DESIGNED MISSION

Here we briefly mention engineering tools in the areas of concept design, mission assurance, and software engineering that have been developed for use at The Aerospace Corporation to address program risk issues on space system development projects. 

Survivability is the capability of a system and crew to avoid or withstand a man-made hostile environment without suffering an abortive impairment of its ability to accomplish its designated mission. Survivability consists of susceptibility, vulnerability, and recoverability. 

UMS is an electromechanical system that is able to exert its power to perform designed missions and includes the following four common characteristics ... 

Project An integrated set of Systems that accomplish the Prometheus Program Objectives Project Engineering Science Mission Design Mission Assurance Safety... 

A Garett (now Honeywell) study estimated failure rates for space Brayton systems. The estimated failure rates for relevant components of a Prometheus mission are shown in Table 9-5. Based upon their values, a reliability rate of "99.6% for a 3 year mission and "97% for a 20 year mission are inferred. While these values are only rough estimates based upon open cycle experience not directly related to the Prometheus design/mission, it indicates that high reliability rates are believed achievable, even for longer life missions. 

Special uses iaclude oxygen for fuels iatended for long-term unattended service (13). Candles are fired on demand by a pressure sensor ia the oxygen accumulator. Chlorate candles were iacorporated iato backpacks designed for use ia the ApoUo moon missions (14). 

Fig. 10. The 800 x 800 pixel scientific CCD specifically designed for the Galileo mission to Jupiter. The devices are shown in wafer form after initial...

Bury (1974 1975 1978 1999) introduces the concept of duty cycles to static design in a different approach. The duty cycle or mission length of a design is equivalent to the number of load applications, however, it is only the maximum value which is of design significance. If the load, L, is a random variable then so is its maximum value, L, and the PDFs of each are related. It can be shown that the CDF, F L), of the maximum among independent observations on L is ... 

In the organizational sense, a function is a special or major activity (often unique in the organization) which is needed in order for the organization to fulfill its purpose and mission. Examples of functions are design, procurement, personnel, manufacture, marketing, maintenance, etc. 

Weight savings can also mean the difference between whether the structure we design can perform its mission or not. The current Space Shuttle payload is limited to 60,000 lb (27,200 kg). If we have an object that we wish to carry up into space that weighs 65,000 lb (29,500 kg), then we are out of luck. That object does not satisfy the Shuttle s weight limit. We must wait for a new-generation Space Shuttle, or sufficient weight in the object to be carried must be saved to fit within the current Space Shuttle limitations. 

Mission statements and charters are often most useful when expressed in terms of job functions rather than of individuals, especially for long-term initiatives during which there may be turnover in the composition of the designated task team. 

Following are two versions of a PSM team s mission statement. The first Is a draft prepared in advance of such a team s first meeting the second reflects group consensus and is designed for dissemination to company employees. 

The Task Force s mission is to design a state-of-the-art process safety management system that will support all of Company X s varied business operations, and to install it at a pilot site to be determined. The team will maintain ongoing communication with Division C s Facility Managers Council, which has accepted responsibility for focusing on the division s process safety management systems. 

Clearcut Mission. As with other team structures discussed in this volume, the design team needs a clearly articulated understanding of its mission, responsibilities, and limits. 

Dry Cells Chemical. -Simplicity. -Low output -Short life-span -Bulk -Current deterioration. In use for short duration space missions. Various designs provide different life-span and output. 

Fuel Cells Chemical. -High output -Stable current -Water supply as a sub-product. -Complex design -Bulk -Life-span is limited by onboard fuel supply. Used in some piloted spacecraft for short duration missions. 

The mission originally assigned to the Ordnance Department was to design, develop, procure, store, maintain, and supply to the Army such equipment and supplies as are assigned to the Ordnance Department for procurement, in such quantities and at such times as are required to meet the requirements of Army supply programs and other directives of higher authority. 

Mission. To perform research, design development, engineering, integrated logistic support, maintenance support, procurement, fabrication, and product assurance of assigned materiel Major Functions. 

Thus, during the Korean conflict, Picatinny reassumed its mission meeting emergencies on time, and the mass production of the ordnance it had designed and developed... 

The most important consideration in the design of an operational ignition system is the time interval from the initiation of the igniter to the generation of the design thrust level in the motor. As indicated previously, the mission... 

The discussion of the important design considerations of solid-propellant motors presented in Section I has shown the importance of the steady-state burning rate of the propellant. The particular mission for a rocket motor to... 

The prediction of burning-rate characteristics, on the other hand, has not been possible. This has caused rocket designers to adopt a trial-and-error approach to the development of specific propellants to meet specific mission requirements. In an effort to reduce the large development effort required for each new propulsion system, considerable basic research effort has been directed toward the definition and quantitative characterization of propellant combustion mechanisms. The ultimate objective of this effort is to provide methods for predicting the burning-rate characteristics of particular propellant formulations. 

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