Civil Engineering in Space

Our terrestrial experience with toxic remediation, realized recycling efficiency, natural resource management, and other sustainable civil engineering impacts should universally apply to our future space suburbia.

An Expensive Cup of Coffee

Consider the complex and expensive process of lifting materials into orbit and keeping them balanced against the grasp of earth's gravitational field. Just moving a pint of water into high earth orbit is estimated to cost over $15,000 US and takes months of multidisciplinary engineering. Currently there is no reason to believe similar factors will not apply for any inhabitable body in space for many years to come. From this standpoint alone, once hypothetical materials transportation to these large bodies has been accomplished it would make sense to keep them there, under control and under no circumstance wasted or discarded. This was a primary impetus for recently lifting a high tech urine recycling unit to the international space station, because $7,500 is a lot to pay for a one way rental on a cup of coffee.

Orbiting Debris an Ungoing Challenge

But there are other subtle yet no less important reasons to think about sustainable extraterrestrial development. The present concern over man-made locally orbiting debris is a good example. Decades of near earth utilization has led to an orbiting cloud of now useless materials from collisions, failed placements, obsolescence, malfunctions, butter fingers, and fail-safe destruction (because rocket science doesn't incorporate “self recycle” mechanisms in vehicles and equipment, rather “self destruct and worry about cleanup some other time” mechanisms are typically employed).

Recovering this debris is not just a matter of sending a garbage scow scuttling around the orbital arena. These objects travel at different speeds, orbits, and directions, with sizes ranging from less than one centimeter to entire derelict satellites. And the orbital mechanics involved are not trivial, relative velocities alone can be tens of thousands kilometers per hour. The long term consequences of this buildup are constant monitoring and extrapolation to avoid further damage to equipment and astronauts attempting to do useful work. Currently prevention is one and possibly the only cure in this all too real scenario.

Space as Infinite Garbage Disposal?

There was a time when earth's oceans were viewed as a vast, immutable repository for waste and excess. “Dilution,” as the saying went, “is the solution to pollution.” Time and knowledge has shown how misguided this view had been.

Neither should extraterrestrial endeavors view the infinite space environment as the infinite waste disposal. Even the extremely limited visits to the moon over the past 40 years have left an estimated 300,000 pounds of scientific instrumentation, memorials and memorabilia, excess equipment, and outright trash. Interestingly, there are no “cradle to grave” specifications for any off-earth materials, which has resulted in some political turmoil regarding international responsibilities for unused materials in space. Perhaps a few tried and tested terrestrial axioms should still apply:

1. What goes around, comes around. Never truer than in orbital dynamics.

2. Waste not, want not. Got it, own it, recover it, use it again.

3. Design with the end in mind. Decommissioning should be the start of something useful.

Getting these principles into extraterrestrial development planning is hopefully going to be an obvious choice.

Extraterrestrial Resources - Mining Asteroids

For example, utilizing extraterrestrial water, minerals, gases and other resources should give more than a passing glance at waste generation and handling. A fairly realistic illustration of axiom #1 in this example would be an extractive mining development on a solar orbiting asteroid or planetoid. It may be convenient to simply eject tailings away from the asteroid as the extraction process progresses. As trivial as the amount of tailings may seem, the change in total asteroid mass from the ejected tailings and the extracted products can measurably change the orbital trajectory of the asteroid.

It could be argued that in the vastness of space, such small trajectory adjustments and debris are of no consequence assuming they are properly plotted and extrapolated. It could also be argued that same vastness leaves many possible extrasolar encounters and influences unaccounted for… which begins to appear as the start of another orbiting debris cloud, only much larger and with more dire consequences.

Water Usage and Recycling

To help illustrate axiom #2 our unquenchable need for water can be used. Surprisingly, when water usage is modeled for extraterrestrial consumption in a closed system, the largest amounts are used for cleaning and not for drinking or cooking. Until adequate off-earth water resources are being utilized, even the lowly septic system becomes quite a sustainable design challenge for even the smallest habitation. This in fact may be the limiting factor in engineering anything close to a sprawling off earth metropolis, which partially explains the current emphasis on finding and utilizing extraterrestrial water in an efficient, cost effective manner.

Repurposing Civil Engineering for Space Engineering

For axiom #3 there are many far future applications like self healing polymers, memory metals, nanobots and the like which are targeted for use in self maintenance and reassembly, or even final disassembly into reusable materials. There are also present day and near future design applications as well; pavements, metals, wood, polymers, and other materials are constant targets of civil engineering re-purposing. Self servicing, automated repair systems and unlimited reuse of raw materials are also becoming the holy grail of sustainable engineering endeavors. Self healing coatings and flexible “poured stone” products are a reality today. Presumably combined terrestrial and extraterrestrial research efforts will eventually result in making the terms “trash”, “disposable” and “construction debris” avoidable anachronisms.

So while it takes cutting edge rocket science to get there, it will take sustainable civil engineering to live there.

What's Next?

Surviving a remote and possibly harsh environment in an extraterrestrial setting is a matter of being highly self-reliant. This means habitations, developments, and colonies should be considered “closed systems,” able to sustain themselves without external input. Please click the next section below to continue.

Civil Engineering: Soil Mechanics and other Geotechnical Topics at Bright Hub

Studying the behavior of earth materials is a vast subject that includes the study of soil properties, foundations, slopes, risk mitigation, and ground improvement methods. The following topics will guide you through much of the terminology and theory of geotechnical engineering and soil mechanics.

Introduction to Geotechnical Engineering

Geotechnical engineering is often the starting point for studies for every practicing civil engineer. Thus it's important to understand how geotechnical aspects affect the development of civil engineering projects and construction works. Here, in this list of articles on the topic, we start with the basics, introducing geotechnical engineering and how it relates to the other branches of civil engineering. Questions that can be asked and answered include how geoenvironmental engineering and geotechnical engineering differ, and what place soil mechanics and rock mechanics hold in the field.

• Fundamentals of Geotechnical Engineering: Everything You Should Know
• Major Differences between Geotechnical and Geoenvironmental Engineering
• The Best Geotechnical Engineering Publications and Online Resources
• Importance of Conducting Geotechnical Surveys
• About Soil Engineering
• What is Rock Mechanics
• Common Terms Applied to Rock Mechanics in Geotechnical Engineering

Soil Mechanics Study

Before any construction work can start, we need to study the behavior of soils. This is covered in soil mechanics and includes the study of mineralogy, soil composition and types, and the shear properties of soils. Soil mechanics provides knowledge about the characteristics and the behavior of the underlying soil, which is important in the design and construction of structures such as bridges, buildings, highways, and dams. Soil properties, in fact, determine the type of structure to be built.

Soil mechanics study is also important because the principles of soil mechanics are also used in related disciplines such as hydrology and soil physics. In this group are articles about soil classification, soil formation, soil properties, and other related aspects of soil mechanics.

• How Soils are formed - Geotechnical Topics: Formation of Soils
• Classification of Soils under Different Classification Systems
• Properties of Soils: Study of Chemical and Physical Properties
• Geotechnical topics: Soil Permeability
• Geotechnical Topics: Soil Compaction
• Understanding Geotechnical Soil Reports

Different Soil Tests

Geotechnical examination is important in order to build strong and durable structures above the soil. Studying soil properties means conducting various studies to determine various factors like grain size, plastic limit, shear stress, loading tests, and other tests. Various laws are used in the determination of these properties, among which Darcy's Law is one of the most commonly used. You'll also learn about the role of soil properties in a failure of a structure like a bridge or a building.

• Passive Lateral Earth Pressure, Bearing Capacity, and Shear Stress in Cohesive Soils
• Darcy's Law for Modeling Groundwater Flow
• Geotechnical Analysis and Examination
• Testing Permeability of Soil
• Reasons for Construction Failures
• Methods of Soil Compaction Remediation

Implementing Results from Studies and Tests

After completing the geotechnical studies of site soil mechanics, we can start with the real work: the construction work. At this point, all the results and reports have been compiled, and accordingly the appropriate construction methods, equipment, and soil preservation methods have been determined. Different types of equipment like rollers, compactors, leveling devices, and other heavy machinery are used to move forward in this phase. Here we have articles related to soil investigations while constructing foundations using different methods like auger boring, core drilling, and percussion boring.

Natural soil preservation methods that help to maintain ecological balance and achieve optimum geotechnical properties also talked about in the articles in this section. Because foundations come in direct contact with the soil, we include articles related to pile foundations and best foundation construction methods. The articles in this section also provide detailed information about engineering sciences related to geotechnology like geosynthetic and geology and other modern age technologies, which are relatively new but closely related to geotechnical engineering studies.

• Practical Methods of Soil Preservation
• Different Types of Soil Compaction Equipment
• Soil Investigation for Foundations
• Introduction to Pile Foundations
• Building Foundations : Best Practices
• Erosion Control Using Geosynthesis
• Methods of Cliff Stabilization
• Studying Earth Sciences Geology

The articles included in this guide will provide a great information source for those interested in geotechnical studies in the civil engineering field. The articles cover the most fundamental aspects of geotechnical engineering where they are important: soil mechanics and rock mechanics, suitability testing for structural erection, natural and engineered methods of soil preservation, erosion control and cliff stabilization, including geosynthesis techniques, and the common civil engineering role of preparing for foundations and civil structures.

Suitability testing can include soil analysis and testing as well subsurface testing (bore and auger sampling). In fact, a large part of the role of the geotechnical engineer involves helping to prevent structural failures that endanger human life and materials. Such failures always indicate the lack of load-bearing capacity of some element (the foundation, structure, or the soil beneath them both), and the geotechnical engineer, for having the responsibilty for determining the suitability of the site, is always at the front lines of the investigation.

Marine Engineering: Ship's Systems and Controls

Numerous different ships systems and controls being maintained by engineer officers are used on all types of vessels today. These consist of engine room systems such as lube oil, fuel oil, and seawater, along with deck officer's roles such as cargo recording and navigation.

Management of the Various Systems Within the Engine Room and Deck Departments

A ship could not function without management of the systems incorporated within her hull and deck. The following sections provide articles on this subject, and I have put these in their relative groups with a brief description. The subjects have been divided under general headings and linked to articles written by myself and other Bright Hub writers in the Marine Engineering channel. We begin with the various systems and controls within the engine room, before moving onto examples in the deck department.

Ships Electrical Systems

The electrical power is supplied from the generators to the main switchboard from where it is distributed to all parts of the ship through numerous breakers and relays. It is maintained by the Electrical / Electronics Engineer. There are normally three generators, one running and supplying power, one on standby, and one down for maintenance whilst at sea. When maneuvering or alongside working cargo, two generators share the load with the other on standby.

Lube Oil Systems

The lube oil system comprises of the main engine sump, suction and discharge filters, circulating pump, coolers and centrifuge. The sump is the main storage tank, located under a grill in the crankcase. The suction and discharge filters remove any particles contained in the oil. (Any pieces of white metal in these could indicate bearing wiping, and must be investigated)

The cooler is required to maintain optimum temperature and viscosity and cools the oil using seawater that passes through tubes or plates depending on the type of cooler.

Regular centrifuging of the oil is essential for removing particles and water from the oil sump; some engines have the centrifuge running twenty-four hours a day; only being stopped for cleaning.

• Effects of not maintaining Lube oil system.
• Crankcase Lube Oil System
• Lube Oil Used in Marine Diesel Engines
• Lube Oil Cleaning by Centrifuging
• Use of Lubricants Aboard Ship
• Marine Oil Piston Cooling Using Lube Oil
• Treatment of Marine Engine Lube & Fuel Oil
• When Should Lube Oil be Changed
• Operation of Marine Lube Oil System
• Problems in the Lube Oil System
• Boundary and Fluid Film Lube Oil Systems
• Cylinder Liner Lube Oil System
• Wet & Dry Lube Oil Sumps
• Types of Lube Oil Systems

Heavy Fuel Oil System

The majority of ships engines use heavy fuel oil (HFO) being a by-product of crude oil refining. It is taken on board ships as bunkers, a sample of which should be checked by the Chief Engineer, as some suppliers abroad have been suspected of mixing old sump oil and even scavenge drains with bunker oil.

Before use in the main engine the HFO must be processed by heating, filtration, purifying, and clarifying. The heating is to keep the oil from waxing and improve the usually high viscosity; filtration is carried out at various stages of the process to remove particles. Purifying removes the water and sludge in the HFO, and clarification removes the solids.

• Preparation of Heavy Fuel Oil
• Handling, Storage and Use of Heavy Fuel Oil
• Marine Heavy Fuel Oil Contaminants
• HFO from Crude Oil Refining
• Taking on HFO Bunkers
• Marine HFO Management System
• Treatment of Marine Engine Fuel & Lube Oil
• Centrifuging Heavy Fuel Oil

Ship’s Deck Systems and Control

The Deck Officers use various methods to control the various systems of navigating, tank cleaning, steering the ship, or control of the cargo. Control of the cargo and producing a cargo plan is also the duty of the Deck Officers, usually the mate or Second Officer. It is a very important document required to keep a record of the type, description, and weights of the various pieces of cargo stored in the holds or on deck. It also notes its location as well as the sequence of loading, and thus the reverse order of discharge, in the various ports of call.

Ship’s Cargo Plan

Navigation System

The bridge is the Deck Officers domain. When I was at sea as an engineer, I used to go up to the bridge when off watch and marveled at the sophisticated navigation gear even in those far off days of 40-odd years ago.

This consisted of the auto-pilot, gyro-counter, radar screen, ship's speed and distance run, all neatly arranged on the bridge. The links below provide further information on this subject.

• Use of Marine Navigation Lights
• Marine Navigation Terminology
• Rules for Ship’s Navigation
• Use of the Magnetic Compass in Navigation
• Electronic Navigation Chart Explained
• Tour of a Ship’s Bridge
• Marine Navigation Using GPS
• Transiting the Panama Canal
• Tools used in Celestial Navigation

Cargo Tank Cleaning Systems on Oil Tankers

When I was an engineer at sea, I used to dread the tank cleaning as the whole ship smelt like a petrol station forecourt! However it must be done in preparation for the next cargo. Gas freeing of the tanks is carried out first, with this being a combination of inert gas flooding and venting of the tanks.

Gas freeing and tank cleaning is under the remit of the Deck Officers; the Chief Officer normally being in charge of operations.

Tank cleaning occurs after discharge of cargo and gas-freeing, usually while on the sea voyage to the next loading port. The following two links explain the process involved in these systems.

• Gas Freeing and Tank Cleaning on Oil Tankers
• Inspection of Cargo Tanks on Oil Tankers

Ships Ballasting Systems

This is under the control of the Deck Officers using their own pumps in the pump-room or requesting the use of the engine room seawater on deck pump. Ballasting is carried out as the cargo is loaded or discharged to maintain the ships stability. There has been a lot of controversy lately regarding taking ballast on in one port and discharging in another port. This can transport and transfer alien species that will wreak havoc with the local flora and fauna.

• What is Ballast Water
• Problems Encountered in Discharging Ballast Water
• Ballast Water Management