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At least 127 records · Page 7

Ares Launch Vehicles Lean Practices Case Study

The Ares launch vehicles team, managed by the Ares Projects Office (APO) at NASA Marshall Space Flight Center, has completed the Ares I Crew Launch Vehicle System Requirements Review and System Definition Review and early design work for the Ares V Cargo Launch Vehicle. This paper provides examples of how Lean Manufacturing, Kaizen events, and Six Sigma practices are helping APO deliver a new space transportation capability on time and within budget, while still meeting stringent technical requirements. For example, Lean philosophies have been applied to numerous process definition efforts and existing process improvement activities, including the Ares I-X test flight Certificate of Flight Readiness (CoFR) process, risk management process, and review board organization and processes. Ares executives learned Lean practices firsthand, making the team "smart buyers" during proposal reviews and instilling the team with a sense of what is meant by "value-added" activities. Since the goal of the APO is to field launch vehicles at a reasonable cost and on an ambitious schedule, adopting Lean philosophies and practices will be crucial to the Ares Project's long-term SUCCESS.

Doreswamy, Rajiv↗

An Examination of Launch Vehicle Loads Reanalysis Techniques

The typical approach to calculating dynamic launch loads in aerospace applications is coupled loads analysis (CLA). A component mode model of the launch vehicle is coupled with a component mode model of a payload, system modes are calculated, forcing functions are applied, and the dynamic responses are computed. This approach requires the explicit knowledge of the component models for the launch vehicle and payload, as well as the forcing functions. In many situations, the launch vehicle and forcing functions do not change from one analysis to the next only the payload is different. For this type of application, a method called reanalysis was developed to compute the response of a modified payload on the same launch vehicle. If the launch forcing functions are also the same, the approach eliminates the need for the launch vehicle model and the forcing functions and dramatically reduces the computation time. This work investigates the application and accuracy of three previously developed reanalysis methods using a typical launch vehicle and two different payloads. All three methods are based on knowledge of system modes from the original CLA, and Hurty/Craig-Bampton (HCB) models of the original and new payloads. The first method was developed at JPL (Jet Propulsion Lab) and is often referred to as substitution. It is a frequency-domain method, which requires transformation of time signals to and from the frequency domain. The other two methods are time-domain methods that more closely mimic the CLA process. The three methods were applied to two simple examples and a more complex one. The results indicate that the time-domain methods are considerably more robust with respect to modal truncation and other numerical errors than the frequency-domain JPL method.

Reanalysis↗

Launch Vehicle Debris Models and Crew Vehicle Ascent Abort Risk

For manned space launch systems, a reliable abort system is required to reduce the risks associated with a launch vehicle failure during ascent. Understanding the risks associated with failure environments can be achieved through the use of physics-based models of these environments. Debris fields due to destruction of the launch vehicle is one such environment. To better analyze the risk posed by debris, a physics-based model for generating launch vehicle debris catalogs has been developed. The model predicts the mass distribution of the debris field based on formulae developed from analysis of explosions. Imparted velocity distributions are computed using a shock-physics code to model the explosions within the launch vehicle. A comparison of the debris catalog with an existing catalog for the Shuttle external tank show good comparison in the debris characteristics and the predicted debris strike probability. The model is used to analyze the effects of number of debris pieces and velocity distributions on the strike probability and risk.

Gee, Ken↗

United States launch vehicle systems

United States policy for national space launch capability provides for a balanced mix of launches, utilizing the Space Shuttle and Expendable Launch Vehicles (ELVs). The current mixed fleet includes the Space Shuttle and four expendable launch vehicles - Titan, Atlas, Delta, and Scout. New small class launch vehicles, including Pegasus, are in development. In addition, studies are underway to assure that the United States has cost-effective, reliable access to space, heavy-lift launch capability, and a new manned spacecraft after the current Space Shuttle reaches the end of its operational life. This paper highlights the current capabilities of the mixed fleet and summarizes the plans for new or modified United States launch vehicles through the first decade of the next century.

Krause, Robert B.↗

Flight and Integrated Vehicle Testing: Laying the Groundwork for the Next Generation of Space Exploration Launch Vehicles

Integrated vehicle testing will be critical to ensuring proper vehicle integration of the Ares I crew launch vehicle and Ares V cargo launch vehicle. The Ares Projects, based at Marshall Space Flight Center in Alabama, created the Flight and Integrated Test Office (FITO) as a separate team to ensure that testing is an integral part of the vehicle development process. As its name indicates, FITO is responsible for managing flight testing for the Ares vehicles. FITO personnel are well on the way toward assembling and flying the first flight test vehicle of Ares I, th Ares I-X. This suborbital development flight will evaluate the performance of Ares I from liftoff to first stage separation, testing flight control algorithms, vehicle roll control, separation and recovery systems, and ground operations. Ares I-X is now scheduled to fly in summer 2009. The follow-on flight, Ares I-Y, will test a full five-segment first stage booster and will include cryogenic propellants in the upper stage, an upper stage engine simulator, and an active launch abort system. The following flight, Orion 1, will be the first flight of an active upper stage and upper stage engine, as well as the first uncrewed flight of an Orion spacecraft into orbit. The Ares Projects are using an incremental buildup of flight capabilities prior to the first operational crewed flight of Ares I and the Orion crew exploration vehicle in 2015. In addition to flight testing, the FITO team will be responsible for conducting hardware, software, and ground vibration tests of the integrated launch vehicle. These efforts will include verifying hardware, software, and grou handling interfaces. Through flight and integrated testing, the Ares Projects will identify and mitigate risks early the United States prepares to take its next giant leaps to the Moon and beyond.

Taylor, Jim↗

Flight and Integrated Vehicle Testing: Laying the Groundwork for the Next Generation of Space Exploration Launch Vehicles

Integrated vehicle testing will be critical to ensuring proper vehicle integration of the Ares I crew launch vehicle and Ares V cargo launch vehicle. The Ares Projects, based at Marshall Space Flight Center in Alabama, created the Flight and Integrated Test Office (FITO) as a separate team to ensure that testing is an integral part of the vehicle development process. As its name indicates, FITO is responsible for managing flight testing for the Ares vehicles. FITO personnel are well on the way toward assembling and flying the first flight test vehicle of Ares I, the Ares I-X. This suborbital development flight will evaluate the performance of Ares I from liftoff to first stage separation, testing flight control algorithms, vehicle roll control, separation and recovery systems, and ground operations. Ares I-X is now scheduled to fly in summer 2009. The follow-on flight, Ares I-Y, will test a full five-segment first stage booster and will include cryogenic propellants in the upper stage, an upper stage engine simulator, and an active launch abort system. The following flight, Orion 1, will be the first flight of an active upper stage and upper stage engine, as well as the first uncrewed flight of an Orion spacecraft into orbit. The Ares Projects are using an incremental buildup of flight capabilities prior to the first operational crewed flight of Ares I and the Orion crew exploration vehicle in 2015. In addition to flight testing, the FITO team will be responsible for conducting hardware, software, and ground vibration tests of the integrated launch vehicle. These efforts will include verifying hardware, software, and ground handling interfaces. Through flight and integrated testing, the Ares Projects will identify and mitigate risks early as the United States prepares to take its next giant leaps to the Moon and beyond.

Taylor, J. L.↗

Launch Vehicle Operations Simulator

The Saturn Launch Vehicle Operations Simulator (LVOS) was developed for NASA at Kennedy Space Center. LVOS simulates the Saturn launch vehicle and its ground support equipment. The simulator was intended primarily to be used as a launch crew trainer but it is also being used for test procedure and software validation. A NASA/contractor team of engineers and programmers implemented the simulator after the Apollo XI lunar landing during the low activity periods between launches.

Blackledge, J. W.↗

Integrated System Test Approaches for the NASA Ares I Crew Launch Vehicle

The Ares I Crew Launch Vehicle (CLV) is being developed by the U.S. National Aeronautics and Space Administration (NASA) to provide crew access to the International Space Station (ISS) and, together with the Ares V Cargo Launch Vehicle (CaLV), serves as one component of a future launch capability for human exploration of the Moon. During the system requirements definition process and early design cycles, NASA defined and began implementing plans for integrated ground and flight testing necessary to achieve the first human launch of Ares I. The individual Ares I flight hardware elements: the first stage five segment booster (FSB), upper stage, and J-2X upper stage engine, will undergo extensive development, qualification, and certification testing prior to flight. Key integrated system tests include the Main Propulsion Test Article (MPTA), acceptance tests of the integrated upper stage and upper stage engine assembly, a full-scale integrated vehicle dynamic test (IVDT), aerodynamic testing to characterize vehicle performance, and integrated testing of the avionics and software components. The Ares I-X development flight test will provide flight data to validate engineering models for aerodynamic performance, stage separation, structural dynamic performance, and control system functionality. The Ares I-Y flight test will validate ascent performance of the first stage, stage separation functionality, and a highaltitude actuation of the launch abort system (LAS) following separation. The Orion-1 flight test will be conducted as a full, un-crewed, operational flight test through the entire ascent flight profile prior to the first crewed launch.

Cockrell, Charles E., Jr.↗

Refinements in the Design of the Ares V Cargo Launch Vehicle for NASA's, Exploration Strategy

NASA is developing a new launch vehicle fleet to fulfill the national goals of replacing the shuttle fleet, completing the International Space Station (ISS), and exploring the Moon on the way to eventual exploration of Mars and beyond. Programmatic and technical decisions during early architecture studies and subsequent design activities were focused on safe, reliable operationally efficient vehicles that could support a sustainable exploration program. A pair of launch vehicles was selected to support those goals the Ares I crew launch vehicle and the Ares V cargo launch vehicle. They will be the first new human-rated launch vehicles developed by NASA in more than 30 years (Figure 1). Ares I will be the first to fly, beginning space station ferry operations no later than 2015. It will be able to carry up to six astronauts to ISS or support up to four astronauts for expeditions to the moon. Ares V is scheduled to be operational in the 2020 timeframe and will provide the propulsion systems and payload to truly extend human exploration beyond low-Earth orbit. (LEO).

Creech, Steve↗

Ensuring Safe Exploration: Ares Launch Vehicle Integrated Vehicle Ground Vibration Testing

Ground vibration testing has been an integral tool for developing new launch vehicles throughout the space age. Several launch vehicles have been lost due to problems that would have been detected by early vibration testing, including Ariane 5, Delta III, and Falcon 1. NASA will leverage experience and testing hardware developed during the Saturn and Shuttle programs to perform ground vibration testing (GVT) on the Ares I crew launch vehicle and Ares V cargo launch vehicle stacks. NASA performed dynamic vehicle testing (DVT) for Saturn and mated vehicle ground vibration testing (MVGVT) for Shuttle at the Dynamic Test Stand (Test Stand 4550) at Marshall Space Flight Center (MSFC) in Huntsville, Alabama, and is now modifying that facility to support Ares I integrated vehicle ground vibration testing (IVGVT) beginning in 2012. The Ares IVGVT schedule shows most of its work being completed between 2010 and 2014. Integrated 2nd Stage Ares IVGVT will begin in 2012 and IVGVT of the entire Ares launch stack will begin in 2013. The IVGVT data is needed for the human-rated Orion launch vehicle's Design Certification Review (DCR) in early 2015. During the Apollo program, GVT detected several serious design concerns, which NASA was able to address before Saturn V flew, eliminating costly failures and potential losses of mission or crew. During the late 1970s, Test Stand 4550 was modified to support the four-body structure of the Space Shuttle. Vibration testing confirmed that the vehicle's mode shapes and frequencies were better than analytical models suggested, however, the testing also identified challenges with the rate gyro assemblies, which could have created flight instability and possibly resulted in loss of the vehicle. Today, NASA has begun modifying Test Stand 4550 to accommodate Ares I, including removing platforms needed for Shuttle testing and upgrading the dynamic test facilities to characterize the mode shapes and resonant frequencies of the vehicle. The IVGVT team expects to collect important information about the new launch vehicles, greatly increasing astronaut safety as NASA prepares to explore the Moon and beyond.

Tuma, M. L.↗

Atomic hydrogen as a launch vehicle propellant

An analysis of several atomic hydrogen launch vehicles was conducted. A discussion of the facilities and the technologies that would be needed for these vehicles is also presented. The Gross Liftoff Weights (GLOW) for two systems were estimated; their specific impulses (I sub sp) were 750 and 1500 lb(sub f)/s/lb(sub m). The atomic hydrogen launch vehicles were also compared to the currently planned Advanced Launch System design concepts. Very significant GLOW reductions of 52 to 58 percent are possible over the Advanced Launch System designs. Applying atomic hydrogen propellants to upper stages was also considered. Very high I(sub sp) (greater than 750 lb(sub f)/s/lb(sub m)) is needed to enable a mass savings over advanced oxygen/hydrogen propulsion. Associated with the potential benefits of high I(sub sp) atomic hydrogen are several challenging problems. Very high magnetic fields are required to maintain the atomic hydrogen in a solid hydrogen matrix. The magnetic field strength was estimated to be 30 kilogauss (3 Tesla). Also the storage temperature of the propellant is 4 K. This very low temperature will require a large refrigeration facility for the launch vehicle. The design considerations for a very high recombination rate for the propellant are also discussed. A recombination rate of 210 cm/s is predicted for atomic hydrogen. This high recombination rate can produce very high acceleration for the launch vehicle. Unique insulation or segmentation to inhibit the propellant may be needed to reduce its recombination rate.

Palaszewski, Bryan A.↗