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NASA NTRS2012

Lessons Learned for Improving Spacecraft Ground Operations

NASA has a unique history in processing the Space Shuttle fleet for launches. Some of this experience has been captured in the NASA Lessons Learned Information System (LLIS). This tool provides a convenient way for design engineers to review lessons from the past to prevent problems from reoccurring and incorporate positive lessons in new designs. At the Kennedy Space Center, the LLIS is being used to design ground support equipment for the next generation of launch and crewed vehicles. This paper describes the LLIS process and offers some examples.

Bell, Michael A.↗

NASA NTRSDate not supplied

Human-Autonomy Teaming Research in Support of m:N Operations

Since 2019, the NASA and industry partners have been involved in research focused on a novel paradigm for operations of remotely piloted aircraft. This paradigm involves multiple people sharing a fleet of multiple vehicles between them. Referred to as m:N (pronounced “em-to-en”), this configuration describes a ratio where m is the number of operators and N is the number of vehicles. Through force and asset multiplication, the m:N concept seeks to enable a scalable and resilient operation of remotely crewed vehicles. The primary means of obtaining such a robust operation is through allowing a flexible crew of variable size to dynamically attend to the needs of assets in while performing real-time operator workload management. It is in that sense that assets are shared between operators: as needed (such as in events of elevated workload) an operator in an m:N context can “handoff” the responsibility for some amount of assets, nh < N, to be absorbed by the m – 1 crew members on staff. At some time later, these nh assets could be returned to their original owner or they may be further distributed to other crew if called for by the mission. During this panel, I will elaborate on the research activity undertaken by the Human-Autonomy Teaming (HAT) Laboratory at NASA Ames Research Center over the previous three years. The studies conducted by the HAT Lab range from interviews with subject matter experts, a cognitive walkthrough, a task analysis, and two simulation experiments to-date. During experimentation, pilots made use of an advanced Ground Control Station developed by the HAT Lab and industry partners to simulate m:N operations in two large, metropolitan areas of Southern California: Los Angeles and San Diego. Further experimentation planned over the next few years. Results from our research to-date indicates that pilots of a moderately sized fleet of about a dozen remotely crewed aircraft adequately maintained safety performance and situation awareness of their aircraft, even when presented with unexpected situations of heightened workload.

multi-vehicle control↗

NASA NTRS1997

Light Absorption of Stratospheric Aerosols: Long-Term Trend and Contribution by Aircraft

Measurements of aerosol light-absorption coefficients are useful for studies of radiative transfer and heating rates. Ogren appears to have published the first light- absorption coefficients in the stratosphere in 1981, followed by Clarke in 1983 and Pueschel in 1992. Because most stratospheric soot appears to be due to aircraft operations, application of an aircraft soot aerosol emission index to projected fuel consumption suggests a threefold increase of soot loading and light absorption by 2025. Together, those four data sets indicate an increase in mid-visible light extinction at a rate of 6 % per year. This trend is similar to the increase per year of sulfuric acid aerosol and of commercial fleet size. The proportionality between stepped-up aircraft operations above the tropopause and increases in stratospheric soot and sulfuric acid aerosol implicate aircraft as a source of stratospheric pollution. Because the strongly light-absorbing soot and the predominantly light-scattering sulfuric acid aerosol increase at similar rates, however, the mid-visible stratospheric aerosol single scatter albedo is expected to remain constant and not approach a critical value of 0.98 at which stratospheric cooling could change to warming.

Pueschel , R. F.↗

NASA NTRS2009

Designing of a Fleet-Leader Program for Carbon Composite Overwrapped Pressure Vessels

Composite Overwrapped Pressure Vessels (COPVs) are often used for storing pressurant gases on board spacecraft when mass saving is a prime requirement. Substantial weight savings can be achieved compared to all metallic pressure vessels. For example, on the space shuttle, replacement of all metallic pressure vessels with Kevlar COPVs resulted in a weight savings of about 30 percent. Mass critical space applications such as the Ares and Orion vehicles are currently being planned to use as many COPVs as possible in place of all-metallic pressure vessels to minimize the overall mass of the vehicle. Due to the fact that overwraps are subjected to sustained loads during long periods of a mission, stress rupture failure is a major concern. It is, therefore, important to ascertain the reliability of these vessels by analysis, since it is practically impossible to show by experimental testing the reliability of flight quality vessels. Also, it is a common practice to set aside flight quality vessels as "fleet leaders" in a test program where these vessels are subjected to slightly accelerated operating conditions so that they lead the actual flight vessels both in time and load. The intention of fleet leaders is to provide advanced warning if there is a serious design flaw in the vessels so that a major disaster in the flight vessels can be averted with advance warning. On the other hand, the accelerating conditions must be not so severe as to be prone to false alarms. The primary focus of the present paper is to provide an analytical basis for designing a viable fleet leader program for carbon COPVs. The analysis is based on a stress rupture behavior model incorporating Weibull statistics and power-law sensitivity of life to fiber stress level.

Murthy, Pappu L.N.↗

NASA NTRS1985

Orbital transfer vehicle concept definition and system analysis study, 1985. Volume 2: OTV concept definition and evaluation. Book 4: Operations

The benefits of the reusable Space Shuttle and the advent of the new Space Station hold promise for increasingly effective utilization of space by the scientific and commercial as well as military communities. A high energy reusable oribital transfer vehicle (OTV) represents an additional capability which also exhibits potential for enhancing space access by allowing more ambitious missions and at the same time reducing launch costs when compared to existing upper stages. This section, Vol. 2: Book 4, covers launch operations and flight operations. The launch operations section covers analyses of ground based and space based vehicles, launch site facilities, logistics requirements, propellant loading, space based maintenance and aft cargo carrier access options. The flight operations sections contain summary descriptions of ground based and space based OTV missions, operations and support requirements, and a discussion of fleet implications.

Mitchell, Jack C.↗

NASA NTRS1993

An artificial intelligence-based structural health monitoring system for aging aircraft

To reduce operating expenses, airlines are now using the existing fleets of commercial aircraft well beyond their originally anticipated service lives. The repair and maintenance of these 'aging aircraft' has therefore become a critical safety issue, both to the airlines and the Federal Aviation Administration. This paper presents the results of an innovative research program to develop a structural monitoring system that will be used to evaluate the integrity of in-service aerospace structural components. Currently in the final phase of its development, this monitoring system will indicate when repair or maintenance of a damaged structural component is necessary.

Grady, Joseph E.↗

NASA NTRS1989

SSME component assembly and life management expert system

The space shuttle utilizes several rocket engine systems, all of which must function with a high degree of reliability for successful mission completion. The space shuttle main engine (SSME) is by far the most complex of the rocket engine systems and is designed to be reusable. The reusability of spacecraft systems introduces many problems related to testing, reliability, and logistics. Components must be assembled from parts inventories in a manner which will most effectively utilize the available parts. Assembly must be scheduled to efficiently utilize available assembly benches while still maintaining flight schedules. Assembled components must be assigned to as many contiguous flights as possible, to minimize component changes. Each component must undergo a rigorous testing program prior to flight. In addition, testing and assembly of flight engines and components must be done in conjunction with the assembly and testing of developmental engines and components. The development, testing, manufacture, and flight assignments of the engine fleet involves the satisfaction of many logistical and operational requirements, subject to many constraints. The purpose of the SSME Component Assembly and Life Management Expert System (CALMES) is to assist the engine assembly and scheduling process, and to insure that these activities utilize available resources as efficiently as possible.

Ali, M.↗

NASA NTRS2008

NASA Ares I Crew Launch Vehicle Upper Stage Overview

By incorporating rigorous engineering practices, innovative manufacturing processes and test techniques, a unique multi-center government/contractor partnership, and a clean-sheet design developed around the primary requirements for the International Space Station (ISS) and Lunar missions, the Upper Stage Element of NASA's Crew Launch Vehicle (CLV), the "Ares I," is a vital part of the Constellation Program's transportation system. Constellation's exploration missions will include Ares I and Ares V launch vehicles required to place crew and cargo in low-Earth orbit (LEO), crew and cargo transportation systems required for human space travel, and transportation systems and scientific equipment required for human exploration of the Moon and Mars. Early Ares I configurations will support ISS re-supply missions. A self-supporting cylindrical structure, the Ares I Upper Stage will be approximately 84' long and 18' in diameter. The Upper Stage Element is being designed for increased supportability and increased reliability to meet human-rating requirements imposed by NASA standards. The design also incorporates state-of-the-art materials, hardware, design, and integrated logistics planning, thus facilitating a supportable, reliable, and operable system. With NASA retiring the Space Shuttle fleet in 2010, the success of the Ares I Project is essential to America's continued leadership in space. The first Ares I test flight, called Ares I-X, is scheduled for 2009. Subsequent test flights will continue thereafter, with the first crewed flight of the Crew Exploration Vehicle (CEV), "Orion," planned for no later than 2015. Crew transportation to the ISS will follow within the same decade, and the first Lunar excursion is scheduled for the 2020 timeframe.

McArthur, J. Craig↗

NASA NTRS2008

NASA Ares I Crew Launch Vehicle Upper Stage Overview

By incorporating rigorous engineering practices, innovative manufacturing processes and test techniques, a unique multi-center government/contractor partnership, and a clean-sheet design developed around the primary requirements for the International Space Station (ISS) and Lunar missions, the Upper Stage Element of NASA's Crew Launch Vehicle (CLV), the "Ares I," is a vital part of the Constellation Program's transportation system. Constellation's exploration missions will include Ares I and Ares V launch vehicles required to place crew and cargo in low-Earth orbit (LEO), crew and cargo transportation systems required for human space travel, and transportation systems and scientific equipment required for human exploration of the Moon and Mars. Early Ares I configurations will support ISS re-supply missions. A self-supporting cylindrical structure, the Ares I Upper Stage will be approximately 84' long and 18' in diameter. The Upper Stage Element is being designed for increased supportability and increased reliability to meet human-rating requirements imposed by NASA standards. The design also incorporates state-of-the-art materials, hardware, design, and integrated logistics planning, thus facilitating a supportable, reliable, and operable system. With NASA retiring the Space Shuttle fleet in 2010, the success of the Ares I Project is essential to America's continued leadership in space. The first Ares I test flight, called Ares 1-X, is scheduled for 2009. Subsequent test flights will continue thereafter, with the first crewed flight of the Crew Exploration Vehicle (CEV), "Orion," planned for no later than 2015. Crew transportation to the ISS will follow within the same decade, and the first Lunar excursion is scheduled for the 2020 timeframe.

Davis, Daniel J.↗

NASA NTRS2012

Evolution of Training in NASA's Mission Operations Directorate

NASA s Mission Operations Directorate provides all the mission planning, training, and operations support for NASA's human spaceflight missions including the International Space Station (ISS) and its fleet of supporting vehicles. MOD also develops and maintains the facilities necessary to conduct training and operations for those missions including the Mission Control Center, Space Station Training Facility, Space Vehicle Mockup Facility, and Neutral Buoyancy Laboratory. MOD's overarching approach to human spaceflight training is to "train like you fly." This approach means not only trying to replicate the operational environment in training but also to approach training with the same mindset as real operations. When in training, this means using the same approach for executing operations, responding to off-nominal situations, and conducting yourself in the operations environment in the same manner as you would for the real vehicle.

Hutt, Jason↗

NASA NTRS1972

STDN network operations procedure for Apollo range instrumentation aircraft, revision 1

The Apollo range instrumentation aircraft (ARIA) fleet which consists of four EC-135N aircraft used for Apollo communication support is discussed. The ARIA aircraft are used to provide coverage of lunar missions, earth orbit missions, command module/service module separation to spacecraft landing, and assist in recovery operations. Descriptions of ARIA aircraft, capabilities, and instrumentation are included.

Vette, A. R.↗

NASA NTRS1992

Space Shuttle Orbiter Fleet Leader Orbital Maneuvering Engine SN 002A injector replacement

During testing of the Fleet Leader Orbital Maneuvering Engine (OME) Serial Number (SN) 002A at the White Sands Test Facility (WSTF) in 1983 the injector was inadvertently damaged. After testing was completed in 1985, there was a concern that the performance of the engine and its response to specific test conditions might not be sufficiently representative of flight engines to provide valid test results. To correct this damage, the engine was returned to the manufacturer to replace the injector. The task assigned was to evaluate the damage and generate a unique process to repair the Fleet Leader OME while providing minimum impact to the overall life condition of the engine. In addition to successfully performing the repair operation, the as received condition of the engine and its components were documented for Fleet Leader reference. The engine is currently at WSTF where it has accumulated 11,341 seconds of firing time to date, 2615 seconds of which have occurred since the engine repair.

Riccio, Joseph R.↗

NASA NTRS2001

Optical Diagnosis of Gas Turbine Combustors Being Conducted

Researchers at the NASA Glenn Research Center, in collaboration with industry, are reducing gas turbine engine emissions by studying visually the air-fuel interactions and combustion processes in combustors. This is especially critical for next generation engines that, in order to be more fuel-efficient, operate at higher temperatures and pressures than the current fleet engines. Optically based experiments were conducted in support of the Ultra-Efficient Engine Technology program in Glenn's unique, world-class, advanced subsonic combustion rig (ASCR) facility. The ASCR can supply air and jet fuel at the flow rates, temperatures, and pressures that simulate the conditions expected in the combustors of high-performance, civilian aircraft engines. In addition, this facility is large enough to support true sectors ("pie" slices of a full annular combustor). Sectors enable one to test true shapes rather than rectangular approximations of the actual hardware. Therefore, there is no compromise to actual engine geometry. A schematic drawing of the sector test stand is shown. The test hardware is mounted just upstream of the instrumentation section. The test stand can accommodate hardware up to 0.76-m diameter by 1.2-m long; thus sectors or small full annular combustors can be examined in this facility. Planar (two-dimensional) imaging using laser-induced fluorescence and Mie scattering, chemiluminescence, and video imagery were obtained for a variety of engine cycle conditions. The hardware tested was a double annular sector (two adjacent fuel injectors aligned radially) representing approximately 15 of a full annular combustor. An example of the two-dimensional data obtained for this configuration is also shown. The fluorescence data show the location of fuel and hydroxyl radical (OH) along the centerline of the fuel injectors. The chemiluminescence data show C2 within the total observable volume. The top row of this figure shows images obtained at an engine low-power condition, and the bottom row shows data from a higher power operating point. The data show distinctly the differences in flame structure between low-power and high-power engine conditions, in both location and amount of species produced (OH, C2) or consumed (fuel). The unique capability of the facility coupled with its optical accessibility helps to eliminate the need for high-pressure performance extrapolations. Tests such as described here have been used successfully to assess the performance of fuel-injection concepts and to modify those designs, if needed.

Hicks, Yolanda R.↗

NASA NTRS1979

Satellite power system: Concept development and evaluation program, reference system report

The Satellite Power System (SPS) Reference System is discussed and the technical and operational information required in support of environmental, socioeconomic, and comparative assessment studies are emphasized. The reference System concept features a gallium-aluminum-arsenide, and silicon solar cell options. Other aspects of an SPS are the construction of bases in space, launch and mission control bases on earth, and fleets of various transportation vehicles to support the construction and maintenance operations of the satellites.

Source record↗

NASA NTRS1972

Applications to aircraft propulsion systems

Estimates of the prospects for quiet airplanes in the future are summarized. The SST using afterburning turbojets and no sound suppression is estimated to produce 129 EPNdb on the sideline. Suppression devices and operating techniques can reduce this noise markedly. The present fleet of 707's and DC-8's produces noises nearly as high as 120 decibels on approach. Combinations of sound absorbing devices and engine modifications are expected to give a noise near 100 decibels. The new advanced technology transports (ATT) are being studied with two noise goals in mind: one is 10 decibels and the other is 20 decibels below the FAR level of 106 on takeoff. New trijets using new quiet engines are expected to meet 90 EPNdb. Future advances in technology are expected to yield another 5 decibels to give noise levels of 80 EPNdb. The STOL airplane has a noise goal of 95 EPNdb along a sideline 500 feet from the runway.

Sanders, N. D.↗

NASA NTRS2010

Sustaining Human Space Flight: From the Present to the Future

This slide presentation reviews some of the efforts to ensure that human space flight continues in NASA. With the aging shuttle orbiter fleet, some actions have been taken to assure safe operations. Some of these are: (1) the formation of a Corrosion Control Review Board (CCRB) that will assess the extent and cause of corrosion to the shuttle, and provide short term and long term corrective actions, among other objectives, (2) a formalization of an aging vehicle assessment (AVA) as part of a certification for the Return-to-Flight, (3) an assessment of the age life of the materials in the space shuttle, and (4) the formation of the Aging Orbiter Working Group (AOWG). There are also slides with information about the International Space Station. There is also information about the need to update the Kennedy Space Center, to sustain a 21st century launch complex and the requirement to further the aim of commercial launch capability.

Russell, Rick↗

NASA NTRS2016

Seat Capacity Selection for an Advanced Short-Haul Aircraft Design

A study was performed to determine the target seat capacity for a proposed advanced short-haul aircraft concept projected to enter the fleet by 2030. This analysis projected the potential demand in the U.S. for a short-haul aircraft using a transportation theory approach, rather than selecting a target seat capacity based on recent industry trends or current market demand. A transportation systems model was used to create a point-to-point network of short-haul trips and then predict the number of annual origin-destination trips on this network. Aircraft of varying seat capacities were used to meet the demand on this network, assuming a single aircraft type for the entire short-haul fleet. For each aircraft size, the ticket revenue and operational costs were used to calculate a total market profitability metric for all feasible flights. The different aircraft sizes were compared, based on this market profitability metric and also the total number of annual round trips and markets served. Sensitivity studies were also performed to determine the effect of changing the aircraft cruise speed and maximum trip length. Using this analysis, the advanced short-haul aircraft design team was able to select a target seat capacity for their design.

Marien, Ty V.↗

NASA NTRS2003

Major Impact of Fleet Renewal Over Airports Located in the Most Important Region of Brazil

The present article discusses and analyses the major impacts of the Brazilian carriers fleet renewal regarding Brazilian airport infrastructure in the most important region of the country, the Southeast (SE). A brief historical overview of the country's airline fleet will be presented, demonstrating the need for its renewal (m fact, Brazilian carriers started a major fleet renewal program m the last five years), while analyzing the periods in which a new breed of aircraft was put into service by the major carriers operating in the SE region. The trend of operating the classic regional jets plus the forthcoming entry into service of the "large regional jets" (LRJ, 70-115 seaters) in several point-to-point routes are presented along with the country's carriers" reality of operating these former aircraft in several high-capacity and medium-range routes. The article will focus on the ability of four of the major Southeast's airports to cope with the fleet modernization, mainly due to the fact that the region studied is the most socioeconomic developed, by far, with the largest demand for air transportation, thus making the impacts much more perceptible for the communities and the airport management involved. With the emergence of these impacts, several new projects and investments are being discussed and pushed forward, despite budgetary constrains being a reality in almost every Brazilian city, even in the SE region. In view of this, the paper presents how the general planning could be carried out in order to adapt the airports' infrastructures in function of the proposed (and in some cases, necessary) fleet renewal. Ultimately, we will present the present picture and two future scenarios m order to determine the level of service in the existent passenger terminal facilities in the wake of the possible operation of several new aircraft. Keywords: Airline fleet planning, Airport planning, Regional development, Regional Jets.

Maters, Rafael Waltz↗