SCIENTIFIC AND TECHNICAL AEROSPACE REPORTS

A Biweekly Publication of the National Aeronautics and Space Administration
VOLUME 44, ISSUE 14 - JULY 18, 2006

18 SPACECRAFT DESIGN, TESTING AND PERFORMANCE
Includes satellites; space platforms; space stations; spacecraft systems and components such as thermal and environmental controls; and spacecraft control and stability characteristics.

For life support systems see 54 Man/System Technology and Life Support.

For related information see also 05 Aircraft Design, Testing and Performance; 39 Structural Mechanics; and 16 Space Transportation and Safety.

20060020240 NASA Johnson Space Center, Houston, TX, USA

Supportability Issues and Approaches for Exploration Missions

Watson, J. K.; Ivins, M. S.; Cunningham, R. A.; [2006]; 1 pp.; In English; 1st Space Exploration Conference, 30 Jan. - 1 Feb. 2005, Orlando, FL, USA Contract(s)/Grant(s): 905-a0-AF; No Copyright; Avail.: Other Sources; Abstract Only

Maintaining and repairing spacecraft systems hardware to achieve required levels of operational availability during long-duration exploration missions will be challenged by limited resupply opportunities, constraints on the mass and volume available for spares and other maintenance-related provisions, and extended communications times. These factors will force the adoption of new approaches to the integrated logistics support of spacecraft systems hardware. For missions beyond the Moon, all spares, equipment, and supplies must either be prepositioned prior to departure from Earth of human crews or carried with the crews. The mass and volume of spares must be minimized by enabling repair at the lowest hardware levels, imposing commonality and standardization across all mission elements at all hardware levels, and providing the capability to fabricate structural and mechanical spares as required. Long round-trip communications times will require increasing levels of autonomy by the crews for most operations including spacecraft maintenance. Effective implementation of these approaches will only be possible when their need is recognized at the earliest stages of the program, when they are incorporated in operational concepts and programmatic requirements, and when diligence is applied in enforcing these requirements throughout system design in an integrated way across all contractors and suppliers. These approaches will be essential for the success of missions to Mars. Although limited duration lunar missions may be successfully accomplished with more traditional approaches to supportability, those missions will offer an opportunity to refine these concepts, associated technologies, and programmatic implementation methodologies so that they can be most effectively applied to later missions. Author

Spacecraft Maintenance; Systems Engineering; Logistics Management; Mars Missions; Fabrication; Refining

20060020708 NASA Langley Research Center, Hampton, VA, USA

Review of Orbiter Flight Boundary Layer Transition Data

Mcginley, Catherine B.; Berry, Scott A.; Kinder, Gerald R.; Barnell, maria; Wang, Kuo C.; Kirk, Benjamin S.; [2006]; 16 pp.; In English; 9th AIAA/ASME Joint Thermophysics and Heat Transfer Conference, 5-8 Jun. 2006, San Francisco, CA, USA; Original contains color and black and white illustrations Contract(s)/Grant(s): 816-06-03-03-08 Report No.(s): AIAA Paper 2006-2921; Copyright; Avail.: CASI: A03, Hardcopy

In support of the Shuttle Return to Flight program, a tool was developed to predict when boundary layer transition would occur on the lower surface of the orbiter during reentry due to the presence of protuberances and cavities in the thermal protection system. This predictive tool was developed based on extensive wind tunnel tests conducted after the loss of the Space Shuttle Columbia.

Recognizing that wind tunnels cannot simulate the exact conditions an orbiter encounters as it re-enters the atmosphere, a preliminary attempt was made to use the documented flight related damage and the orbiter transition times, as deduced from flight instrumentation, to calibrate the predictive tool. After flight STS-114, the Boundary Layer Transition Team decided that a more in-depth analysis of the historical flight data was needed to better determine the root causes of the occasional early transition times of some of the past shuttle flights.

In this paper we discuss our methodology for the analysis, the various sources of shuttle damage information, the analysis of the flight thermocouple data, and how the results compare to the Boundary Layer Transition prediction tool designed for Return to Flight. Author Boundary Layer Transition; Space Shuttles; Protuberances; Predictions; Damage Assessment; Flight Instruments; Thermal Protection 20060020768 NASA Johnson Space Center, Houston, TX, USA Extravehicular Mobility Unit (EMU) / International Space Station (ISS) Coolant Loop Failure and Recovery Lewis, John F.; Cole, Harold; Cronin, Gary; Gazda, Daniel B.; Steele, John; [2006]; 9 pp.; In English; ICES, 16-19 Jul. 2006, Norfolk, VA, USA; Original contains color illustrations Report No.(s): SAE-2006-01-2240; Copyright; Avail.: CASI: A02, Hardcopy

Following the Colombia accident, the Extravehicular Mobility Units (EMU) onboard ISS were unused for several months. Upon startup, the units experienced a failure in the coolant system. This failure resulted in the loss of Extravehicular Activity (EVA) capability from the US segment of ISS. With limited on-orbit evidence, a team of chemists, engineers, metallurgists, and microbiologists were able to identify the cause of the failure and develop recovery hardware and procedures. As a result of this work, the ISS crew regained the capability to perform EVAs from the US segment of the ISS. Author International Space Station; Extravehicular Mobility Units; Cooling Systems; Failure; Losses; Extravehicular Activity 20060021462 NASA Johnson Space Center, Houston, TX, USA International Space Station (ISS) Water Transfer Hardware Logistics Shkedi, Brienne D.; [2006]; 8 pp.; In English; International Conference on Environmental Systems, 17-20 Jul. 2006, Norfolk, VA, USA; Original contains color illustrations Contract(s)/Grant(s): 769-06-01-01-01 Report No.(s): SAE-2006-01-2093; Copyright; Avail.: Other Sources Water transferred from the Space Shuttle to the International Space Station (ISS) is generated as a by-product from the Shuttle fuel cells, and is generally preferred over the Progress which has to launch water from the ground. However, launch mass and volume are still required for the transfer and storage hardware. Some of these up-mass requirements have been reduced since ISS assembly began due to changes in the storage hardware (CWC).

This paper analyzes the launch mass and volume required to transfer water from the Shuttle and analyzes the up-mass savings due to modifications in the CWC. Suggestions for improving the launch mass and volume are also provided. Author

International Space Station; Logistics; Water; By-Products; Fuel Cells

Source: NASA