5. Intact Abort which indicates safe return of the Shuttle crew and passengers also implies the safe return of the payload. This in turn can have the impact of reducing the requirement for spare or "backup" spacecraft.

In Fiscal Year 1974. Payload Analysis and Requirements studies will place emphasis on providing data and information for use in the design of the Space Shuttle and in the definition of the Sortie Lab and the Space Tug. Corollary studies will supply the inputs necessary to stimulate payload designers to formulate concepts for effective utilization of the Shuttle, Sortie Lab and Space Tug. Specific study and analyses efforts in Payload Analysis and Requirements to be funded in Fiscal Year 1974 include:

1. The development of low cost payload concepts.

2. The development of payload design criteria and requirements for the Shuttle. 3. The effect of payload retrieval, repair and refurbishment capabilities on the design and development of payloads.

4. The establishment of payload requirements data.

MISSION ANALYSIS AND REQUIREMENTS

Mission Analysis and Requirements activities include the following: 1. Development and maintenance of the NASA mission model.

2. Payload capture analysis/economic assessment.

3. Interface requirements and trades.

4. Operation approaches.

The NASA Mission Model

The NASA payload program, usually referred to as the mission model, is a document defining NASA missions for the Shuttle system projected through 1990. The mission model is a fundamental reference document for NASA payload planning activities and for the formulation of requirements for mission supporting systems. Based on current assessment of user needs, both internal and external to NASA (i.e., DOD, other Federal agencies, industrial organizations, and foreign governments), present planning for Shuttle missions envisions a payload program involving 50-60 flights per year over a 10-year period from 1980 to 1990. However, the Mission Model requires frequent redefinition and updating to reflect changes in agency goals, resources availability and modifications of user requirements.

Payload Capture Analysis/Mission Assessment

This activity involves the assignment of payloads to launch systems the Space Shuttle and expendable launch vehicles where required-in order to develop launch system traffic, flight and ground system requirements, and comparative data on alternate concepts of payload design and mission accomplishment. Payloads, selected from the NASA Mission Model, are grouped into compatible sets and given mission assignments. These missions are then analyzed for overall sys tem requirements.

Various payload low cost and reusable design concepts are evaluated in the capture analysis. The studies and analyses underway now will provide the background, alternatives and ideas leading to the optimum payload design selections which will achieve the lowest total payload program costs.

The final results of the payloads capture analysis describe the traffic and cost profiles associated with the mission model. Detailed information is also developed on the payloads themselves and these data are also useful in outlining a program of funded studies for payload definition by the various discipline of fices. Although the particular payloads and mission assignments which are analyzed in this activity cannot be considered as firm planning, they are recog nized to be representative of those which will be flown. Their analysis and pe riodic updating, therefore, permits the formulation of systems and operating requirements, and provides a mechanism for simulation of the space transportation operational phase.

Interface Requirements and Trades

Payload interface requirements and trades studies have been initiated in fiscal year 1973 and will continue in fiscal year 1974. This information is needed to provide data for use in the final design of the Space Shuttle and in the definition

of the Sortie Lab and the Space Tug. The major effort in this area will focus on hardening interface requirements. Cost trade analyses will also be supported to determine the most economical payload design specifications. Transportation cost will continue to be a significant factor in this analysis. The opportunity to reduce cost by relaxation of design constraints and by combining several payloads in a single launch will be given appropriate consideration.

Operations Approaches

When compared to current practices, Space Shuttle flight operations will open up many new advantages which will revolutionize our whole approach to payload operations in space (figure 170). Flight opportunities will no longer be limited to a single flight. Multiple routine flights will be programed where fabrication and qualification costs or scientific output justify repeated operations. Interface and checkout procedures in flight will be simplified. State-of-the-art type of hardware will offer less of a penalty because of reduced design and weight constraints. Management operations will be simplified, thus reducing organizational interactions and documentation requirements. Launch and recovery flexibility and the benign environment afforded by the Shuttle will enable the principal investigator to use "off-the-shelf" type instrumentation where possible in his work, thus reducing instrument development and test cycles.

One area receiving special attention is evaluation of launch site requirements and operating procedures for the Shuttle. Procedures involving a broad range of prior activities are being examined in order to identify those activities which will be required for Shuttle operations and those which should undergo major changes. The diverse background which serves as the basis for this examination and analysis is illustrated in figure 171 (see p. 444). In order to achieve reductions in costs-functions, facilities, personnel and hardware must be reduced or eliminated. In the case of ground operations, studies are underway which will help formulate concepts and procedures to achieve rapid turn-around to reduce leadtime for payload development, reduce payload checkout requirements and lower support and maintenance requirements for the payloads at the launch site.

SPACE SHUTTLE PAYLOAD OPERATIONS ADVANTAGES

MULTIPLE FLIGHT OPPORTUNITIES

SIMPLIFIED INTERFACE AND CHECKOUT PROCEDURES

RECOVERY OF SELECTED PAYLOADS

• SHORT LEAD TIME STATE-OF-THE-ART HARDWARE FOR PAYLOADS

SIMPLIFIED MANAGEMENT OPERATIONS

QUICK DATA COLLECTION FROM SPACE

ELIMINATION OF COSTLY PAYLOAD AND INSTRUMENT DEVELOPMENT AND TEST CYCLES

ON ORBIT RESUPPLY OF PAYLOADS

DIRECT PARTICIPATION OF NON-ASTRONAUT PERSONNEL IN PAYLOAD OPERATIONS

In addition, with the shuttle sortie mode of operation, the principal investigator can accompany his instruments in flight, and perform on-orbit investigations in a manner analogous to the practices which are followed in terrestrial laboratories. Such approaches have been adapted economically and effectively to airborne laboratories, such as the Convair 990 shown in figure 172. High altitude astronomy and Earth resources are examples of the types of research being performed. Economical "off-the-shelf" type instruments are utilized. In the past fiscal year, a study was initiated to look at the possibility of using the airborne experiment approach in conducting experiments on the Space Shuttle. This study is called "Airborne Science/Shuttle Experiments Systems Simulation," or "ASSESS" for short. It is recognized, of course, that there will always be significant differences between space research and research conducted in aircraft or on the ground. The use of the Shuttle and the Sortie Lab will, however, permit the elimination of many of the differences which have existed in the past and the impact of those differences which must remain will be reduced. Preliminary results in comparing approaches currently followed in performing experiments in conventionally launched spacecraft and in aircraft indicate that large savings in cost and experiment preparation time can be effected for experiments to be flown on the Space Shuttle in the sortie mode by moving in the direction of the approach which has been used in the aircraft program.

Specific studies and analyses in mission analysis and requirements area planned in fiscal year 1974 include:

1. Updating of the NASA mission model.

2. Continued payload capture analysis and assessment.

3. Studies to devise new ground and flight operational concepts and procedures for Shuttle payloads.

The Space Transportation System introduces new dimensions to the possible modes of operation in space. It also offers the potential of dramatic improvements in the cost-effectiveness of these space operations. This potential will be realized, however, only if the community of users becomes aware of the characteristics of the system and of the opportunities which it can provide. One of the responsibilities of the recently formulated mission and payload integration office is to work with the using community, inform it of the status and progress which is being made on the system, and conduct analyses to assure that the system remains responsive to the users needs.

Inherent in the fulfillment of this responsibility will be activities which convey the nature of the new shuttle-based philosophy for space activities to existing and potential users; relate the potential use of the Shuttle to prospective user needs; improve Shuttle accommodation and capabilities based on user requirements, experience, and ideas; support the study of new uses for the Shuttle; and provide conceptual support and planning to all potential users.

As part of these activities user conferences will be held similar to the symposia held in June 1970 in Paris, France, and in September 1970 at the Ames Research Center.

An initial worshop along these lines was recently held at the Goddard Space Flight Center. The first meeting concentrated on examination of the shuttle sorties mode of flight. It was sponsored by the Office of Space Science and the Office of Applications and supported by the Office of Manned Space Flight. The specific workshop objectives included:

1. Informing potential NASA users of the present Space Shuttle sorties mode characteristics and capabilities.

2. Informing Shuttle developers of user desires and requirements.

3. An initial assessment of the potential role of the sortie mode in each of the several NASA disciplines.

4. The identification of specific Space Shuttle sortie missions with their characteristics and requirements.

5. The identification of the policies and procedures which must be changed or instituted to fully exploit the potential of the Space Shuttle sortie mode.

6. Determining the next series of steps required to plan and implement Space Shuttle sortie mode missions.

To accomplish these objectives, 15 working groups representing the scientific, applications and medical disciplines met for a week to formulate plans in their specific technical areas (figure 173). The workshop agenda was structured to

give the working groups a management overview of the Space Shuttle program, the current status of the Space Shuttle sortie mode planning, and an opportunity to discuss the results of their efforts, both with the people responsible for the Shuttle systems and with the members of the other working groups. The reports of the various working groups are being utilized to update the NASA mission model and to produce a set of accommodation requirements which should be included in the Shuttle design. The work of these groups is being expanded to include a representative input from organizations outside of NASA, both in this country and abroad.

SUMMARY

The activities just described are aimed toward the development and investiga tion of concepts for the effective and efficient use of the Space Shuttle, the Sortie Lab and the Tug. Through exploratory studies of new approaches to payload design and operational procedures, a basis for significant improvements in the effectiveness of space investigations will be established. Mission analyses will lead to the establishment of system requirements. Finally, the providing of an effective bridge between those who carry the responsibility for system development and those who will be the system users, will assure that the characteristics of the Shuttle, the Sortie Lab and the Tug are fully and effectively utilized dur ing their operational lifetimes.