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At least 937 records · Page 52

Jovian system science issues and implications for a Mariner Jupiter Orbiter mission

Science goals for missions to Jupiter in the early 1980's are reviewed and a case is made for the science community to play the key role in assigning relative priorities for these goals. A reference set of measurement requirements and their priorities is established and those high priority goals that are most demanding on spacecraft and mission design are used to develop a reference mission concept. An orbiter mission is required to satisfy a majority of the measurements, and a spacecraft data handling capability as least equivalent to the Mariner Jupiter/Saturn spacecraft is the major system design driver. This reference Mission Concept is called Mariner Jupiter Orbiter. The remaining measurement requirements are reviewed in light of the potential science return of this mission, and certain options are developed to augment this science return. Two attractive options fulfill high priority objectives not achieved by the reference Mariner Jupiter Orbiter mission alone: an atmospheric entry probe, released prior to orbit insertion; and a daughter satellite dedicated to particle and fields measurements, ejected into an independent orbit about Jupiter.

Beckman, J. C.↗

Analysis of extended-duration sortie missions

Many Spacelab payloads could significantly benefit from an extension of the duration of sortie missions beyond the nominal seven days. However, longer sortie missions require the addition of Shuttle or Spacelab mission extension kits, which results in a significant reduction in allowable scientific payload weight. An analysis of extended-duration sortie missions was performed. Payload requirements and detailed descriptions of Shuttle and Spacelab baselines were the primary inputs to the analysis. Payload benefits from extended-duration missions were established by surveying payload requirements and interviewing discipline specialists. The net weight available to Spacelab payloads as a function of mission length was derived. The impacts on Shuttle and Spacelab to provide extended-duration mission support and the corresponding impacts on payloads were established. Several alternatives to baseline systems and operations were studied as possibilities to increase available payload weight.

Ring, R. C.↗

Planetary missions in the Shuttle era

A conservative fifteen-year plan for planetary exploration is presented in which the Space Shuttle is considered as just a basic transportation system that should be quite economical and have excellent reliability. It is noted that these planned missions are limited by the out-of-orbit escape capability of the Shuttle's Interim Upper Stage (IUS), rather than by the orbital payload capability of the Shuttle itself. A mission model is provided in which a rather even balance is maintained among missions to the inner planets, the outer planets, the comets and asteroids, and interplanetary missions out of the ecliptic plane; the cost estimate for this model is plotted. Launch requirements for the various missions are compared with the performance available from various IUS candidates under evaluation, and it is shown that even the lower-performance candidates can be brought up to the capability of the current Titan IIIE/Centaur/TE-364 expendable launch vehicle, which is adequate for most of the missions in the program. Missions which require higher-performance IUS options are noted, including the Mariner Jupiter and Saturn Orbiters.

Kraemer, R. S.↗

Automated missions of the future

The paper discusses how Goddard Space Flight Center is dealing with the problem of undertaking new space missions within the limitations of severe funding constraints by using the same basic modularized spacecraft for all major earth-observation and astronomy missions of the 1980s. The basic spacecraft is described in the context of the Solar Maximum Mission, with emphasis on the transition adapter, attitude-control module, power module, communications and data-handling module, propulsion module, launch vehicles, and redundancy. The costs associated with the basic spacecraft and transportation are compared for two modes: four spacecraft and four separate launches for four missions and two resuppliable spacecraft for the same four missions. It is concluded that the most cost-effective means of sustaining a long-term astronomy or earth-observation mission is to service the mission in space.

Purcell, J.↗

Early Spacelab missions

NASA has issued payload flight assignments for the first three Spacelab missions. The first two of these missions will have dual objectives, that of verifying Spacelab system performance and accomplishing meaningful space research. The first of these missions will be a joint NASA and ESA mission with a multidisciplinary payload. The second mission will verify a different Spacelab configuration while addressing the scientific disciplines of astrophysics. The third assigned mission will concentrate on utilizing the capabilities of Spacelab to perform meaningful experiments in space applications, primarily space processing. The paper describes these missions with their objectives, planned configuration and accommodation.

Pace, R. E., Jr.↗

Outer planets exploration - A mission strategy for the 1980's

This paper presents a mission strategy for exploring the outer planets in the 1980s. The strategy is based on the anticipated findings of the 1977 Voyager Jupiter/Saturn Mission, and the 1982 Jupiter Orbiter Probe (JOP) Mission, recently approved as a new project start, beginning in October 1977. The JOP Mission then becomes a principal element in the strategy presented here. Characteristics (launch energy, trajectory parameters, etc.) of other mission opportunities to the outer planets in the 1980s are developed and presented. The need for and benefits from advanced propulsion systems, which can enable the more difficult missions to the outer planets, also are cited. The overall mission strategy, including a description of the options, is evolved in consideration of scientific rationale and return, and technical and programmatic coupling factors.

Moore, J. W.↗

Advanced solar space missions

The space missions in solar physics planned for the next decade are similar in that they will have, for the most part, distinct, unifying science objectives in contrast to the more general 'exploratory' nature of the Orbiting Solar Observatory and Skylab/ATM missions of the 1960's and 70's. In particular, the strategy for advanced solar physics space missions will focus on the quantitative understanding of the physical processes that create and control the flow of electromagnetic and particulate energy from the sun and through interplanetary space at all phases of the current sunspot cycle No. 21. Attention is given to the Solar Maximum Mission, the International Solar Polar Mission, solar physics on an early Shuttle mission, principal investigator class experiments for future spacelabs, the Solar Optical Telescope, the Space Science Platform, the Solar Cycle and Dynamics Mission, and an attempt to send a spacecraft to within 4 solar radii of the sun's surface.

Bohlin, J. D.↗

Forecasting of loading on the Deep Space Network for proposed future NASA mission sets

The paper describes a computer program, DSNLOAD, which provides the Deep Space Network (DSN) loading information given a proposed future NASA mission set. The DSNLOAD model includes required pre- and post-calibration periods, and station 'overhead' such as maintenance or 'down' time. The analysis is presented which transforms station view period data for the mission set into loading matrices used to assess loading requirement. Assessment of future loading on the DSN for a set of NASA missions by estimating the tracking situation and presenting the DSN loading data, and a flowchart for selecting a possible future mission, determining a heliocentric orbit for the mission, generating view period schedules, and converting these schedules into basic loading data for each mission for each station are given. The tracking schedule model which considers the tracking schedule to be represented by passes of maximum required length and centered within the view period of available tracking time for each mission is described, and, finally, an example of typical loading study is provided.

Webb, W. A.↗

Manned Orbital Transfer Vehicle (MOTV). Volume 2: Mission handbook

The use of the manned orbit transfer vehicle (MOTV) for support of future space missions is defined. Some 20 generic missions are defined each representative of the types of missions expected to be flown in the future. These include the service and update of communications satellites, emergency repair of surveillance satellites, and passenger transport of a six man crew rotation/resupply service to a deep space command post. The propulsive and functional capabilities required of the MOTV to support a particular mission are described and data to enable the user to determine the number of STS flights needed to support the mission, mission peculiar equipment requirements, parametrics on mission phasing and requirements, ground and flight support requirements, recovery considerations, and IVA/EVA trade analysis are presented.

Boyland, R. E.↗

A review of Spacelab mission management approach

The Spacelab development program is a joint undertaking of the NASA and ESA. The paper addresses the initial concept of Spacelab payload mission management, the lessons learned, and modifications made as a result of the actual implementation of Spacelab Mission 1. The discussion covers mission management responsibilities, program control, science management, payload definition and interfaces, integrated payload mission planning, integration requirements, payload specialist training, payload and launch site integration, payload flight/mission operations, and postmission activities. After 3.5 years the outlined overall mission manager approach has proven to be most successful. The approach does allow the mission manager to maintain the lowest overall mission cost.

Craft, H. G., Jr.↗

Infrared focal plane arrays for planetary missions

Requirements for infrared detector array focal planes suitable for a set of prospective planetary missions are developed. Using the Galileo mission to Jupiter as a starting point, objectives and constraints applicable to outer planet missions are developed. The concept for an advanced mapping spectrometer utilizing 128 x 128 element infrared detector arrays is described. Specific implementations for the Saturn Orbiter Dual Probe mission, a Mars Orbiter mission, and a Titan Orbiter mission are defined. The analysis indicates that within the 1 to 5 micron range, broad scientific objectives for these missions can be met using focal plane arrays with detectivities on the order of 10 to the 14th cm sq root of Hz per W. The realization of such high detectivities in a low background application will necessitate careful development of the method by which the detector signals are multiplexed and read out.

Wellman, J. B.↗

Some significant considerations in the planning of sortie missions

Opportunities and limitations to be considered in the planning of Space Shuttle/Spacelab sortie missions are discussed. As shown by a simple model of the flow of STS equipment through ground processing and flights under ideal conditions, mission duration is constrained by Orbiter availability, which is determined initially by the Orbiter production schedule and the turnaround time required between missions, and by the usage rate and quantity limitations of mission consumables. Additional considerations affecting mission duration include reductions in crew productivity upon increased mission duration and crew size, spacecraft and experiment degradation, equipment and processing facility cost effectiveness, and requirements for a power extension package, which considerations imply that increased allowable landing weight would make co-manifesting (the combination of Spacelab and deliverable payload missions) more attractive. Advantages related to payload recoverability, human presence, ease of access and the availability of different orbits are also pointed out.

Loftus, J. P., Jr.↗

Mission options for the first SEPS application

Missions to comets and asteroids are primary candidates for Solar Electric Propulsion System (SEPS) applications. NASA estimates that the first SEPS mission might be launched as early as 1988. This paper presents mission opportunities available for launches between 1988 and early 1991 and discusses the performance capabilities of the current SEPS. Use of a Shuttle Two-Stage IUS and/or a Shuttle Wide Tank Centaur launch vehicle is assumed in the performance assessment. The list of possible first SEPS missions consists of nine missions to comets of primary interest and examples of multiple asteroid rendezvous missions. Both an earth crossing asteroid and a main belt asteroid are considered as first possible targets in the multiple asteroid rendezvous examples. Mission opportunity and performance maps for Eros and Anteros are presented which provide exact performance data and optimal launch and arrival dates for any launch year.

Yen, C.-W. L.↗

Space Station needs, attributes and architectural options. Volume 2, book 1, part 2, task 1: Mission requirements

Mission areas analyzed for input to the baseline mission model include: (1) commercial materials processing, including representative missions for producing metallurgical, chemical and biological products; (2) commercial Earth observation, represented by a typical carry-on mission amenable to commercialization; (3) solar terrestrial and resource observations including missions in geoscience and scientific land observation; (4) global environment, including representative missions in meteorology, climatology, ocean science, and atmospheric science; (5) materials science, including missions for measuring material properties, studying chemical reactions and utilizing the high vacuum-pumping capacity of space; and (6) life sciences with experiments in biomedicine and animal and plant biology.

Source record↗

Performance assessment of planetary missions as launched from an orbiting space station

Results presented are intended to assist planners and the mission analysis community in assessing the performance impact (pro or con) of launching planetary missions from an orbiting space station as compared to the usual, ground-based Shuttle launch of such missions. The analyses comprising this assessment include: (1) a basic understanding and description of the space station launch problem; (2) examination of alternative injection strategies and selection of the most appropriate strategy for minimizing performance penalties; and (3) quantitative comparison of station-launched and Shuttle-launched performance over a wide energy/mass range of planetary mission opportunities. Data for each mission covers a full 360 deg of possible nodal location of the space station orbit. The main results are that planetary missions can be launched from a space station within acceptable penalty bounds, and that the station serving as a staging base/propellant depot can benefit some missions requiring large payload mass or high injection energy.

Friedlander, A.↗

Mission opportunity maps for rendezvous with earth-crossing asteroids

Rendezvous missions for earth-crossing asteroids are of interest to NASA, for scientific purposes as well as for technological applications and ecological implications. To provide a comprehensive data base for planners of such missions, a mission opportunity map (MOM) has been created for eight relatively easy-to-access asteroids. A MOM presents such mission data as launch dates, flight times, and launch and postlaunch delta-V requirements for all useful mission opportunities. The merits of a MOM are: (1) searches for all useful mission opportunities are completed in the process of generating a MOM, and (2) a clear view of good and bad opportunities, the extent of performance variations, and the repeatability of the missions.

Yen, C.-W. L.↗

Ballistic comet exploration mission options

Trajectory options and mission opportunities of cometary rendezvous missions begining in 1990 are explored. The study is constrained to the capabilities of the Mariner Mark II multi-mission spacecraft, Shuttle launch and Centaur G-prime boost. The mission would be targeted at collecting an atomized sample, near the comet perihelion, and returning the sample for analysis. Mission trajectories, launch dates, payload masses and flight durations are provided for 13 comets. All missions would take from 4-8 yr and deliver a 600-2000 kg payload. A survey of mission opportunities involving Jupiter gravity assists is also presented.

Yen, C.-W. L.↗

Nuclear electric propulsion missions

This paper reviews nuclear electric propulsion technology and missions. The science objectives and mission performance of the following five missions are presented: (1) Neptune orbiter, (2) Saturn ring rendezvous, (3) an asteroid sample return, (4) a comet sample return, and (5) an interstellar precursor mission. A short status of the reactor and thermal to electric conversion technologies is given as well as a brief discussion of ion thruster technology. A specific nuclear reactor power system concept is presented that produces 100 kWe and has a mass of about 2600 kg. Mission performance in terms of payload and flight time is presented for all five missions. Heliocentric trajectories are presented for the Neptune orbiter, Saturn ring rendezvous, and Comet Tempel 2 nucleus sample return missions.

Jones, R. M.↗