SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The scheduling algorithm for mission planning and logistics evaluation (SAMPLE) is presented. Two major subsystems are included: The mission payloads program; and the set covering program. Formats and parameter definitions for the payload data set (payload model), feasible combination file, and traffic model are documented.
The functional specifications, functional design and flow, and the program logic of the GREEDY computer program are described. The GREEDY program is a submodule of the Scheduling Algorithm for Mission Planning and Logistics Evaluation (SAMPLE) program and has been designed as a continuation of the shuttle Mission Payloads (MPLS) program. The MPLS uses input payload data to form a set of feasible payload combinations; from these, GREEDY selects a subset of combinations (a traffic model) so all payloads can be included without redundancy. The program also provides the user a tutorial option so that he can choose an alternate traffic model in case a particular traffic model is unacceptable.
The paper discusses the experiences of a group of engineers and logisticians at John F. Kennedy Space center in the design, construction and activation of a consolidated logistics facility for support of Space Transportation System ground operations and maintenance. The planning, methodology and processes are covered, with emphasis placed on unique aspects and lessons learned. The project utilized a progressive design, baseline and build concept for each phase of construction, with the Government exercising funding and configuration oversight.
The logistics of OMV free-flyer servicing are examined, with emphasis on integrating the OMV operations into the overall STS-Space Station system. The depletion rate of consumables and lifetimes of free-flyer components are known quantities, which permits definition of a predictable maintenance schedule. Servicing with an OMV will depend on the position and capabilities of the OMV, Shuttle and Station when free-flyer maintenance is needed. Optimized orbital servicing of free-flyers will involve coordination of and resolution of schedule conflicts among STS, the OMV and the Station. The scheduled availability of any of the three components will be predicted in terms of probabilities that any one of the components will not be needed for another mission while performing the mission they are on.
Supportability issues for the 1.8 meter centrifuge in the Life Science Research Facility are addressed. The analysis focuses on reliability and maintainability and the potential impact on supportability and affordability. Standard logistics engineering methodologies that will be applied to all Office of Space Science and Applications' (OSSA) payload programs are outlined. These methodologies are applied to the 1.8 meter centrifuge.
NASA's Space Station Maintenance Planning and Analysis (MP&A) Study is a step in the overall Space Station Program to define optimum approaches for on-orbit maintenance planning and logistics support. The approach used in the MP&A study and the analysis process used are presented. Emphasis is on maintenance activities and processes that can be accomplished on orbit within the known design and support constraints of the Space Station. From these analyses, recommendations for maintainability/maintenance requirements are established. The ultimate goal of the study is to reduce on-orbit maintenance requirements to a practical and safe minimum, thereby conserving crew time for productive endeavors. The reliability, availability, and maintainability (RAM) and operations performance evaluation models used were assembled and developed as part of the MP&A study and are described. A representative space station system design is presented to illustrate the analysis process.
The Orbit Transfer Vehicle (OTV), representing the next generation of upper stages, has recently been studied in a Phase A concept definition study managed by NASA's Marshall Space Flight Center. The vehicle has been previously defined as strictly an orbit-to-orbit type transfer device. Recently its application to the task of lunar surface logistics was investigated. Transfer options to the surface were considered which included direct transfer, and transfer via lunar orbit as well as the L1 libration point. The subsystem modifications required to enable lunar landings were established for the following elements: aerobrake, main propulsion system, landing legs, primary structure, and avionics. It is concluded that the majority of the basic systems required for efficient transfer to the lunar surface are already contained in the OTV.
The NASA Shuttle-C unmanned launch vehicle and the Shuttle/Space Station-based Orbital Maneuver Vehicle will be used in support of NASA Space Station assembly and logistics operations, as well as for the orbital servicing of the Hubble Space Telescope (1989), the Advanced X-ray Astrophysical Facility (1996), and the Space Infrared Telescope Facility (1998). Accounts are presently given of these observatories' configurations, capabilities, and mission scenarios, as well as of the Shuttle-C-based Space Station assembly sequence.
The logistic support of space facilities is described, with special attention given to the problem of sizing the inventory of ready spares kept at the space facility. Where possible, data from the Space Shuttle Orbiter is extrapolated to provide numerical estimates for space facilities. Attention is also given to repair effort estimation and long duration missions.
Logistic difficulties associated with the Space Station Freedom are discussed. Proposed ground and on-orbit operations and procedures for supplying the Station are described. The transfer operations of supplies to the modules, the use of expendable launch vehicles for supplying the Station, and the use of EVA suits for assembling and servicing are considered. Ground support activities for resupplying and maintaining the spacecraft are examined.
An interactive computer scheduling tool, the MFIVE Space Station Crew Activity Scheduler and Stowage Logistics Clerk, is described. The MFIVE employs the intelligent perturbation method, which was developed to schedule complex time and resource constrained problems. This algorithm was used to minimize the completion time of sample scheduling problems and solutions were derived which averaged within 7 percent of optimum where standard solution techniques gave solutions 23 percent longer than optimum.
The concept of the NASA Shuttle Logistics Depot (NSLD) developed for the Space Shuttle Orbiter Program is described. The function of the NSLD at Cape Canaveral is to perform the acceptance and diagnostic testing of the Shuttle's space-rated line-replaceable units and shop-replaceable units (SRUs). The NSLD includes a comprehensive electronic automatic test station, program development stations, and assorted manufacturing support equipment (including thermal and vibration test equipment, special test equipment, and a card SRU test system). The depot activities also include the establishment of the functions for manufacturing of mechanical parts, soldering, welding, painting, clean room operation, procurement, and subcontract management.
The implications of logistics and operations on the manual control of spacecraft docking are discussed. The results of simulation studies to investigate fuel and time cost tradeoffs are reviewed and discussed. Comparisons of acceleration control and pulse control are presented to evaluate the effects of astronauts being instructed to use pulse mode for fuel conservation. The applications of the findings to moon and Mars missions are addressed.
A significant percentage of the maintenance tasks for Space Station Freedom are anticipated to be conducted in the unpressurized environment. The maintenance concept for this environment essentially involves the removal and replacement of relatively large orbital replacement units (ORUs). Major constraints will be the on-orbit availability of both crew time and spare ORUs. The challenge presented to the program will be the performance of unpressurized cargo resupply that provides maximum cargo-carrying capability (mass and volume) and flexibility (type and quantity), while minimizing the impact to maintenance task times. The design of the logistics carriers is a critical component for successful resupply and maintenance operations, and to the success of Space Station Freedom.
The analysis for determining the optimum cylindrical length of the Space Station Freedom (SSF) Pressurized Logistics Module, whose task is to transport the SSF pressurized cargo via the NSTS Shuttle Orbiter, is described. The major factors considered include the NSTS net launch lift capability, the pressurized cargo requirements, and the mass properties of the module structures, mechanisms, and subsystems.
Viewgraphs and discussion on data management standards in computer-aided acquisition and logistic support (CALS) are presented. CALS is intended to reduce cost, increase quality, and improve timeliness of weapon system acquisition and support by greatly improving the flow of technical information. The phase 2 standards, industrial environment, are discussed. The information resource dictionary system (IRDS) is described.
The day will come when the United States will want to return to the Earth's Moon. When that occurs, NASA may look to the Apollo program for technical and inspirational guidance. The Apollo program, however, was designed to be an end to itself--the landing of a man on the Moon and his return safely within the decade of the 1960's. When that was accomplished, the program folded because it was not self-sustaining. The next time we return to the Moon, we should base our planning on a program that is designed to be a sustained effort for an indefinite period. It is the thrust of this report that the South Pole Station of the National Science Foundation can be used to develop analogs for the construction, funding, and logistical support of a lunar base. Other analogs include transportation and national efforts versus international cooperation. A recommended lunar base using the South Pole Station as inspiration is provided, as well as details concerning economical construction of the base over a 22-year period.
The primary goal of this project was to develop a tailored and effective approach to the design and evaluation of the human-computer interface (HCI) to the Maintenance, Inventory and Logistics Planning (MILP) System in support of the Mission Operations Directorate (MOD). An additional task that was undertaken was to assist in the review of Ground Displays for Space Station Freedom (SSF) by attending the Ground Displays Interface Group (GDIG), and commenting on the preliminary design for these displays. Based upon data gathered over the 10 week period, this project has hypothesized that the proper HCI concept for navigating through maintenance databases for large space vehicles is one based upon a spatial, direct manipulation approach. This dialogue style can be then coupled with a traditional text-based DBMS, after the user has determined the general nature and location of the information needed. This conclusion is in contrast with the currently planned HCI for MILP which uses a traditional form-fill-in dialogue style for all data access and retrieval. In order to resolve this difference in HCI and dialogue styles, it is recommended that comparative evaluation be performed which combines the use of both subjective and objective metrics to determine the optimal (performance-wise) and preferred approach for end users. The proposed plan has been outlined in the previous paragraphs and is available in its entirety in the Technical Report associated with this project. Further, it is suggested that several of the more useful features of the Maintenance Operations Management System (MOMS), especially those developed by the end-users, be incorporated into MILP to save development time and money.