Outward to the Beginning: the CRAF and Cassini Missions of the Mariner Mark 2 Program

Two successive journeys will soon offer a perspective on the origin of the solar system and perhaps provide clues on the origin of life as well. The missions, the Comet Rendezvous Asteroid Flyby (CRAF) and Cassini (the Saturn orbiter/Titan probe), combine to form the first initiative of the Mariner Mark 2 program, a series of planetary missions whose common objective is to explore primitive bodies and the outer solar system, toward the ultimate goal of understanding the nature of our origins. Cassini and CRAF are exciting planetary missions. The objectives that they share, the region of the solar system in which comets, asteroids, and the Saturnian system have evolved and now reside, and the spacecraft that will carry both sets of experiments to their targets in the outer solar system are described

Highlights of 1981 activities

The highlights of NASA's 1981 activities are presented, including the results of the two flights of the space shuttle Columbia and the Voyager 2 encounter with Saturn. Accomplishments in the areas of space transportation operations; space science; aeronautical, energy, and space research and development; as well as space tracking, international activities, and 1981 launch activities are discussed

International Collaboration in Lunar Exploration

The U.S. Vision for Space Exploration commits the United States to return astronauts to the moon by 2020 using the Ares I Crew Launch Vehicle and Ares V Cargo Launch Vehicle. Like the Apollo program of the 1960s and 1970s, this effort will require preliminary reconnaissance in the form of robotic landers and probes. Unlike Apollo, some of the data NASA will rely upon to select landing sites and conduct science will be based on international missions as well, including SMART-1, SELENE, and Lunar Reconnaissance Orbiter (LRO). Opportunities for international cooperation on the moon also lie in developing lunar exploration technologies. The European Space Agency's SMART-1 orbiter (Figure 1) is making the first comprehensive inventory of key chemical elements in the lunar surface. It is also investigating the impact theory of the moon's formation.

Fuzzy-PID Controller for Azimuth Position Control of Deep Space Antenna

The Deep Space Antennas are essential in achieving communication over very large distances. However, the pointing accuracy of this antenna needs to be as precise as possible to enable effective communication with the satellite. Therefore, this work addressed the pointing accuracy for a Deep Space Antenna using Fuzzy-PID control technique by improving the performance objectives (settling time, percentage overshoot rise time and mainly steady-state error) of the system. In this work, the PID controller for the system was first of all designed and simulated after which, a fuzzy controller was also designed and simulated using MATLAB and Simulink respectively for the sake of comparison with the fuzzy-PID controller. Then, the fuzzy-PID controller for the system was also designed and simulated using MATLAB and Simulink and it gives a better performance objective (rise time of 1.0057s, settling time of 1.6019s, percentage overshoot of 1.8013, and steady-state error of 2.195e-6) over the PID and fuzzy controllers respectively. Therefore, the steady state error shows improved pointing accuracy of 2.195e-6

NASA: 1986 long-range program plan

For the years beyond FY 1986, the plan consists of activities that are technologically possible and considered to be in the national interest. Its implementation will ensure logical and continued progress in reaching the Nation's goals in aeronautics and space, consistent with the responsibilities assigned NASA by the National Aeronautics and Space Act of 1958, as amended. The major features of the programs are described in detail and the nature of the aeronautics and space programs beyond the year 2000 are projected. The abbreviations and acronyms that appear in this report are listed. The status of NASA's plans are summarized at the time of its preparation

The NASA Ground Network Vision for the Future

This paper will highlight the GN's mission, motivation, and future plans, specifically in relation to the increase of commercialization for routine services and partnership opportunities for routine and unique services with the goal that other agencies can benefit from our approach as they pursue their science and exploration goals

Vortex Radiometry: Fundamental Concepts

Vortex radiometers (VRs) enable communication systems to maximize data throughput by determining when to employ fade mitigation most efficiently. With this information, communication systems can optimize mitigation strategies before actual fades occur. Doing so maximizes the time over which the link is available, and therefore maximizes data throughput. This paper presents the fundamental concepts of vortex radiometry, including the creation of annular beam patterns through the use of orbital angular momentum (OAM). These concepts are simulated on a 100 Mbps (Megabits per second) GEO (Geosynchrous Earth Orbit)-to-ground Ka-Band communication link. During the simulation a noise source traverses across the link, and without VR capabilities the link is disrupted. However, when the situation is repeated with VR capabilities enabled, the antenna is able to increase receiver gain and maintain the link. VRs are uniquely suited to provide communication systems with the ability to optimize receiver parameters and maximize data throughput, making them critical to enabling next generation communication networks

Biospheres and solar system exploration

The implications of biosphere technology is briefly examined. The exploration status and prospects of each world in the solar system is briefly reviewed, including the asteroid belt, the moon, and comets. Five program elements are listed as particularly critical for future interplanetary operations during the coming extraterrestrial century. They include the following: (1) a highway to Space (earth orbits); (2) Orbital Spaceports to support spacecraft assembly, storage, repair, maintenance, refueling, launch, and recovery; (3) a Bridge Between Worlds to transport cargo and crews to the moon and beyond to Mars; (4) Prospecting and Resource Utilization Systems to map and characterize the resources of planets, moons, and asteroids; and (5) Closed Ecology Biospheres. The progress in these five field is reviewed

NASA historical data book. Volume 2: Programs and projects 1958-1968

This is Volume 2, Programs and Projects 1958-1968, of a multi-volume series providing a 20-year compilation of summary statistical and other data descriptive of NASA's programs in aeronautics and manned and unmanned spaceflight. This series is an important component of NASA published historical reference works, used by NASA personnel, managers, external researchers, and other government agencies