A Civil Engineer's View from Space

From the perspective of a 250‐nautical‐mile orbit aboard the Space Shuttle, the author has had the opportunity to observe the effects of man on the earth, to reflect on his future in space, and to examine the role civil engineers may have in building our future. In the decades to come, civil engineers will require skills that are not currently provided by universities and which are not adequately represented in professional societies. All disciplines of the civil engineering profession will need to examine their strategies to enable them to establish a significant place on the team. From launch pads to remote sensing satellites, from space stations to lunar bases, civil engineers can and should play a significant role in design requirements, engineering, testing, assembly, and operation. The Aerospace Division of the ASCE should take the lead to insure that civil engineers are prepared to meet the challenge.     

A Different Race: The Philosophy

The infrastructure of a nation is the foundation of the nation's ability to compete in world markets, maintain a credible deterrence, influence other nations, and create surpluses for use in social programs. Part of the infrastructure that a nation will depend on economically and militarily in the 21st century will be located in space. Space, besides being an economic, technical, and strategic opportunity for various companies and countries, can also be a way to use engineering and technology to improve the condition of the human race. This paper explains a strategy for reprogramming money from the development and deployment of strategic offensive weapons and their delivery systems to developing the facilities and capabilities needed for nations to be active participants in the exploration and industrialization of space. The creation of the infrastructure needed to pioneer the space frontier will require all engineering professions, especially civil engineering, to stretch and reach for the stars.     

Science and Engineering for Space: Technologies from Space 88

This paper highlights technology development for space exploration. It draws on the proceedings of Space 88, Engineering, Construction, and Operations in Space, which includes 125 papers and 1,349 pages providing in‐depth discussions of space policy, extraterrestrial basing, space stations, orbiting structures, and areas of special interest. In the space station and orbiting structures (orbital facilities) section, papers discuss the engineering, construction, and operations of orbiting space systems. Papers in the extraterrestrial basing section deal with the engineering, construction, and operations challenges faced in development of bases and operations on extraterrestrial bodies. The special interest (interacting disciplines) section provides a discussion of challenges facing us in meeting needs for space power, life support, human factors, astronomy, education, and management. The purpose of this volume on engineering, construction, and operations of facilities and bases in space is to encourage and stimulate the development of the required technologies. The concluding section of this paper focuses on space policy and a view toward the future.     

Multiterrain Earth Landing Systems Applicable for Manned Space Capsules

A key element of the President’s Vision for Space Exploration is the development of a new space transportation system to replace Shuttle that will enable manned exploration of the moon, Mars, and beyond. The National Aeronautics and Space Administration has created the Constellation Program to develop this architecture, which includes the Ares launch vehicle and Orion manned spacecraft. The Orion spacecraft must carry six astronauts and its primary structure should be reusable, if practical. These requirements led the Constellation Program to consider a baseline land landing on return to earth. To assess the landing system options for Orion, a review of current operational parachute landing systems such as those used for the F-111 escape module and the Soyuz is performed. In particular, landing systems with airbags and retrorockets that would enable reusability of the Orion capsule are investigated. In addition, Apollo tests and analyses conducted in the 1960s for both water and land landings are reviewed. Finally, test data and dynamic finite-element simulations are presented to understand land landings for the Orion spacecraft.     

Engineering Issues for Early Lunar‐Based Telescopes

A telescope on the Moon is needed for astronomy and can be constructed in this decade or early in the next century. Design for this telescope will be fundamentally different from the design of free‐flying telescopes. Its design will be more like the new Keck telescope being completed on a mountaintop in Hawaii than the Hubble Space Telescope, in low Earth orbit. Success of the lunar‐based telescope will depend on an appropriately engineered structure, a suitable interface (foundation) in the lunar soil, and a carefully thought out construction process. Participation of engineers in identifying and resolving issues for this extraterrestrial engineering and construction project is a natural extension of the traditional engineering role, and will prepare the engineering and construction communities for the subsequent greater challenges associated with basing on the Moon. These communities need to document now the types of data and information that NASA should obtain in the next early lunar missions so that construction on the Moon will be facilitated.     

Hypervelocity Impact Penetration Phenomena in Aluminum Space Structures

All long‐duration spacecraft are susceptible to high‐speed impacts by meteoroids and pieces of orbiting space debris. Damage to critical spacecraft systems caused by such impacts can lead to spacecraft failure and loss of life. In order to develop adequate protection against penetration for crew compartments and other critical spacecraft systems, an aerospace design engineer must possess a full understanding of the penetration mechanics involved in the hypervelocity impact loading of a variety of structural components. This paper describes the results of an experimental investigation of the penetration phenomena associated with oblique hypervelocity projectile impact of aluminum dual‐wall structures. Equations that quantitatively describe these phenomena are obtained through a regression of hypervelocity impact test data. These equations characterize observed penetration phenomena as functions of the geometric and material properties of the impacted structure and the diameter, obliquity, and velocity of the impacting projectile. A review of the test data shows that oblique hypervelocity impact penetration phenomena are strongly dependent on impact obliquity and therefore can differ significantly from those associated with normal high‐speed impacts. It is concluded that the possibility of non‐normal impacts and their effects on structural integrity must be considered in the design of any structure that is to be exposed to the hazardous meteoroid and space debris environment.     

Concept of Adaptability in Space Modules

The space program is aiming towards the permanent use of space; to build and establish an orbital space station, a Moon base and depart to Mars and beyond. We must look after the total independency from the Earth's natural resources and work in the design of a modular space base in which each module is capable of duplicating one natural process, and that all these modules in combination take us to conceive a space base capable of sustaining life. Every area of human knowledge must be involved. This modular concept will let us see other space goals as extentions of the primary project. The basic technology has to be defined, then relatively minor adjustments will let us reach new objectives such as a first approach for a lunar base and for a Mars manned mission. This concept aims towards an open technology in which standards and recommendations will be created to assemble huge space bases and spaceships from specific modules that perform certain functions, that in combination will let us reach the status of permanent use and exploration of space.     

Preimpact Configuration Analysis of Dual-Arm Space Manipulator Capturing Object

Based on momentum conservation principle of space manipulator, this paper presents precapture configuration of space manipulator capturing object. Two unique precapture configurations, “straight-arm capture” (SAC) and “generalized straight-arm capture” (GSAC), were proposed based on the single-arm system; then GSAC was extended to the dual-arm system and the corresponding angular relation was obtained. This configuration satisfies GSAC and can reduce the coupling angular momentum during capture operation and the burden of postimpact control. This avoids the limitation of joint velocity when controlling the compound (manipulator and object) and guarantees the stability of system. The simulation results show the effectiveness of this method.     

Engineering Test Support for Construction in Space

A number of engineers and constructors have been looking at the engineering analyses and syntheses associated with preparations for the establishment of a base on the Moon and human flight to Mars. This paper discusses the importance of early involvement of the engineering test perspective and approach in the engineering analysis, design, and development of capabilities for this construction activity in space, especially construction that incorporates the use of extraterrestrial resources. The effectiveness and suitability of mission equipment and proposed resource extraction processes must be shown by analysis, simulation, ground test, and flight test. Facilities and resources for test and evaluation (T&E) of extraterrestrial facilities must be acquired in a timely fashion, and time must be allowed for T&E.     

Modular Spacecraft

Instead of a pessurized cylinder serving as the basic module for space stations, certain polyhedra are studied having the all‐space filling property, permitting the construction of pressurized volumes of cylindrical or virtually any conceivable shape. Rotatable forms for artificial gravity become an option because loads are evenly distributed through a triangle‐based grid work. This grid work may be left open, or panelled and pressurized partially or totally. The isosceles tetrahedron is an especially useful member of a class of polyhedra that may be stacked face to face in three dimensions without leaving space among the units. Since only a few simple parts must be duplicated, the approach is economical as well as flexible. Components may be shuttled into orbit in the disassembled state so that a substantial space station may be established with a single flight. Reconfiguration is possible as requirements change. Conversion to translunar or interplanetary craft is also conceivable. On arrival such craft may again be reconfigured to fulfill several roles simultaneously: orbital support craft, lander, and surface base.     

System for Orbital Recovery of Space Shuttle's External Tank

The orbital recovery of the external tank (ET), backbone of the U.S. space transportation system, can be considered enormously important for the future development and colonization of space. America's ability to respond to the many space opportunities on the horizon of research, commercialization and planetary science depend on the resiliency of the space transportation system, and especially on the use of the external tank in space. The use of ETs—as launch stages for planetary exploration, as large platforms in either low Earth orbit or geosynchronous Earth orbit to coorbit with other payloads requiring human interaction, or as an element of support for the next part of space station Freedom—could be of fundamental importance. The purpose of this paper is to describe a method for the orbital construction of the device and the corresponding recovery of the ET.     

Space Hotels: Civil Engineering’s New Frontier

This paper reviews the prospects for the development of commercial hotels in space; it shows that it is increasingly accepted that this could become a lively new field of business within little more than a decade. The key enabler is the availability of low-cost access to space through the operation of reusable passenger-carrying launch vehicles, the development of which requires investment equal to no more than a few months worth of existing space budgets. When this becomes available, competition will lead to rapid development of progressively more exotic facilities in orbit as companies exploit the unique environment of space to provide guests with ever more popular services. Discussed are some of the civil engineering topics that will arise as orbital accommodation grows from assemblies of prefabricated modules to large structures assembled in orbit, including rotating structures offering “artificial gravity,” and eventually to buildings on the lunar surface.     

Sociology of Professions: Application to the Civil Engineering “Raise the Bar” Initiative

This paper applies the sociological theory of professions, as espoused by Abbott and Freidson, as a conceptual framework to assess the critical issues associated with the ongoing implementation of ASCE Policy Statement 465—also called the “Raise the Bar” initiative. The sociology of professions provides an objective basis for evaluating key aspects of the initiative, including publication of the civil engineering body of knowledge, raising educational standards for licensure, collaboration with other engineering disciplines, and defining the role of paraprofessionals. The analysis demonstrates the following: (1)?the models of professionalism by Abbott and Freidson are highly applicable to civil engineering; (2)?most aspects of Policy Statement 465 implementation are consistent with these models; (3)?the initiative is contributing to the strength of the profession as intended; and (4)?some future additions and adjustments appear to be warranted. From this analysis, the author derives recommendations for the future direction of the Raise the Bar initiative.     

Railgun Space Launcher

A method and facilities for delivering payload and people into outer space are presented. This method uses, in general, engines located on a planetary surface. The installation consists of a space apparatus, power drive stations, which include a fly-wheel accumulator (for storage) of energy, a variable reducer, a powerful homopolar electric generator, and electric rails. The drive stations accelerate the apparatus up to hypersonic speed. The estimations and computations show the possibility of making this project a reality in a short period of time (for payloads that can tolerate high g forces). The launch will be very cheap at a projected cost of $3–$5/lb. The authors developed a theory of this type of the launcher.     

Educating Civil Engineers to Work in Space

This paper addresses the role of civil engineering in space operations and its impact on undergraduate education. The history of civil engineering and its role in society is discussed. The increasing complexity of the civil engineer's responsibilities from ancient times to the present is articulated. New civil engineering challenges fostered by man's quest to explore and inhabit the solar system and beyond are addressed. These challenges give rise to new requirements for the undergraduate education of tomorrow's civil engineers. The U.S. Air Force Academy's attempt to respond to these new undergraduate requirements is described. The civil engineering curriculum at the Air Force Academy emphasizes preparation for the unique challenges associated with space exploration and habitation. It is described and presented as a model for other undergraduate civil engineering programs that wish to focus on aerospace engineering activities into the 21st century.     

Variational Technique for Spacecraft Trajectory Planning

This paper describes a spacecraft trajectory planning algorithm based on the calculus of variations which can solve 6-degree-of-freedom spacecraft docking and proximity operations problems. The design of a cost functional which trades off fuel use, obstacle clearance distance, and arrival time is discussed. The nonlinear orbital dynamic equations are treated as dynamic constraints. The Euler-Lagrange equations for this functional are derived, as is the Pontryagin criteria for the optimal control input given realistic saturating on-off thrusters. The indirect collocation method is chosen to solve the attendant boundary-value problem for its lack of sensitivity to initial conditions; continuation is used to further improve the algorithm’s robustness. The manipulation of the Euler-Lagrange equations and the transversality condition into a form suitable for use with existing collocation codes is discussed. Results are shown for an end-to-end docking maneuver with a tumbling satellite.     

Use Value Engineering Concepts for Spaceport Launching

In simple terms, value engineering (VE) identifies the function of a system with a verb/noun and assigns it a value. This paper provides a background phase that briefly identifies the Soviet's launching capability. A lesson has been learned from the former U.S.S.R.'s success with massive booster rockets. Their version of the shuttle has been tested and will become an integral part of their fleet. The use of VE concepts for spaceport launching will allow existing facilities to be converted for handling a new generation of expendable launch vehicles (ELV). The paper postulates that not all ELVs have to be assembled in buildings. It also suggests that the hoisting system used for vehicle assembly does not have to be 300–500 ft off the ground. The VE proposal identifies mobility as the key factor for elimination of space‐aged dinosaurs. Modular construction can permit support services and equipment to be mounted on large crawler transporters and be able to move with ground support. A mobile spaceport launching system could traverse up and down Cape Canaveral or Vandenberg AFB at about one‐half the present launch support cost.     

Lunar Dust Levitation

Observations of a lunar “horizon glow” by several Surveyor spacecraft on the lunar surface in the 1960s and detections of dust particle impacts by the Apollo 17 Lunar Ejecta and Meteoroid Experiment have been explained as the result of micron-sized charged particles lifting off the surface. The surface of the Moon is exposed to the solar wind and solar UV radiation causing photoemission, so it develops a surface charge and an electric field near the surface. Dust particles injected into this plasma from the lunar regolith, whether from human and mechanical activity or from meteoroid impacts or electrostatic forces, may be stably levitated above the surface and may undergo preferential deposition onto areas of the lunar surface (or equipment) with different electrical properties. This can lead to a net transport as well as contamination of sensitive equipment. This paper reports on new experimental measurements and numerical simulations of the plasma environment above the lunar surface and the related behavior of charged dust.     

Jacob Hays Linville: A Little Known Giant of Civil Engineering

Men who shaped the Civil Engineering profession in the 19th century, especially the bridge builders, are virtually unknown to engineers of the 21st century. This paper is about a man who was one of the most prolific bridge builders of the period from 1860 to 1880 when railroads began to cross major rivers of the country. He built several long span bridges over the Schuylkill, Ohio, Mississippi, and Missouri rivers. He set the record for railroad truss bridge span on three occasions starting at 320?ft going to 420?ft and in 1877 building a span of 520?ft. He developed the pin connected Whipple double intersection truss by placing wrought iron links in the lower chord, built up riveted plate wrought iron upper chords and posts built of two or more wrought iron shapes riveted together.     

Next Generation Space Telescope. II: Proposed Pointing Control System

The pointing control system of the Hubble Space Telescope (HST) represents the current state of the art for the precision control of a large spacecraft. The proposed Next Generation Space Telescope (NGST) will require an order‐of‐magnitude increase in pointing resolution over that of HST. The use of active optics in the form of a steerable secondary mirror has been proposed for NGST to satisfy these requirements. The primary motivation for this study was to demonstrate the feasibility of satisfying the pointing‐stability requirements by sensing the guide‐star position and steering the optical path of the telescope with the active secondary mirror. To study the requirements of the control system, a two‐degree‐of‐freedom model that retains the rigid‐body mode of the telescope as well as its first oscillatory mode was constructed. The corresponding optimal control law was developed and implemented in a discrete manner to examine the behavior of the system subject to typical spacecraft excitations.