Search Results

To sustain the extra-vehicular activity (EVA) rate required to assemble and maintain the International Space Station (ISS), we must enhance our ability to plan, train for, and execute EVAs. An underlying analysis capability must be in place to ensure EVA access to all external worksites either as a starting point for ground training, to generate information needed for on-orbit training, or to react quickly to develop contingency EVA plans, techniques, and procedures. This paper describes a potential flight experiment for application of custom human modeling analysis to plan and train for EVAs to enhance space station functionality and usability through assembly and operation.

The successes of the long-duration MDA/NASA test programs for advanced life-support systems conducted prior to 1971 were highly dependent on the selection and training of both the test crews that remained inside the test chamber throughout the test periods and the outside operating staff. The operating staff was responsible for overall test performance, crew safety monitoring, operation and maintenance of the test facilities, and collection and maintenance of data. A selection, training, and certification program was developed and performed to ensure operating staff members had the correct technical skills and could work effectively together with the inside crew. A training program was designed to ensure that each selected operating staff member was capable of performing all assigned functions and was sufficiently cross-trained to serve at other positions on a contingency basis, if needed.

Tactical aircraft have tire lives as low as 3-5 landings per tire causing excessive support costs. The goal of the Improved Tire Life (ITL) program was to begin developing technology to double aircraft tire life, particularly for tactical aircraft. ITL examined not only the tire, but also aircraft/landing gear design, aircraft operations, and the operational environment. ITL had three main thrusts which were successfully accomplished: 1) development of an analytical tire wear model, 2) initiation of technology development to increase tire life, and 3) exploration of new and unique testing methods for tire wear. This paper reports the work performed and the results of the USAF sponsored ITL program.

A CELSS has been defined based on current or near-term technology. The CELSS was sized to support the metabolic load of four people on the Moon for ten years. A metabolic load of 14 MJ/person/day is assumed, including an average of 2.6 hr of EVA/person/day. Close to 100% closure of water, and oxygen, and 85% closure of the food loop is assumed. With 15% of the calories supplied from Earth, this should provide adequate dietary variety for the crew along with vitamin and mineral requirements. Other supply and waste removal requirements are addressed. The basic shell used is a Space Station Freedom 7.3 m (24 ft) module. This is assumed to be buried in regolith to provide protection from radiation, meteoroids, and thermal extremes. A solar dynamic power system is assumed, with a design life of 10 years delivering power at 368 kWh/kg. Initial estimates of size are that 73 m2 of plant growth area are required, giving a plant growth volume of about 73 m3.

The selection of a life support system for a lunar base depends on many interrelated factors, both programmatic and technical. Many factors are identifiable through the application of a systems engineering approach to the lunar base design, in which base and mission requirements are determined. In addition, there is a range of evolving technology options whose cost and maturity affect their potential for inclusion in base designs. Results of ongoing lunar base design are presented with emphasis on the selection of promising approaches for advanced life support systems that decrease overall cost for a single, permanently inhabited lunar base. We identify critical technology areas that inhibit the selection of closed life support systems and propose alternative basing scenarios to alleviate development and operational costs. In particular, we quantify the cost savings associated with establishing a base at a lunar pole in a region of permanent sunlight.

The size and complexity of Space Station has driven the need for an accurate, reliable analytical tool to assess the extravehicular activity (EVA) crew interfaces at the worksite. On previous spacecraft, each worksite was developed and validated through Neutral Buoyancy underwater testing by the crew using mockups. For spacecraft requiring a significant amount of EVA over large areas, like Space Station, the cost of conducting underwater tests for each of the many hundred worksites becomes prohibitive. Therefore, limited testing must be augmented by accurate graphical analysis. The Unigraphics II, which is the Computer Aided Design (CAD) system for the International Space Station Alpha (ISSA) Product Group 1 design, was selected and developed. It has a major advantage of easy and rapid access to the accurate and updated Space Station design. The design can be rapidly obtained electronically from layouts, detail drawings, assembly drawings or the Electronic Development Fixture (EDF).

The objective of this paper is to present results of MDA's payload vibration isolation system research and development program. A unique isolation system with passive or active capabilities designed to provide isolation down to 10-6 g was developed and tested in our 1-g testbed under simulated microgravity conditions. Fluid and electrical umbilicals are also included in the system. The established isolation system performance requirements were met and the testbed data were used to refine our analytical models for predicting flight performance. Simulations using an updated Space Station configuration showed that the payload microgravity requirement can be met by upgrading the hardware from laboratory to flight tolerances and improving the control system design. The next step is to flight test the systems verified in 1 g on the STS/SPACEHAB using a middeck locker size development unit.

This paper presents an overview of the design and operation of the internal thermal control system (ITCS) developed for Space Station Freedom by the NASA-Johnson Space Center and McDonnell Douglas Aerospace to provide cooling for the resource nodes, airlock, and pressurized logistics modules. The ITCS collects, transports, and rejects waste heat from these modules by a dual-loop, single-phase water cooling system. ITCS performance, cooling, and flow rate requirements are presented. An ITCS fluid schematic is shown and an overview of the current baseline system design and its operation is presented. Assembly sequence of the ITCS is explained as its configuration develops from Man Tended Capability (MTC), for which node 2 alone is cooled, to Permanently Manned Capability (PMC) where the airlock, a pressurized logistics module, and node 1 are cooled, in addition to node 2.

This paper presents the integrated approach toward failure detection, isolation, and recovery/reconfiguration to be used for the Space Station Freedom External Active Thermal Control System (EATCS). The on-board and on-ground diagnostic capabilities of the EATCS are discussed. Time and safety critical failures, as well as noncritical failures, and the detection coverage for each provided by existing capabilities are reviewed. The allocation of responsibility between onboard software and ground-based systems, to be shown during ground testing at the Johnson Space Center, is described. Failure isolation capabilities allocated to the ground include some functionality originally found on orbit but moved to the ground to reduce on-board resource requirements. Complex failures requiring the analysis of multiple external variables, such as environmental conditions, heat loads, or station attitude, are also allocated to ground personnel.