Category Archives: O’Neill Cylinders

Bicycle sharing

Earlier we discussed the use of personal rapid transportation or PRT in space settlements, and O’Neill cylinders in particular. In a previous post we proposed that the public transport system of a O’Neill cylinder would consist of:

1. A maglev metro along the heart line of the valleys, serving as the backbone of the transportation system;

2. A PRT network serving as a secondary network, aimed at short distance transport.

A question one could reasonable ask is whether having both systems is actually necessary? One could argue that an extensive PRT system would make the maglev metro obsolete.

In a smaller space habitat such as Stanford torus or Bernal sphere, having these two system would indeed be superfluous. The the distances within the settlement are too short. However, in greater settlements, such as O’Neill cylinders, there will be a differentiation between short and long distance travel. The longer the length of an O’Neill cylinder, the greater the justification for a dual transport system.

PRT systems are usually designed to travel at speed 40 to 50 km/h, while maglev trains in vacuum could easily reach 8,000 km/h.

It might take several decades to complete an extensive PRT network (a maglev metro needs to build during the construction of the space habitat). Hence we need to consider an alternative transport system.

Again we suggest to use the maglev metro as the backbone of the public transport system. Additionally there will be a bicycle sharing system, which would allow people to travel to and from the maglev station.

In a bicycle sharing system people can use publicly owned bicycles against a low or even zero price. One takes a bike from station A and go to station B and leaves the bike there.

There are many methods to prevent people from stealing these public bikes. The system as we propose, is the following. First public bikes will be of an unusual model, to make a clear distinction between privately owned bikes and public bikes. Further bikes will be locked at their station and only be taken after paying a refundable deposit, for which people need to buy a special coin. The coin is returned once the user brings the bike to a public bike station.

The requirement to buy a special coin, rather than to use normal coins, will allow the operator to charge a higher price for the use of public bikes. This would create a greater deterrence for potential thieves as well providing some revenue to fund the program.

A bicycle sharing system could be extended to include tandems and freight bikes as well. The bikes could also be provided with an electric support motor.

Public transportation in O’Neill cylinders

In a previous post I discussed the spatial planning of the interior of O’Neill Cylinders. In a note I promised to make another post about (public) transportation inside O’Neill cylinders. For the sake of the argument, I will assume here that the chosen spatial planning is either the Broadacre cityGarden city or Colombia design. Further I want to recall that a O’Neill cylinders has a length of approximately 35 kilometers and a diameter of 6 kilometers (specific dimension may vary among different sources, however the difference is usually only a few kilometers).

A key feature of the design of the O’Neill cylinder is the alternating arrangement of “valleys” (stripes of land) and windows, three of each. It follows from the given dimension that each valley is approximately 3 kilometers wide and 35 kilometers long. Gerard O’Neill himself proposed that there would be parallel to the valley’s heartline a subterranean maglev line. This would function like most subway systems on Earth and would enable (long distance) rapid transit in an O’Neill cylinder. However this system, would not quite suitable for short distance travel, therefore a second transportation system is required.

While the maglev subway will serve as the core of the framework of intra-habitat transportation, there will be finer second network. What requirements do we look for? Ideally we would like an on-demand service, great amount of privacy and the ability to choose our destination. However do not like to waste a lot of time for searching for parking lots. Personal Rapid Transit (PRT) is a proposed idea which would combine the best of private and public transportation.

In order to show what a PRT system might look like, I have selected two YouTube videos about personal rapid transit systems. The first YouTube video (of 8.45 minutes) is about the personal rapid systems as designed by Swedish company Vectus.

This second YouTube video (5.55 min) is a promotional video of Vectus, in which they explain how their product will work.

Yes, I do realise that Vectus is a commercial company which seeks to sell its concepts. Nevertheless, I think that this “sales man videos” give a clear picture how PRT systems would operate in practice.

The prospects of personal rapid transit systems are bright. They will enable to establish the first car-free society in history without sacrificing the individual freedom of movement.

O’Neill Cylinders and spatial planning

This post was originally posted on on October 18, 2012

In an earlier post I discussed the potential of Bernal spheres and Stanford tori for city states, in this posting I will discuss several ideas for the spatial planning of O’Neill cylinders.

The ideas I will discuss here are not developed for space colonization as such, but can nevertheless be very inspiring for Space settlers. Especially for the larger space habitats spatial planning is an important topic. In this post I will discuss three proposals: O’Neill’s own idea, Ebenezer Howard’s garden cities and the ideas of Frank Lloyd Wright. The purpose of this post is not to force a certain spatial plan on to Space colonies, but rather to provide a framework for developing better societies.

Since O’Neill cylinders provide a large plot of usable land, they allows for more sophisticated spatial planning then smaller habitats. The latter will typically be highly populated and most of their usable land will be used for housing and closely related activities. Consequently the smaller habitats will lack any significant amount of nature (forests for example), while many, if not most, people will appreciate nature.

Since the days of O’Neill, the consensus among space colonization advocates (and we follow this) is that industry, agriculture and living should be separated (the first two should not be located inside space habitats), this is an important difference with terrestrial spatial planning. Combined with the practically unlimited resources in space, we are free to design the interior of an O’Neill cylinder as we like.

In his book, The high frontier, O’Neill has given an example of spatial planning. In chapter 5 he describes the build cities at the ends of each stroke of land, referred to as “valleys”, and using the land areas it self for villages, forests and parks.

It would be interesting to look at a few spatial planning concepts from the past. In the 1930s the American architect Frank Lloyd Wright  designed his famous Broadacre City. In this proposal “true” cities would disappear, while people would spread out over the country (for this reason his plan was not very popular outside the USA). One feature of this scheme was that each family receives a 4,000 square meter plot of land [1]. Which was to be developed according to wishes of the receiving family. While there many really good aspects to his vision, there is some important critique about the Broadacre City idea, which can be found here. A serious drawback of the original design is that it heavily depends on automobiles for transportation. In a space based nation, in which people are spread over many different space habitats, cars are really cumbersome to handle. As O’Neill explained the main modes of transportation in and between space habitats are space ships, maglevs, bicycles and walking [2].

My personal favorite is, however, the garden city, a concept developed by Ebenezer Howard around 1900. In short this urban design is an attempt to reconcile the city and the countryside. In Howard’s plan a garden city should require 6000 acres of land (which is approximately 25 square kilometers or 2428.2 hectare), of which 1000 acres are used for the actual city and the other 5000 acres are destined for agriculture [3]. As I have already said, most space habitat advocates favor a physical separation of agricultural and living areas. At first sight Howard’s idea seems to be outdated, and it is to some degree. Nevertheless I believe that this garden city concept is good starting point for our own spatial plans. We should look for alternative destination for these agricultural lands, a portion can be reserved for allotment gardens, while another portion is reserved for sport associations (think about field hockey clubs, rugby clubs and so on). In Howard’s original designs there is a remarkable lack of recreation areas (to be fair Howard planned a park in the center of his city, but this is one is to small for serious sport practice.)

The actual city itself, would be an annulus around this central park and would be divided into six wards, each with 5,000 inhabitants. This would give a total city population of 30,000 thousand, in addition a further 2,000 would live in the rural area of the city. Howard also thought about what to do when the city population would grow, unlike the natural course of urban growth by which new buildings are attached to the existing settlement, he foresaw to build new garden cities a few miles away of the old one. In fact he suggested to build a central city, a garden city with 55,000 inhabitants, first  and later to build six (normal) garden cities around it. The central city would serve as a regional center. This particular configuration is not feasible for a standard O’Neill Cylinder (diameter 6.4 km and length 32 km), but is we would increase these dimension s with a factor 5 (which would give an areal increase of a factor 25) then it would become an interesting option. However such O’Neill cylinders XL will not be realized in early space colonization.

A different but related concept is Columbia, Maryland. Like the conglomeration of garden cities, the different villages of Columbia are not one single area but separated by green areas (called the Tivoli garden). The city’s 100,000 residents [4] are spread among nine villages, with a land area of 82.7 square kilometers (compare this with a valley of 107.23 square kilometers). If we would organize a valley in a similar fashion as Columbia, than we would get a city with population of between 130,000 and 143,000 [5]. In order to keep this city mostly car-free, they designers envisioned a minibus-network.

As I have said at the beginning of this post, the purpose of the mentioned examples is to inspire the spatial planners of O’Neill cylinders. And I hope they will not make the same mistakes as those made by terrestrial urban planners. Space colonization is a nice occasion to experiment with innovation on spatial planning. Of course the specific spatial plans will depend on the political choices made by the owners/governments of space habitats, different political ideologies require different spatial plans. The examples I selected here, reflect my personal believes about decentralized republicanism with its preference for small non-urban communities as the framework for active citizens participation in public affairs.


[1] A valley of a typical O’Neill cylinder is 3.35 by 32 kilometers, which is 107.2 million square meters. And using Wrights 4,000 square meters per family, we can calculate that a valley provides land for 26,800 families.

[2] I will discuss transportation in space colonies more deeply in another post.

[3] Using the standard dimensions of a O’Neill Cylinder (length 32 km, diameter 6.4 km), we can calculate that each valley can host 4.4 garden cities. This gives a total population of 141,000 people for each valley (4.4×32,000).

[4] Originally (in 1966) it was estimated that Columbia would have 110,000 residents in 1980.

[5] The lower estimate is based on Columbia’s current population, the higher one the estimate from note [4].