Its goals are to (1) explore Europa to investigate its habitability, (2) characterize Ganymede as a planetary object including its potential habitability and (3) explore the Jupiter system as an archetype for gas giants. NASA and ESA have concluded a detailed joint study of a mission to Europa, Ganymede, and the Jupiter system with conceptual orbiters developed by NASA and ESA. The baseline EJSM architecture consists of two primary elements operating simultaneously in the Jovian system: the NASA-led Jupiter Europa Orbiter (JEO), and the ESA-led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute an intricately choreographed exploration of the Jupiter System before settling into orbit around Europa and Ganymede, respectively. EJSM would directly address themes concerning the origin and evolution of satellite systems and water-rich environments in icy satellites. The potential habitability of the ocean-bearing moons Europa and Ganymede would be investigated, by characterizing the geophysical, compositional, geological, and external processes that affect these icy worlds. EJSM would also investigate Io and Callisto, Jupiter's atmosphere, and the Jovian magnetosphere. By understanding the Jupiter system and unraveling its history, the formation and evolution of gas giant planets and their satellites would be better known. Most importantly, EJSM would shed new light on the potential for the emergence of life in the celestial neighborhood and beyond. The EJSM baseline architecture would provide opportunities for coordinated synergistic observations by JEO and JGO of the Jupiter and Ganymede magnetospheres, the volcanoes and torus of Io, the atmosphere of Jupiter, and comparative planetology of icy satellites. Each spacecraft would conduct both synergistic dual-spacecraft investigations and stand-alone measurements toward the overall mission theme and goals.

Clark, Karla↗
NASA NTRS2008

Estimating the Reliability of Electronic Parts in High Radiation Fields

Radiation effects on materials and electronic parts constrain the lifetime of flight systems visiting Europa. Understanding mission lifetime limits is critical to the design and planning of such a mission. Therefore, the operational aspects of radiation dose are a mission success issue. To predict and manage mission lifetime in a high radiation environment, system engineers need capable tools to trade radiation design choices against system design and reliability, and science achievements. Conventional tools and approaches provided past missions with conservative designs without the ability to predict their lifetime beyond the baseline mission.This paper describes a more systematic approach to understanding spacecraft design margin, allowing better prediction of spacecraft lifetime. This is possible because of newly available electronic parts radiation effects statistics and an enhanced spacecraft system reliability methodology. This new approach can be used in conjunction with traditional approaches for mission design. This paper describes the fundamentals of the new methodology.

radiation↗
NASA NTRS2008

Assessment of Alternative Europa Mission Architectures

The purpose of this study was to assess the science merit, technical risk and qualitative assessment of relative cost of alternative architectural implementations as applied to a first dedicated mission to Europa. The objective was accomplished through an examination of mission concepts resulting from previous and ongoing studies. Key architectural elements that were considered include moon orbiters, flybys (single flybys like New Horizons and multiple flybys similar to the ongoing Jupiter System Observer study), sample return and in situ landers and penetrators.

Juptier Icy Moon Orbiter (JIMO)↗
NASA NTRS2007

Europa Explorer: 2008 Study Approach

This viewgraph presentation reviews the Europa Explorer. The contents include: 1) Science and TMC Panel Comments; 2) 2008 Study Ground Rules; and 3) Approach for Meeting New Ground Rules.

Europa↗
NASA NTRS1991

The CRAF/Cassini power subsystem - Preliminary design update

A chronology is provided of the rationale leading from the early Mariner spacecraft to the CRAF/Cassini Mariner Mark II power subsystem architecture. The display pathway began with a hybrid including a solar photovoltaic array, a radioisotope thermoelectric generator (RTG), and a battery supplying a power profile with a peak loading of about 300 W. The initial concept was to distribute power through a new solid-state, programmable switch controlled by an embedded microprocessor. As the overall mission, science, and project design matured, the power requirements increased. The design evolved from the hybrid to two RTG plus batteries to meet peak loadings of near 500 W in 1989. Later that year, circumstances led to abandonment of the distributed computer concept and a return to centralized control. Finally, as power requirements continued to grow, a third RTG was added to the design and the battery removed, with the return to the discharge-controller for transients during fault recovery procedures.

Atkins, Kenneth L.↗