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Saturn remains of the most fascinating planets within the solar system. To better understand the complex ring structure of this planet, a conceptual Saturn Ring Observer (SRO) mission is presented that would spend one year in close proximity to Saturn's A and B rings, and perform detailed observations and measurements of the ring particles and electric and magnetic fields.
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The Cassini spacecraft has been in orbit around Saturn for just over 7 years, with a planned 7-year extension, called the Solstice Mission, which started on September 27, 2010. The Solstice Mission includes 205 maneuvers and 70 flybys which consist of the moons Titan, Enceladus, Dione, and Rhea. This mission is designed to use all available propellant with a statistical margin averaging 0.6 m/s per encounter, and the work done to prove and ensure the viability of this margin is highlighted in this paper.
This paper outlines a mission design for a Saturn Ring Observer (SRO) mission that has Saturn itself provide the bulk of the delta V necessary for orbit insertion, with the remainder within chemical propulsion capability.
Outline: Introduction to the Cassini mission, and Cassini mission Objectives; Cassini spacecraft, instruments, launch, and orbit insertion; Saturn, Rings, and Satellite, Titan; Composite Infrared Spectrometer (CIRS); and Infrared observations of Saturn and titan.
The Cassini mission is a joint NASA-ESA international mission, launched on October 17, 1997 with 12 instruments on board, for exploration of the Saturn system. A composite Infrared Spectrometers is one of the major instruments. Successful insertion of the spacecraft in Saturn's orbit for an extended orbital tour occurred on July 1, 2004. The French Huygens-Probe on board, with six instruments was programmed for a soft landing on Titan's surface occurred in January 2005. The broad range scientific objectives of the mission are: Exploration of the Saturn system for investigations of the origin, formation, & evolution of the solar system, with an extensive range of measurements and the analysis of the data for scientific interpretations. The focus of research dealing with the Cassini mission at NASA/MSFC in collaboration with the NASA/Goddard Space Flight Center, JPL, as well as the research teams at Oxford/UK and Meudon Observatory/France, involves the Infrared observations of Saturn and its satellites, for measurements of the thermal structure and global distributions of the atmospheric constituents. A brief description of the Cassini spacecraft, the instruments, the objectives, in particular with the infrared observations of the Saturn system will be given. The analytical techniques for infrared radiative transfer and spectral inversion programs, with some selected results for gas constituent distributions will be presented.
The Cassini Spacecraft was launched in October 1997 on a mission to observe Saturn and its moons; it entered orbit around Saturn in July 2004 for a nominal four-year Prime Mission, later augmented by two extensions: the Equinox Mission, from July 2008 through September 2010, and the Solstice Mission, from October 2010 through September 2017. This paper provides an overview of the maneuver activities from August 2011 through June 2012 which include the design of 38 Orbit Trim Maneuvers--OTM-288 through OTM-326-- for attaining 14 natural satellite encounters: seven with Titan, six with Enceladus, and one with Dione.
The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year cruise, it entered a Saturnian orbit for a four-year, prime mission. Due to the success of the prime mission, spacecraft health, and remaining propellant, a two-year extended mission, the Equinox Mission, was approved. Maneuver designs and analyses performed through the first year of the Equinox Mission are presented. Results for the 46 most recent maneuvers are given. A substantial contribution to the navigation success of the Cassini-Huygens spacecraft is the continued accurate performance, which has exceeded the pre-launch expectations and requirements.
The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year cruise, it entered a Saturnian orbit for a four-year, prime mission. This paper highlights significant maneuver activities performed during the last year of the prime mission. Specifically, results of 42 recent maneuvers are presented. Many maneuvers have been skipped, saving fuel and flight team effort. The system has performed more accurately than the pre-launch expectations and requirements. This is in large part why the Cassini-Huygens spacecraft has been navigated with tremendous success during the prime mission.
The Cassini-Huygens spacecraft was launched in 1997 on a mission to observe Saturn and its many moons. After a seven-year interplanetary cruise, it entered a Saturnian orbit for a four-year Prime Mission in 2004 and began a two-year Equinox Mission in 2008. It has been approved for another seven-year mission, the Solstice Mission, starting in October 2010. This paper highlights significant maneuver activities performed from July 2009 to June 2010. We present results for the 45 maneuvers during this time. The successful navigation of the Cassini orbiter can be attributed in part to the accurate maneuver performance, which has greatly exceeded pre-launch expectations.
This paper discusses the implementation challenges and lessons learned from radar and radio science pointing observations during the Cassini mission at Saturn. Implementation of the precise desired pointing reveals key issues in the ground system, the flight system, and the pointing paradigm itself. To achieve accurate pointing on some observations, specific workarounds had to be implemented and folded into the sequence development process. Underlying Cassini's pointing system is a remarkable construct known as Inertial Vector Propagation.
Information on the surface mineralogy, chemical composition, and lithology of terrestrial planets, as well as on their atmospheres, that can be obtained by earth-based from visible and NIR spectra of light reflected from planetary surfaces is discussed. Such reflectance spectra may have absorption bands in the 1- and 2-micron wavelength regions which originate from crystal field transitions within Fe(2+) ions. Since pyroxenes with Fe(2+) in M2 positions usually dominate the spectra, the resulting 1-micron vs 2-micron spectral determinative curves can be used to identify compositions and structural types of pyroxenes on the surface of a planet or an asteroid. Future spececraft missions to solar system objects will concentrate on remote-sensing experiments using visible and NIR reflectance spectra. These include the Galileo mission to Jupiter; the Mars Orbiter mission to Phoebus; the Comet Rendezvous Asteroid Flyby mission; the Cassini mission to Saturn; the Lunar Geoscience Observer; and the Mars Rover/Sample Return mission.
Theoretical and observational progress in studies of Saturn's ring system since the mid-1980s is reviewed, focussing on advances in configuration and dynamics, composition and size distribution, dust and meteoroids, interactions of the rings with the planet and the magnetosphere, and relationships between the rings and various satellites. The Cassini instrument suite of greatest relevance to ring studies is also summarized, emphasizing how the individual instruments might work together to solve outstanding problems. The Cassini tour is described from the standpoint of ring studies, and major ring science goals are summarized.
High inclination orbits during Cassini's solstice mission (2012) are providing us with our first observations of Saturn's high latitudes since the prime mission (2007). Since that time, the northern spring pole has emerged into sunlight and the southern autumn pole has disappeared into winter darkness, allowing us to study the seasonal changes occurring within the polar vortices in response to these dramatic insolation changes. Observations from the Cassini Composite Infrared Spectrometer] have revealed (i) the continued presence of small, cyclonic polar hotspots at both spring and autumn poles; and (ii) the emergence of an infrared-bright polar vortex at the north pole, consistent with the historical record of Saturn observations from the 1980s (previous northern spring).
Concept evaluation of manned Earth orbit mission combining Mars flyby and Earth orbital experiments
An overview of an interactive software environment for space mission design termed QUICK is presented. This stand-alone program provides a programmable FORTRAN-like calculator interface to a wide range of both built-in and user defined functions. QUICK has evolved into a general-purpose software environment that can be intrinsically and dynamically customized for a wide range of mission design applications. Specific applications are described for some space programs, e.g., the earth-Venus-Mars mission, the Cassini mission to Saturn, the Mars Observer, the Galileo Project, and the Magellan Spacecraft.
More than 400 years ago, Galileo Galilei trained his homemade telescope on the night sky and observed that Saturn had two objects closely related to the planet extending on either side. At the time, in 1610, Galileo declared them to be moons. A few decades later, Saturn moon science accelerated at a dizzying pace. Christiaan Huygens first observed Saturn's largest moon Titan in 1655 and was the first to describe the extended moon-like features at Saturn as a disk of material sounding the planet. From 1671 to 1674, Giovanni Cassini discovered the moons lapetus, Rhea, Dione and Tethys. In 1675, Cassini discovered the gap in Saturn's rings that we now know as the Cassini Division. In the space age, before the Cassini-Huygens mission, we had only hints of the discoveries awaiting us at Saturn. Pioneer 11 and Voyagers 1 and 2 conducted flybys decades ago. But these quick encounters didn't allow time for more extensive research. NASA and the European Space Agency created a partnership to orbit a Saturn orbiter (Cassini) and a lander (Huygens) on Titan. Like its namesakes, the Cassini-Huygens mission not only discovered previously unknown moons, but it also helped us understand the science behind their formation, their interactions with the rings, and how truly diverse they are. The Cassini-Huygens mission revolutionized what we know about the Saturn system. The rings of Saturn, the moons, and the planet itself offer irresistible and inexhaustible subjects for intense study, and Cassini-Huygens did not disappoint. The Saturnian system proved to be a rich ground for science exploration and discoveries, and Cassini has been nothing short of a discovery machine. At the time Cassini plunged into Saturn at the end of its mission, it had observed the planet for a little less than half of a Saturn year. But it also orbited the gas giant 293 times, forever changing our understanding of the Saturn system and yielding tremendous insight for understanding the entire Solar System.
The Jet Propulsion Laboratory has a long history in the development and application of infrared detector technology for the exploration of our planetary system. We will describe some recent applications of IR detector technology at JPL for ground based astronomy, the Earth Observing System, the Cassini Mission to Saturn, and the other proposed planetary missions. The infrared detector technologies to be discussed include single element, multiplexed linear and staring arrays, using a wide variety of infrared sensing materials including InSb, InGaAs, HgCdTe (PV and PC) and SiAs.