Engineering topics
Publications and source records attributed to Bourke, R. D..
NASA will provide the antenna and RF subsystem to the MARSIS radar sounder. There are 11 U.S. Co-Investigators for the science investigations, and navigation and data archiving support are also provided. ASPERA-3 receives NASA Discovery Program funding. Additional information is contained in the original extended abstract.
The United States and Russia have demonstrated serious interests in Mars and are engaged in long-range exploration programs that include launches from each country in 1996. Both countries have conjectured that a more effective, scientifically rewarding program could be realized if their strengths were combined. The paper will describe some of the aspects of the mission and flight system designs along with plans to implement this major international cooperative endeavor.
NASA is in the planning stages of a program leading to the human exploration of Mars. A critical element in that program is a set of robotic missions that will acquire information on the Martian environment and test critical functions (such as aerobraking) at the planet. This paper presents some history of Mars missions, as well as results of recent studies of the Mars robotic missions that are under consideration as part of the exploration program. These missions include: (1) global synoptic geochemical and climatological characterization from orbit (Mars Observer), (2) global network of small meteorological and seismic stations, (3) sample returns, (4) reconnaissance orbiters and (5) rovers.
In the course of the exploration and settlement of the moon, robotic missions will precede and accompany humans. These robotic missions are defined respectively as precursors and adjuncts. Their contribution is twofold: to generate information about the lunar environment (and system performance in that environment), and to emplace elements of infrastructure for subsequent use. This paper describes information that may be gathered by robotic missions and infrastructure elements that may be deployed by them during an early lunar program phase.
The goals of the NASA planetary exploration program are to understand the origin and evolution of the solar system and the earth, and the extent and nature of near-earth space resources. To accomplish this, a number of missions have been flown to the planets, and more are in active preparation or in the planning stage. This paper describes the current and planned planetary exploration program starting with the spacecraft now in flight (Pioneers and Voyagers), those in preparation for launch this decade (Galileo, Magellan, and Mars Observer), and those recommended by the Solar System Exploration Committee for the future. The latter include a series of modest objective Observer missions, a more ambitious set of Mariner Mark IIs, and the very challenging but scientifically rewarding sample returns.
Solar energy has been used for space heating and water heating for many years. A less common application, although technically feasible, is solar cooling. This paper describes the techniques employed in the heating and cooling of buildings, and in water heating. The potential for solar energy to displace conventional energy sources is discussed. Water heating for new apartments appears to have some features which could make it a place to begin the resurgence of solar energy applications in the United States. A project to investigate apartment solar water heating, currently in the pilot plant construction phase, is described.
Following the cancellation of the Outer Planet Grand Tour Project, NASA and JPL examined less ambitious, alternative missions for exploring the outer planets. The mission that proved most attractive scientifically and fits within the projected NASA budget constraints embraces dual flights to Jupiter and Saturn, with launch in 1977. NASA has implemented it as the Mariner Jupiter/Saturn 1977 (MJS77) Project. The MJS77 mission covers exploratory investigations of the Jupiter and Saturn planetary systems and the interplanetary medium out to Saturn. Items of special interest include Jupiter's great red spot, the question of Io's anomalous brightening and phenomena associated with its EM behavior. After Saturn encounter, the spacecraft will escape the solar system in the general direction of the solar apex.
Current plans of NASA are to take advantage of the 1977 launch opportunity by sending a Mariner class spacecraft on a gravity assisted flyby of Jupiter which will then continue on to Saturn. The background of this Mariner Jupiter-Saturn 77 Project is reviewed and science objectives for this mission as currently adapted are given. This paper illustrates properties of the Jupiter-Saturn opportunities between 1976 and 1980 to give context to the 1977 opportunity. Details of the possibilities for the 1977 launch are shown along with constraints and example candidate trajectories. Options include close flybys and/or occultations of the satellites at Jupiter and Saturn, penetration of Saturn's rings, and various occultations of the planets. A short discussion of other factors, such as navigation and planetary quarantine (documented elsewhere) are included.
Multitarget flyby missions to asteroids and comets are attractive candidates for solar electric propulsion (SEP) application because SEP can efficiently provide the thrust required for carefully chosen sequences of encounters. In this paper, techniques for finding encounter sequences for these missions are described, and examples involving flyby and rendezvous missions to P/Encke, P/Kopff and 20/Massalia are presented. In addition, examples of four asteroid flyby sequences are given. Encounters typically have flyby speeds on the order of 5-10 km/sec and are limited only by navigational capability as regards flyby distance, which is taken as zero in the study. Flights traversing the asteroid belt can be modified by SEP to pass one or more asteroids, and the performance penalty is small if the encounters are properly spaced.
Current estimates of solar-electric-propulsion spacecraft performance are based upon a solar-array output power which is degraded by approximately 10-13% to account for possible losses caused by proton, electron and micrometeorite damage. Past studies have used a worst case analysis in which the maximum degradation was taken to occur at the beginning of the mission. This paper presents a comparison of mission studies using a hypothetical exponential decrease in power with time, with those using a sudden degradation of solar power. These comparisons indicate that the performance gain by using a time varying degradation during the mission is quite small for outbound missions in the solar system. In addition an indication of the power allocation strategy to be followed during a mission is presented.
Mariner mission to Venus and Mercury in 1973, discussing special opportunity characteristics, mission options, real time TV picture transmission, trajectory analysis, etc
Grand Tour mission design, discussing navigation, trajectory parameters, launch vehicles and satellite flybys
Mission planning for 1973 Mariner Venus/Mercury flyby, discussing trajectory and navigation aspects
Translational forces on Mariner 5 stemming from attitude control system, determining trajectory for scientific and operational purposes
Mariner 5 flight path and its determination from tracking data
Translational forces on Mariner 5 stemming from attitude control system studied to determine trajectory for scientific and operational purposes
First generation survivable lander for 1973 Venus launch opportunity, discussing capsule and telecommunications design