Heavy Lift Launch Vehicle Research Articles

Mechanical challenges in advanced spacecraft development

Space engineering research and developments in mechanics are closely related, and often serve to promote each other. Analysis of the engineering difficulties in advanced spacecraft development and the related mechanical challenges shows that it is very important to overcome the main mechanical problems to enable rapid development of aerospace engineering technologies. When compared with classical spacecraft, a series of new concepts and technologies have been proposed to satisfy the requirements of advanced spacecraft development. These advanced spacecraft, which must overcome the severe effects of the complex launching and space running environments, result in challenging problems of applications in fields such as structural dynamics and computational mechanics. In this paper, a heavy-lift launch vehicle, a large complex spacecraft, a reusable launch vehicle and a hypersonic flight vehicle are introduced as four typical advanced spacecraft to illustrate the reactive relationships between the engineering and mechanical disciplines. Based on descriptions of their technical features, the research difficulties related to these advanced spacecraft are shown. Then, ten typical challenging problems are summarized into research topics in the four classical mechanical subject fields. Two challenging problems of a mechanical nature are shown in each of the three classical mechanics fields of dynamics and control, solid mechanics and aerodynamics. When compared with the engineering problems in a single mechanics discipline, it becomes obvious that research into interdisciplinary mechanical problems is becoming a major trend for advanced spacecraft. To promote concurrent development of advanced spacecraft and the appropriate mechanical disciplines, the following two proposals are made: (1) The close relationships between the engineering requirements and the mechanical disciplines should be given greater attention. The research efforts for advanced spacecraft can be supported by mechanical theory to enable new technological challenges to be overcome. (2) The coalescent development of advanced spacecraft with the disciplines of fundamental mechanics can be guaranteed through joint innovation and development efforts between technical personnel and mechanical researchers, both in China and abroad.

Generatrix shape optimization of stiffened shells for low imperfection sensitivity

According to previous studies, stiffened shells with convex hyperbolic generatrix shape are less sensitive to imperfections. In this study, the effects of generatrix shape on the performances of elastic and plastic buckling in stiffened shells are investigated. Then, a more general description of generatrix shape is proposed, which can simply be expressed as a convex B-spline curve (controlled by four key points). An optimization framework of stiffened shells with a convex B-spline generatrix is established, with optimization objective being measured in terms of nominal collapse load, which can be expressed as a weighted sum of geometrically imperfect shells. The effectiveness of the proposed framework is demonstrated by a detailed comparison of the optimum designs for the B-spline and hyperbolic generatrix shapes. The decrease of imperfection sensitivity allows for a significant weight saving, which is particularly important in the development of future heavy-lift launch vehicles.

A space exploration strategy that promotes international and commercial participation

NASA has created a plan to implement the Flexible Path strategy, which utilizes a heavy lift launch vehicle to deliver crew and cargo to orbit. In this plan, NASA would develop much of the transportation architecture (launch vehicle, crew capsule, and in-space propulsion), leaving the other in-space elements open to commercial and international partnerships. This paper presents a space exploration strategy that reverses that philosophy, where commercial and international launch vehicles provide launch services. Utilizing a propellant depot to aggregate propellant on orbit, smaller launch vehicles are capable of delivering all of the mass necessary for space exploration. This strategy has benefits to the architecture in terms of cost, schedule, and reliability.

A Delphi-Based Framework for systems architecting of in-orbit exploration infrastructure for human exploration beyond Low Earth Orbit

The current debate in the U.S. Human Spaceflight Program focuses on the development of the next generation of man-rated heavy lift launch vehicles. While launch vehicle systems are of critical importance for future exploration, a comprehensive analysis of the entire exploration infrastructure is required to avoid costly pitfalls at early stages of the design process. This paper addresses this need by presenting a Delphi-Based Systems Architecting Framework for integrated architectural analysis of future in-orbit infrastructure for human space exploration beyond Low Earth Orbit. The paper is structured in two parts.The first part consists of an expert elicitation study to identify objectives for the in-space transportation infrastructure. The study was conducted between November 2011 and January 2012 with 15 senior experts involved in human spaceflight in the United States and Europe. The elicitation study included the formation of three expert panels representing exploration, science, and policy stakeholders engaged in a 3-round Delphi study. The rationale behind the Delphi approach, as imported from social science research, is discussed. Finally, a novel version of the Delphi method is presented and applied to technical decision-making and systems architecting in the context of human space exploration.The second part of the paper describes a tradespace exploration study of in-orbit infrastructure coupled with a requirements definition exercise informed by expert elicitation. The uncertainties associated with technical requirements and stakeholder goals are explicitly considered in the analysis. The outcome of the expert elicitation process portrays an integrated view of perceived stakeholder needs within the human spaceflight community. Needs are subsequently converted into requirements and coupled to the system architectures of interest to analyze the correlation between exploration, science, and policy goals. Pareto analysis is used to identify architectures of interest for further consideration by decision-makers.The paper closes with a summary of insights and develops a strategy for evolutionary development of the exploration infrastructure of the incoming decades. The most important result produced by this analysis is the identification of a critical irreducible ambiguity undermining value delivery for the in-space transportation infrastructure of the next three decades: destination choice. Consensus on destination is far from being reached by the community at large, with particular reference to exploration and policy stakeholders. The realization of this ambiguity is a call for NASA to promote an open forum on this topic, and to develop a strong case for policy makers to incentivize investments in the human spaceflight industry in the next decades.

Adaptive fault-tolerant control of heavy lift launch vehicle via differential algebraic observer

A novel adaptive fault-tolerant control scheme in the differential algebraic framework was proposed for attitude control of a heavy lift launch vehicle (HLLV). By using purely mathematical transformations, the decoupled input-output representations of HLLV were derived, rendering three decoupled second-order systems, i.e., pitch, yaw and roll channels. Based on a new type of numerical differentiator, a differential algebraic observer (DAO) was proposed for estimating the system states and the generalized disturbances, including various disturbances and additive fault torques. Driven by DAOs, three improved proportional-integral-differential (PID) controllers with disturbance compensation were designed for pitch, yaw and roll control. All signals in the closed-loop system were guaranteed to be ultimately uniformly bounded by utilization of Lyapunov’s indirect method. The convincing numerical simulations indicate that the proposed control scheme is successful in achieving high performance in the presence of parametric perturbations, external disturbances, noisy corruptions, and actuator faults.

Evolution of the Space Shuttle Primary Avionics Software and Avionics for Shuttle Derived Launch Vehicles

As a result of recommendation from the Augustine Panel, the direction for Human Space Flight has been altered from the original plan referred to as Constellation. NASA s Human Exploration Framework Team (HEFT) proposes the use of a Shuttle Derived Heavy Lift Launch Vehicle (SDLV) and an Orion derived spacecraft (salvaged from Constellation) to a new flexible direction for space exploration. The SDLV must be developed within an environment of a constrained budget and a preferred fast development schedule. Thus, it has been proposed to utilize existing assets from the Shuttle Program to speed development at a lower cost. These existing assets should not only include structures such as external tanks or solid rockets, but also the Flight Software which has traditionally been a long pole in new development efforts. The and for the Space Shuttle was primarily developed in the 70 s and considered state of the art for that time. As one may argue that the existing and flight may be too outdated to the new SDLV effort, this is a fallacy if they can be evolved over time into a avionics platform. The technology may be outdated, but the concepts and flight algorithms are not. The reuse of existing and also allows for the reuse of development, verification, and operations facilities. The keyword is evolve in that these assets can the fast development of such a vehicle, but then be gradually evolved over time towards more modern platforms as budget and schedule permits. The gold of the flight is the control loop algorithms of the vehicle. This is the Guidance, Navigation, and Control (GNC) algorithms. This is typically the most expensive to develop, test, and verify. Thus, the approach is to preserve the flight software, while first evolving the supporting (such as Command and Data Handling, Caution and Warning, Telemetry, etc.). This can be accomplished by gradually removing the support software from the legacy flight leaving only the algorithms. The support software could be re-developed for modern platforms, while leaving the algorithms to execute on technology compatible with the legacy system. It is also possible to package the algorithms into an emulated version of the original computer (via Field Programmable Gate Arrays or FPGAs), thus becoming a GNC on a Chip solution where it could live forever to be embedded in modern platforms.

Theoretical Background and Prognostic Modeling for Benchmarking SHM Sensors for Composite Structures


 
 
 This paper reports on analytical as well as computer simulation of waves propagating in sandwich-type composite structures. Sandwich-type composites are being studied for use in NASA’s new heavy lift launch vehicle, and flaw detection is crucial for safety and for failure prognostics. Theoretical analysis, as well as numerical modeling, is needed for benchmarking of available technologies for structural health monitoring (SHM) sensors and sensor systems. This benchmarking activity is important for answering the basic question of what minimum flaw size can be detected by the existing SHM based monitoring methods. Sandwich panels with foam, WebCore and honeycomb structures were considered for use in this study. Eigenmode frequency analysis and Frequency Response Analysis of the panels were made to understand fundamental properties of the panel physics and limitations that may affect the application of current SHM sensors and methods. An analytical study of the transient wave propagation is considered based on Mindlin plate theory. The mathematical model, accompanied by numerical simulations, shows that small size defects can be recognized but the frequency of waves should be sufficiently high. It is concluded that a combination of analytical results coupled with the high-fidelity simulations should make it possible to analyze experimental data and to predict the applicability of SHM methods for this type of structure.
 
 

Low Recurring Cost, Partially Reusable Heavy Lift Launch Vehicle

This paper presents a partially reusable, two-stage-to-orbit launch vehicle concept for delivering 65 metric ton payloads to low Earth orbit. A winged booster and an expendable core stage each use identical main propulsion, thrust structure, and propellant feed systems. For both stages, four 745,000 lbf thrust, RS-68 oxygen/hydrogen rocket engines, presently used on the Delta-IV launch vehicle, are used. The booster, which does not require reentry thermal protection, ascends to aMach 2.4, 81,000 ft altitude condition, separates from the core stage, and glides back to a runway landing. Sixty-five metric tons in orbit would be enabling to a variety of exploration missions, including very large telescope emplacement missions, robust outer planet missions, and others requiring large payloadmasses or volumes. Use of a reusable booster, designed formaintainability and affordability, would, in combination with an expendable core using common propulsion, allow for significant reductions in recurring costs compared with a totally expendable vehicle with similar payload capabilities.

1.5.4 Time‐Expanded Decision Networks: A Framework for Designing Evolvable Complex Systems

AbstractThis paper describes the concept of Time‐Expanded Decision Networks (TDN), a new methodology to design and analyze flexibility in large‐scale complex systems. This includes a preliminary application of the methodology to the design of Heavy Lift Launch Vehicles for NASA's space exploration initiative. Synthesizing concepts from Decision Theory, Real Options Analysis, Network Optimization, and Scenario Planning, TDN provides a holistic framework to quantify the value of system flexibility, analyze development and operational paths, and identify designs which can allow managers and systems engineers to react more easily to exogenous uncertainty. TDN consists of five principle steps, which can be implemented as a software tool: 1. Design a set of potential system configurations 2. Quantify switching costs to create a “static network” that captures the difficulty of switching among these configurations 3. Create a time‐expanded decision network by expanding the static network in time, including chance and decision nodes 4. Evaluate minimum cost paths through the network under plausible operating scenarios 5. Modify the set of initial design configurations to exploit high‐leverage switches and repeat the process to convergence. Results can inform decisions about how and where to embed flexibility in order to enable system evolution along various development and operational paths.

Project of Ariane 5 LV family advancement by use of reusable fly-back boosters (named “Bargouzine”)

Abstract The paper concerns possible concept variants of a partially reusable Heavy-Lift Launch Vehicle derived from the advanced basic launcher (Ariane-2010) by means of substitution of the EAP Solid Rocket Boosters for a Reusable Starting Stage consisting two Liquid-propellant Reusable Fly-Back Boosters called “Bargouzin”. This paper describes the status of the presently studied RFBB concepts during its three phases. The first project phase was dedicated to feasibility expertise of liquid-rocket reusable fly-back boosters (“Baikal” type) utilization for heavy-lift space launch vehicle. The design features and main conclusions are presented. The second phase has been performed with the purpose of selection of preferable concept among the alternative ones for the future Ariane LV modernization by using RFBB instead of EAP Boosters. The main requirements, logic of work, possible configuration and conclusion are presented. Initial aerodynamic, ballistic, thermoloading, dynamic loading, trade-off and comparison analysis have been performed on these concepts. The third phase consists in performing a more detailed expertise of the chosen LV concept. This part summarizes some of the more detailed results related to flight performance, system mass, thermoprotection system, aspects of technologies, ground complex modification, comparison analyses and conclusion.

Time‐expanded decision networks: A framework for designing evolvable complex systems

AbstractThis paper describes the concept of Time‐Expanded Decision Networks (TDNs), a new methodology to design and analyze flexibility in large‐scale complex systems. This includes a preliminary application of the methodology to the design of Heavy Lift Launch Vehicles for NASA's space exploration initiative. Synthesizing concepts from Decision Theory, Real Options Analysis, Network Optimization, and Scenario Planning, TDN provides a holistic framework to quantify the value of system flexibility, analyze development and operational paths, and identify designs that can allow managers and systems engineers to react more easily to exogenous uncertainty. TDN consists of five principle steps, which can be implemented as a software tool: (1) Design a set of potential system configurations; (2) quantify switching costs to create a “static network” that captures the difficulty of switching among these configurations; (3) create a time‐expanded decision network by expanding the static network in time, including chance and decision nodes; (4) evaluate minimum cost paths through the network under plausible operating scenarios; and (5) modify the set of initial design configurations to exploit high‐leverage switches and repeat the process to convergence. Results can inform decisions about how and where to embed flexibility in order to enable system evolution along various development and operational paths. © 2007 Wiley Periodicals, Inc. Syst Eng 10: 167–186, 2007

Vortex-induced vibration of a heavy-lift launch vehicle during transonic flight

The Titan IV, like many other heavy-lift launch vehicles, is composed of three bodies. At Mach 1.1, 17-Hz pressure oscillations have been observed on the Titan IV center body. The associated lateral structural responses often exceed in amplitude those for all other flight events. Computational fluid dynamic (CFD) simulations conducted for the Titan IV show that pairs of vortices are shed due to strong crossflow acceleration towards the center body, and that these vortex pairs form periodically on alternate sides of the launch vehicle. The phenomenon is analogous to von Kármán vortex shedding over a cylinder, with Strouhal number 0.14–0.17. The CFD simulations were used to generate forcing functions for structural dynamic analyses. The resulting structural responses are in good agreement with transonic flight measurements. The structural dynamic analyses also show that the degree of alignment of the aerodynamic force amplitudes with the mission-specific structural mode shapes has a strong effect on the flight responses.

A TECHNICAL OVERVIEW OF THE “SUNTOWER” SOLAR POWER SATELLITE CONCEPT

During 1995–1996, the National Aeronautics and Space Administration (NASA) conducted a far-reaching reexamination of the technologies, systems concepts and terrestrial markets that might be involved in future space solar power (SSP) systems. The principal objective of this “fresh look” study was to determine whether a solar power satellite (SPS) and associated systems could be defined that could deliver energy into terrestrial electrical power grids at prices equal to or below ground alternatives in a variety of markets, do so without major environmental drawbacks, and which could be developed at a fraction of the initial investment projected for the SPS Reference System of the late 1970s. One of the key concepts emerging from the “fresh look” SSP study is the “SunTower” SPS system. This concept exploits a variety of innovative technologies and design approaches to achieve a potential breakthrough in establishing the technical and programmatic feasibility on initial commercial SSP operations. Capable of being deployed to either low Earth orbit or middle Earth orbit altitudes and various inclinations, the SunTower concept involves essentially no in-space infrastructure and requires no unique heavy lift launch vehicle. The concept, which can provide power to global market places appears to allow up to a factor of 30:1 reduction in initial investment requirements, compared to the 1979 SPS Reference Concept. This paper presents a technical overview of the SunTower SPS concept, including key technologies, sensitivity trades, operational scenarios. Potential non-SPS space program uses of the SunTower concept and related technologies are identified, including human exploration, space science and commercial space applications.

Hammerhead and nose-cylinder-flare aeroelastic stability revisited

The flow mechanism responsible for the recently discovered buffet-producing critical cylinder length for hammerheads is discussed. For short cylinder lengths, the upstream effects of the hammerhead wake are able to affect the terminal shock location, driving flow separation to the nose-cylinder shoulder. This has the potential to cause aeroelastic instability leading to structural failure. A similar critical-cylinder-length effect exists for cone-cylinderflare configurations. This too involves an upstream flow effect. In this case the flare-induced pressure rise drives the shock-induced flow separation to the cone-cylinder shoulder. Neither of these effects is recognized in the existing NASA guidelines for elastic vehicle design. Some currently proposed designs for heavy lift launch vehicles incorporate dangerously blunt noses, in violation of the NASA aeroelastic design criterion. A reexamination of these nose effects indicates the possibility of aeroelastic instability and structural failure. It is the conclusion of this study that it is imperative to consider aeroelastic stability effects early in the design process in order to avoid the possibility of a flight failure or a costly redesign later in the development cycle if the presence of an aeroelastic stability problem is discovered.

An evaluation of the implementation of transportation systems with unconventional propellants

The paper deals with a more-dimensional evaluation of the benefits achievable by using super high energy triplet helium propellant (He∗) instead of LOX/LH 2. The evaluation criteria were, among others, technical performances, environmental aspects, risk potentials and costs. They were measured by a hierarchy of objectives. Using completely new propellants could revolutionize space travel which is up to now characterized by the use of conventional chemical systems with maximum specific impulses below 500 s at high thrust levels. The necessity of cost reductions is the most important driver. Triplet helium is considered in combination with different working fuels (liquid helium, liquid hydrogen) due to its advantages in comparison with other super high energy propellant candidates: very high specific energy, easy production, high density. It is regarded as being trapped within a cryogenic lattice of solid helium or solid hydrogen. Two different launch vehicles are analysed to deliver required data for the evaluation: a SLLV (small lift launch vehicle) carrying 7 Mg of payload, and a HLLV (heavy lift launch vehicle) carrying 120 Mg of payload. The vertically launched ballistic vehicles are fully reusable. The investigation used a long term space traffic scenario (R. E. Lo, J. Laßmann and M. Thierschmann, paper presented at the 42nd IAF Congress, Montreal[1]) as background. Degrees of goal achievement were determined with the help of a computer code using complex planning algorithms. Operational costs of the alternative concepts are presented. It is shown in the paper, that the implementation of transportation systems with super high energy triplet helium propellant is beneficial in some areas compared to conventional LOX/LH 2 systems. Vehicle volumes and masses as well as operational costs will be reduced. However, according to the present state-of-the-art, insurmountable technical problems arise against the realization of such propulsion systems.

United States commitment to heavy lift launch vehicles

Observers of the United States' space program will note progress toward the development of a new launch system capable of supporting the nation's future space missions. The process of defining mission requirements, developing technically and politically acceptable solutions, making policy decisions, and developing budget support in a democratic society is protracted, but eventually yields decisions that represent the public interest. The consensus developing within the United States on a new launch capability including heavy-lift is embodied in the Joint NASA/DoD National Launch System. This launch vehicle concept has emerged after more than five years of studies by NASA, the DoD and every major industrial aerospace contractor in the U.S. In July 1991, Vice President Quayle, in his capacity as Chairman of the National Space Council stated the Nation's commitment to support of the NLS. This paper reviews progress to date, and the involvement of the four major constituencies; the Executive Branch operating through the National Space Council, the Legislative Branch, the various elements of the DoD, and NASA. The evolution of launch system “requirements”, along with the form, content and rationale for the various decisions that have been made will be described and discussed.

Lunar base initiative 1992

The return to the Moon is no longer a question of yes or no, but a question of when and how. The first landing of a human being on the lunar surface in 1969 was a purely national effort of the U.S.A. Building a lunar base and operating it in the next century is rather a task for all nations of this planet, even if one nation could do it alone. However, there are several alternatives to carry out such a program and these will and should be debated during the next years on an urgent basis. To do this, one has to take into account not only the historical accomplishments and the present trends of cooperation in space programs, but also recent geopolitical developments as well as the frame of reference established by international law. The case for an International Lunar Base (ILB) has been presented to the International Academy of Astronautics on 11 October 1987 by the IAA Ad Hoc Committee “Return-to-the-Moon”. This draft of a position paper was subsequently published in Acta Astronautica Vol. 17, No. 5, (pp. 463–489) with the request of public debate particularly by the members of the Academy. Some 80 Academicians responded to this invitation by the President of the Academy and voiced their opinions on the questions and issues raised by this draft of a position paper. This led to a refinement of the arguments and assumptions made and it is now possible to prepare an improved position paper proposing concrete steps which may lead to an ILB. An issue of this proportion must start with a discussion of goals and objectives to be arranged in some kind of a ranked order. It also has to take note of the limitations existing at any time by the availability of suitable space transportation systems. These will determine the acquisition date and rate of growth of a lunar base. The logistics system will also greatly influence the base characteristics and layout. The availability of heavy lift launch vehicles would simplify the task and allow to concentrate the construction activities for a lunar base on Earth where it is done the cheapest way. Extraterrestrial activities by men should be kept as small as possible to keep costs down. The organizational alternatives have an equally wide span and many options have been considered already. The most prominent ones are described and the results of a ranking exercise are presented. Finally, a phased project plan as seen from today's viewpoint is proposed beginning in 1992 with the activation of a “Lunar Base Planning Office” to be followed by an “International Lunar Development Agency” with the goal of establishing the first element of a permanent lunar base in the second half of the first decade of the 21st century.

Integrated launch and emergency entry vehicle concept

This paper describes the design of an integrated launch and emergency entry vehicle (EEV) that can satisfy the need for an advanced manned vehicle, a heavy-lift launch vehicle, and the Space Station. It is pointed out that, because only one small entry vehicle would need to be developed, the development costs should be relatively low. The EEV would have reasonable operating costs because its expendable tank would be smaller than that of the Space Shuttle and all expensive parts would be reusable. Schematic diagrams are included.

Space transportation architecture study overview

This paper covers the scope of the Space Transportation Architecture Study (STAS), summarizes the findings derived to date from this multi-task effort, and indicates its relationship to the recently initiated heavy-lift launch vehicle definition effort. The study is being jointly funded and directed by the Department of Defense (DoD) and NASA. Purposes of the study are to identify attractive architectural and transportation system options, establish technology road maps and decision points for the implementation of the next generation of space transportation systems, and prepare conceptual design definitions, programmatic data, and technology plans for selected mid-to-late 1990s transportation systems. This STAS overview covers the mission model sets considered and the resulting preferred architecture options. Trends and findings to date are presented along with specific observations relative to requirements for future launch vehicles.

Trends in space transportation

Near-future goals of international launch systems are aimed at placing payloads of at least 5000 kg into geosynchronous earth orbit (GEO). In the United States, this will be accomplished by the Shuttle with a new upper stage and complementary expendable launch vehicle (CELV) such as the Titan 34D7/Centaur. The Soviet Union's efforts will also achieve this goal and the European Space Agency's (ESA) Ariane 5 will approach it. It appears clear that the U.S. will revert to a mixed fleet policy, utilizing the Shuttle only for those missions where its capacity is needed or where manned presence is a necessity. The ESA Hermes and the Soviet shuttle will also be chiefly used in the latter capacity. In the United States and the Soviet Union, much thought and some funds are being devoted to the study of third-generation space transportation systems. The objectives are to achieve either/or ready access to space, low cost per pound to orbit, and very heavy weights (at low cost/pound) to orbit. Concepts such as the AerospacePlane and HOTOL (horizontal take-off and landing); the Shuttle-derived vehicles (SDV), and mammoth heavy lift launch vehicles (HLLVs) are being studied. The third generation of launch vehicles will serve both civilian and military needs. Civilian applications represent a myriad of advanced needs. They range from the normal extension of present communications, earth observations, in-space manufacturing, and space station and other manned operations to the more exotic missions of Mars expeditions (both manned and unmanned), lunar bases, and large space-based power systems. Military applications are likely to include advanced intelligence and reconnaissance systems, spacecraft servicing and maintenance tasks, support of the Strategic Defense Initiative (SDI) systems, and possibly a permanent manned presence in space. Both civil and military aims may lead to the development of the AerospacePlane. This vehicle could evolve into forms designed for high speed air and space transportation and flexible response missions. This paper describes the present thinking and early plans of medium launch vehicles, advanced shuttles, and AerospacePlane-type vehicles. Shuttle-derived and heavy-lift earth to low orbit systems are discussed, along with the ESA/Centre National d'Etudes Spatiales (CNES) Hermes and Soviet shuttle concepts.