Stanford Torus - Orbital Space Habitat

The Stanford torus is a proposed design^[1] for a space habitat capable of housing 10,000 to 140,000 permanent residents.^[2]

The Stanford Torus was proposed during the 1975 NASA Summer Study, conducted at Stanford University, with the purpose of speculating on designs for future space colonies.^[3] (Gerard O'Neill later proposed his Island One or Bernal sphere as an alternative to the torus.)^[4]Wernher von Braun^[5] and Herman Potočnik.^[6] "Stanford torus" refers only to this particular version of the design, as the concept of a ring-shaped rotating space station was previously proposed by

It consists of a torus, or donut-shaped ring, that is 1.8 km in diameter (for the proposed 10,000 person habitat described in the 1975 Summer Study) and rotates once per minute to provide between 0.9g and 1.0g of artificial gravity on the inside of the outer ring via centrifugal force.^[7]

Sunlight is provided to the interior of the torus by a system of mirrors. The ring is connected to a hub via a number of "spokes", which serve as conduits for people and materials travelling to and from the hub. Since the hub is at the rotational axis of the station, it experiences the least artificial gravity and is the easiest location for spacecraft to dock. Zero-gravity industry is performed in a non-rotating module attached to the hub's axis.^[8]

The interior space of the torus itself is used as living space, and is large enough that a "natural" environment can be simulated; the torus appears similar to a long, narrow, straight glacial valley<sup>[9]

Found Here: http://en.wikipedia.org/wiki/Stanford_torus</sup>
whose ends curve upward and eventually meet overhead to form a complete circle. The population density is similar to a dense suburb, with part of the ring dedicated to agriculture and part to housing.

THE OVERALL SYSTEM

The focus of the system is a space habitat where 10,000 people work, raise families, and live out normal human lives. Figure 1-1.shows the wheel-like structure in which they live. This structure orbits the Earth in the same orbit as the Moon in a stable position that is equidistant from both Earth and Moon. This is called the Lagrangian libration point, L5. The habitat consists of a tube 130 m (427 ft) in diametral cross section bent into a wheel 1790 m (over 1 mi) in diameter. The people live in the ring-shaped tube which is connected by six large access routes (spokes) to a central hub where incoming spacecraft dock. These spokes are 15 m (48 ft) in diameter and provide entry and exit to the living and agricultural areas in the tubular region. To simulate Earth's normal gravity the entire habitat rotates at one revolution per minute about the central hub.

Much of the interior of the habitat is illuminated with natural sunshine. The Sun's rays in space are deflected by a large stationary mirror suspended directly over the hub. This mirror is inclined at 45 degrees to the axis of rotation and directs the light onto another set of mirrors which, in turn, reflect it into the interior of the habitat's tube through a set of louvered mirrors designed to admit light to the colony while acting as a baffle to stop cosmic radiation. With the help of abundant natural sunshine and controlled agriculture, the colonists are able to raise enough food for themselves on only 63 ha (156 acres). The large paddle-like structure below the hub is a radiator by which waste heat is carried away from the habitat.

Abundant solar energy and large amounts of matter from the Moon are keys to successfully establishing a community in space. Not only does the sunshine foster agriculture of unusual productivity, but also it provides energy for industries needed by the colony. Using solar energy to generate electricity and to power solar furnaces the colonists refine aluminum, titanium, and silicon from lunar ores shipped inexpensively into space. With these materials they are able to manufacture satellite solar power stations and new colonies. The power stations are placed in orbit around the Earth to which they deliver copious and valuable electrical energy. The economic value of these power stations will go far to justify the existence of the colony and the construction of more colonies.

Principal components of the overall space colonization system and their interrelations are shown schematically in figure 1-2.

DESIGN GOALS

This system is intended to meet a set of specific design goals established to guide the choice of the principal elements of a practicable colony in space. The main goal is to design a permanent community in space that is sufficiently productive to maintain itself, and to exploit actively the environment of space to an extent that permits growth, replication, and the eventual creation of much larger communities. This initial community is to be a first step in an expanding colonization of space.

To effect this main goal, the following subsidiary goals must be met using existing technology and at minimum cost:

1. Design a habitat to meet all the physiological requirements of a permanent population and to foster a viable social community.
2. Obtain an adequate supply of raw materials and provide the capability to process them.
3. Provide an adequate transport system to carry people, raw materials, and items of trade.
4. Develop commercial activity sufficient to attract capital and to produce goods and services for trade with Earth.

   Fortunately, the design study could draw on substantial earlier work. Active interest in space colonization as a practical possibility began in 1969 when Gerard O'Neill and students at Princeton University undertook a detailed assessment of space colonization. They aimed at a model to show the feasibility of a space colony rather than an optimum configuration and they selected as a test case a rotating habitat in satellite orbit around the Earth at the distance of the Moon, using solar energy to sustain a closed ecological system. They proposed a habitat constructed of processed lunar ore delivered by an electromagnetic accelerator and located at either the Lagrangian point L4 or L5 in order to make delivery of the ore as simple as possible. (The Lagrangian points are described in ch. 2.) The habitat was configured as a l-km long cylinder with hemispherical end-caps. It was to have an Earth-like internal environment on the inner surface and be supplied with sunlight reflected from mirrors (ref. 1).

   Subsequently, the Princeton group suggested that the L5 colony could construct solar power stations from lunar material. They concluded that this would improve the economics of both the satellite solar power stations and the colony itself (ref. 2).

   The concept of satellite solar power stations has received increasing attention since its introduction by Peter Glaser in 1968 (ref. 3). These ideas were further considered and developed by a conference "Space Manufacturing Facilities" which took place at Princeton University on May 7-9, 1975 and focused more attention on O'Neill's test case.

   This report presents a rationale for the design choices of the Ames-Stanford study group and it details how the various parts of the system interrelate and support each other. The next three chapters discuss successively how the properties of space specify the criteria that a successful design must satisfy, what human needs must be met if people are to live in space, and the characteristics of various alternative components of the design. Some readers may wish to skip directly to chapter 5 where the details of the operation of the system are described. Chapter 6 provides a detailed analysis of the sequence of events needed for the colony to be built. Timetables, manpower requirements, and levels of funding are presented for the construction of the main parts of the overall system. This chapter also looks at long-term benefits from solar power stations in space and some possible ways to structure economics so as to initiate the establishment and growth of many colonies over the long term. Chapter 7 looks at the future development of colonization of space, and finally chapter 8 discusses why space colonization may be desirable and provides some conclusions and recommendations for further activities and research.

Found Here: http://settlement.arc.nasa.gov/75SummerStudy/Chapt.1.html

Orbital Culture

In Iain M. Banks' fictional Culture universe, an Orbital (sometimes also simply called an O or a small ring) is a purpose-built space habitat forming a massive ring (though much smaller than a ringworld) rotating to simulate gravity.

Its inhabitants, often numbering many billions, live on the inside of the ring, where continent-sized 'plates' have been shaped to provide all sorts of natural environments and climates, often with the aim of producing especially spectacular results.

Structure

Banks has described Orbitals as looking like "a god's bracelet" hanging in outer space. Orbitals are ribbon-like hoops of a super-strong material (see also unobtainium) reinforced and joined with force fields. Each Orbital possesses a 'hub', a station suspended at its rotational centre which houses the Orbital's governing Mind.

An Orbital is similar to a ringworld but is much smaller and does not enclose its primary star within itself, instead orbiting the star in a more conventional manner, making it much more intrinsically stable than a ringworld. Many different civilizations are known to use Orbitals sized according to the preferences of the builders; the Culture's Orbitals are approximately ten million kilometres in circumference, which, together with their rotational speed, creates gravity and day-night cycles to normal Culture standard.Look to Windward - Banks, Iain M., Orbit, 2000, Page 275 They have widths varying between one thousand and six thousand kilometres, giving them a surface area of between 20 and 120 times that of the Earth (but comprising significanly less mass).Iain M. Banks,

Interior

The inside of the hoop can be formed to any type of planetary environment, from desert to oceanjungle to glacier. The structure is usually divided into individual 'plates', similar to continents. Though there need be no directly visible indication for the transition from one plate to another, on some Orbitals the border between neighboring plates is marked by an artificially high string of mountains known as a 'bulkhead range'. These also serve to contain the atmosphere in those areas where the Orbital may not yet be complete, with those gaps in the plate ring being bridged only by forcefields.

Some plates mimic natural environments very closely, others are wild exaggerations possible only by advanced matter forming and intricate (but usually hidden) machinery - such as a gigantic river circumnavigating the whole Orbital, which in some reaches travels on immense, kilometre-high bridge- or mountain-range-like constructions, and in other regions might act as an immense 'waterslide' for a floating event stadium.

Orbitals spin to mimic the effects of gravity and are sized so that the rate of rotation necessary to produce a comfortable gravity level is approximately equal to one day. In the case of the standard Culture day and gravity, this diameter is around three million kilometres (almost three times the diameter of Earth's Sun). By tilting the axis of the Orbital relative to its orbit around a star a convenient day-night cycle can be experienced by the inhabitants. Since the edges of the Orbital are built as high walls, the rotation prevents the atmosphere from escaping, thus protecting the inhabitants from radiation. The walls are typically tens or hundreds of kilometres high. to

Governance

Responsibility for day-to-day administration of one of the Culture's Orbitals and the management of its complex systems mainly rests with a Mind, which is situated in a structure in space at the centre of the Orbital, known as the Hub. The Mind is generally referred to simply as "Hub" by the inhabitants of the Orbitals, who never tend to be more than a millisecond away from the personalized contact and care it provides (via a contact terminal, usually worn as a piece of jewelry).

As the Hub Mind is extremely advanced, it could simultaneously hold conversations with every one of the billions of citizens a fully-settled Orbital has, and constantly controls millions of avatars, (usually) humanoid representatives of itself, throughout the world, though it can also interact in myriad other ways. It will also provide near-instant aid or material comforts, usually via service drones or matter displacement - being a near-omnipresent, omniscient as well as generally all-benevolent presence in the life of an Orbital citizen. As an insurance policy against unscrupulous Hub Minds, and to represent the community to visitors from more traditionally hierarchical societies, each Orbital also elects a body called a General Board from among its human and drone population. As a further check on the power of the Hub Mind, matters of public concern are decided by referendum.

Other civilizations also build Orbitals, however, and it is not clear if all are similarly managed.

Notwithstanding these advantages of Orbital life, Orbitals have been called 'backwaters' by some Culture citizens who prefer travelling lives.

Culture

The culture within the Orbitals is typical for the philosophic-hedonistic slant of all the Culture. They are also prime examples of the Culture's post-scarcity society, for within some physical limits, all material wishes can be fulfilled (or will be fulfilled by the Hub on request).

Orbital culture is thus heavy on enjoyment, arts and crafting, creative endeavours of all kinds, learning, as well as sports and games. The mere building of an Orbital is an adventure itself, in which the Hub mind involves its inhabitants; beginning with two plates orbiting its future Hub, with more plates added to them at regular intervals. The final joining plates may not be fully formed and 'landscaped' until after a very long time - at least as measured from the viewpoint of a biological member of the Culture.

While the number of people living on an Orbital tends to be in the many billions, the sheer size of the habitat, as well as the casual lifestyle of the Culture, ensure that it almost never feels crowded. Citizens can choose to withdraw into large areas of primal (if ultimately manufactured) nature or into their own spacious homesteads, and tend not to live in cities unless they prefer the increased activity and the proximity of friends.

Orbitals also serve as residences for 'Ambassadors' of other societies to the Culture - though as shown in some of the books, the Culture understands this term differently: the alien is fully intended to eventually consider the Culture superior to his own society and become an ambassador for the Culture.

Found Here: http://reference.findtarget.com/search/Orbital%20(The%20Culture)/

Orbital Space Settlements

Unlike astronauts in space stations, people will consider their orbital space colony home, although they may visit Earth from time to time. A colony is a place to live, work, play, raise a family, argue with the neighbors, and grow old in low-g comfort.

Since space colonies are for permanent living, not just a few month's work, they must be much larger. In this article we will discuss several space settlement designs, all include habitable areas a kilometer (nearly a mile) or more in size. This is much larger than the space stations described above, which are all a few tens of meters long at best. Thus, orbital space settlements are expected to be about 100 times larger than today's space stations.

Space stations have small crews, usually only a few people. Supplies of air, water, and food can be brought from the ground with limited recycling. The colony designs we examine here are for thousands of people, and this means there are a few minor problems to solve :-). For example, space has no air, no water, no food and it's way too difficult to bring enough up for thousands of people. In addition, in the sun it is far too hot and in the shade it's unbelievably cold. There's also quite a bit of radiation. All the great stuff the Earth provides more-or-less for free: air, water, reasonable temperatures, radiation protection, and even gravity need to be provided by the space colony.

The first priority is something to breathe. The colony must be filled with air and the hull (the outermost shell) must be air-tight. If the hull leaks much, the colony will lose its atmosphere and become unlivable. Since outside the hull is a vacuum, the atmosphere on the inside will push outwards on the hull, which must be strong enough to withstand the air pressure. At sea level on Earth air pressure is about ten tons for every square meter (roughly a square one yard on each side). However, people can breathe perfectly well in the mountains where the air pressure is much less, so less dense air pushing with six to seven tons per square meter should be adequate. Fortunately, we have been building small, air- tight spacecraft for over forty years now, we just need to make them bigger. Unfortunately, just being strong enough to hold the air in isn't enough. To get something resembling gravity we need to spin the colony and that puts even more stress on the hull.

Astronauts in the ISS don't weigh anything. They just float around, which is great fun. However, even though astronauts exercise for hours every day, weightlessness causes muscles and bones to atrophy. Our bodies only stay strong when they work, and removing the stress of Earthly gravity reduces the workload a great deal. Some astronauts become so weak they can't stand up when they get back to Earth.

No one has any idea what would happen to children raised in weightlessness, but it's a safe bet they will never visit Earth, even for an all-expense scholarship to Harvard. Without the stress placed on a growing body by Earth-normal gravity, bones and muscles will have no reason to develop strength and power. Fortunately, we can get something that feels a lot like gravity by rotating our colonies. This is called pseudo-gravity. Living in Earth-normal pseudo-gravity should allow adults to keep their strength and children to develop it. The need for pseudo-gravity puts additional stress on the hull, but, as luck would have it, we already know how to make materials that are plenty strong enough.

Currently available materials are perfectly adequate to build colonies up to a few kilometers across or so. This is about the size of a California beach town. A population of ten or twenty thousand will fit quite nicely. Credible designs even exist for colonies many tens of kilometers across with populations in the millions, but the first colonies will almost certainly be smaller.

Orbital space colonies can come in many sizes, but the need to rotate to get pseudo-gravity means that only a few shapes work really well. Specifically: balls, cans and donuts; more formally called spheres, cylinders, and toruses. It's also possible to combine shapes; for example, you can attach many toruses together - like stacking donuts - to get a colony shape called the 'crystal palace'. Each shape has its advantages and disadvantages and different groups of colonists may be expected to choose different shapes depending on their needs and desires.

The simplest shape is the ball or sphere. This has the advantage of having the minimum surface for any fixed volume. This is an advantage because the exterior must stop the radiation so common in space. The simplest way to stop the radiation is just to pile enormous amounts of material, anything will do, on the outside. You need roughly five tons for every square meter of surface. Since the sphere has the smallest surface area for whatever volume one needs, the amount of radiation shielding is minimized. Since all the shielding must be imported from the Moon or NEOs, this can save a lot of work.

NEO stands for Near Earth Object. NEOs are asteroids and comets that pass near Earth. There are about a thousand of these one kilometer across or bigger, and many millions of smaller ones. Some NEOs are actually easier to get to than the Moon, so they may be a great source of materials.

Note: this section includes 3D models of space colonies that you can view if you have a VRML plugin for your web browser. One such plugin is the Cortona VRML Client, which is free. All the VRML for this page was produced by Nittin Arora and Ankur Bajoria.

Stanford Torus

A second popular shape for space colonies is the donut shape, also called a torus. The torus shape is popular with movies and television shows; for example, the space station in the movie "2001 - A Space Odyssey" and the TV show "Star Trek: Deep Space Nine." The best developed toroidal colony design is the Stanford Torus (click here for 3D VRML model of two Stanford Toruses). The Stanford Torus has a diameter of about a mile and rotates roughly once per minute. It features a large mirror to reflect natural sunlight into the colony. There is also a sphere in the center for weightless recreation and light industry. Click on the thumbnails for larger drawings of the Stanford Torus.

Toroidal space colonies have some advantages. The whole outside of the donut rim is about the same distance from the axis of rotation so there's lots of 1g living area. Since the main living area curves, you can't see the whole colony from any place in the interior. Some people think this is a psychological advantage.

There are disadvantages as well. First of all, there is far more surface area than other shapes, so much more radiation shielding is needed. This substantially increases the mass. Also, a simple torus has no livable space in the center where you can have weightless recreation. This is a big one. Remember that the pseudo-gravity you feel depends on how far from the axis of rotation you are. The further away, the more you weigh; the closer the less. Right at the center you don't weigh anything at all - just as if there was no rotation. Since one of the great things about living on a space colony is weightless recreation, a simple torus is not a viable approach. Most toroidal orbital colony proposals feature spheres or cylinders at the center to provide 0g fun for the inhabitants. This however, increases the surface area of the colony even more, which requires more radiation shielding.

Found Here: http://space.alglobus.net/Basics/what.html