Planetary Climates

This clear and concise introduction to planetary climates explains the global physical and chemical processes that determine climate on any planet or major planetary satellite—from Mercury to Neptune and even large moons such as Saturn's Titan. The book presents a tour of our solar system's diverse planetary atmospheres, providing a rich foundation on their structure, composition, circulation, climate, and long-term evolution. Although the climates of other worlds are extremely diverse, the chemical and physical processes that shape their dynamics are the same. As this book makes clear, the better we can understand how various planetary climates formed and evolved, the better we can understand Earth's climate history and future. Explaining current knowledge, physical and chemical mechanisms, and unanswered questions, the book brings the reader to the cutting edge of this field.

Dynamics of Artificial Satellites around Europa

A planetary satellite of interest at the present moment for the scientific community is Europa, one of the four largest moons of Jupiter. There are some missions planned to visit Europa in the next years, for example, Jupiter Europa Orbiter (JEO, NASA) and Jupiter Icy Moon Explorer (JUICE, ESA). In this paper, we search for orbits around Europa with long lifetimes. Here, we develop the disturbing potential in closed form up to the second order to analyze the effects caused on the orbital elements of an artificial satellite around Europa. The equations of motion are developed in closed form to avoid expansions in power series of the eccentricity and inclination. We found polar orbits with long lifetimes. This type of orbits reduces considerably the maintenance cost of the orbit. We show a formula to calculate the critical inclination of orbits around Europa taking into account the disturbing potential due to the nonspherical shape of the central body and the perturbation of the third body.

FROZEN ORBITS AROUND EUROPA

Low-altitude, near-polar orbits are very desirable for scientific missions to study the natural satellites of the planets of the Solar System, such as Europa, that is one of the natural satellites of Jupiter. The problem is analyzed considering that an artificial satellite is orbiting Europa and that this spacecraft is perturbed by the nonuniform distribution of mass of the planetary satellite (J2, J3, C22) and by the gravitational attraction of the third-body. We present an analytical theory using the averaged model and applications were done by performing numerical integrations of the analytical equations developed. Using the averaged method, several frozen orbits were obtained. Some of them has low inclination, low altitude and long lifetime. Numerical simulations are performed using the software Mercury, to compare the results obtained using the analytical theory.

The Search for Habitable Worlds: Planetary Exploration in the 21st Century

The search for and detailed characterization of habitable environments on other worlds – places where liquid water, heat/energy sources, and biologically important organic molecules exist or could have once existed – is a major twenty-first-century goal for space exploration by NASA and other space agencies, motivated by intense public interest and highly ranked science objectives identified in recent National Academy decadal surveys. Through telescopic observations, terrestrial laboratory and field studies, and a “flyby, orbit, land, rove, and return” strategy for robotic exploration, particular emphasis will be placed on specific worlds already identified as potentially habitable: Mars, Jupiter's ocean moon Europa, and Saturn's icy and organic-bearing moons Titan and Enceladus. However, the potential abounds for surprising discoveries at many of our solar system's other planetary, satellite, and asteroidal destinations, as well as within newly discovered planetary systems around other stars.