7. Internal Design

There is inevitably a certain amount of number crunching involved in decisions about internal design.  Although presented here as the seventh section, the first step of the project was really to research and decide on definite areas for residential areas, agriculture, recreation, services, industry and research within the settlement.  These figures have already been given whilst detailing the choice of External Design, however this section will now deal with how this space is allocated on the interior DL4, specifically deciding on facilities requiring less than 1g and others that need normal gravity.  The sections following will give details of the allocation of space within each area and the use that this space will be put to.

7.1        Low Gravity Levels

As one of the main attractions of DaedalusaL4 to both industrial and research groups as well as residents will be the availability of facilities at less than 1g it is important to provide sufficient area for these.  It was decided that, for the resident’s use, 5,000m² (equivalent floor space) of recreational space was needed in a micro/zero-g environment, while 60,000m² and 9,000m² were required for industry and research respectively at low gravity levels. The 113,332m² allocated to services in low gravity contains all life support systems along with the power receiving and heat radiating equipment found within the central sphere.  Additionally, it includes the area needed for power distribution but it mainly consists of floor space needed for docking facilities (area » 111,332m²).  It was, however, not possible to include the total possible floor area of the spokes, which are, of course, totally devoted to the services of transport and their own maintenance.  Therefore, an area of 616m² was included both within the low gravity and normal gravity levels for the floor area of the lifts (across four spokes).  With this in mind the central sphere and moveable spheres were internally adapted for such usage. 

Central Sphere

Internal pre-planning of the central sphere is limited, with the exception of the previously mentioned provision of docking facilities, rectenna/thermal radiators and windows.  The docking facilities will be housed within a cylinder on the lower hub of the sphere.  This will have an approximate floor area of 111,332m², with it’s base starting 111.7m from the sphere’s centre and extending out for a further 188.3m (15m of which is beyond the sphere’s walls) at a radius of 94.1m (see fig. 7.1a).

Removing the area required for these facilities we are left with approximately 65,134.9m² of floor space within acceptable gravity levels (usable by industry while still providing sufficient weight to humans to allow their movement throughout the area).  The diminished gravity in this area (varying between 0.32g and 0.29g) allows for the easy production and transport of heavy industrial products around the sphere and into the docking facilities for external construction of satellites (especially SPSs).  For this reason the total usable floor area on the inside of the outer wall of the central sphere has been devoted to industry.

Within the central sphere two additional inflatable spheres are found within each other at the heart of DL4. While the innermost 40m radius sphere contains the micro/zero-g recreation area and the required 5,000m² equivalent floor space, the outer, 55m radius, sphere contains the lowest gravity level for research (see fig. 7.1a).  Of course, given the attraction of micro/zero-g to industry and research as well as residents there will have to be some sharing between the two groups of these spheres.  However, the design of the main central (300m radius) sphere allows for industries to avail of micro/zero-g conditions outside of the innermost spheres along the axis of rotation and below the acceptable gravity area of the central (300m) sphere.  Meanwhile the window area of the sphere, located outside the usable gravity level, offers the only vantage point from the settlement to outside objects (the torus windows and lower central sphere windows being blocked by the mirror and other sections of the settlement).  Therefore a small upper three metre band of transparent glass will be provided, with a suitable floor at the top of the window.  However, this ‘observation deck’ will be at such a low gravity so as to make the floor basically redundant.  Hence, it will mainly be used as a lift access point and safety net from the industries below.  The fact that this area is at such a low gravity enables residents to view while effectively floating, hence removing them from the spinning motion of the settlement and allowing them to look out one section of the window for an indefinite period of time.  This deck adds an extra 1,000m² to the required recreational area at low gravity but does not affect any other areas in the central sphere as it is so far out of the acceptable gravity and usable areas thanks to the large windows.

Moveable Spheres

The moveable spheres various floor levels will be totally handed over to research groups.  These will be best able to avail of the variable gravity levels attainable by moving the spheres up or down the spokes.  Within the spheres themselves three floors will be provided to allow extra space for equipment storage.  The lowermost floor, 1, will be approximately 19.5m from the centre of the sphere while the other floors, 2 and 3, are located 18m and 36m respectively above this  (see fig. 7.1b).  (This gives both floors 1 and 2 ceiling heights of 18m while floor 3 has a maximum height of 5.5m, which decreases with an increase in radius.)  The placing of the 3m high doors on each floor level thus allows all three floors to be docked at access ports to the lift shaft at the same time when the sphere is at rest (as access points have been provided every 18m in the spokes).  Additionally, this plan gives floor 1 an area of about 239.35m² (radius » 10.19m), while floors 2 and 3 have areas of 1,426.87m² (radius » 21.95m) and 578.64m² (radius » 14.55m) respectively.  (These figures take into account the 3m loss of radius in the spheres due to radiation shielding and the 86.59m² loss of area due to the ‘sleeves’ running through their centre.)  Over the four spheres these areas add up to 8,979.44m², so with the addition of a small area on the central sphere’s wall and a large area within the micro/zero-g spheres and along the axis of rotation, DL4 will easily accommodate the 9,000m² that is required at low gravity levels for research.

7.2        Area at 1g

Torus

As detailed in 2, External Design, the torus was designed to accommodate a single floor around its internal diameter, parallel to the axis of rotation.  This means that the torus will have no variable gravity levels, instead, thanks to our rotation rate of 0.975rpm and radius (to the floor level) of 941m, maintaining a constant 1g pseudogravity.  Therefore residential areas accommodating all the population of the settlement will occupy the majority of the torus.  However, additional facilities will also be required if the torus is to be put to such usage. Recreation and service areas will be needed as well as all of agriculture and some industry (mainly devoted to the manufacture of goods required by residents, e.g. - cotton, linen, plastics – see 11 Industry) and research.  The following figures were decided upon for the allocation of floor space within the torus.

table 7.2a - required floor area within the torus

As in 2, External Design, the torus was given a minor radius of 125m (minus 3m radiation shielding), a circumference of 5,912.47m and therefore a floor area of 1,442,642.68m², DaedalusaL4 can easily accommodate the required torus surface area.

A brief discussion of the various types of land usage would now seem appropriate (longer descriptions of these areas are provided in the following sections).

·         Residential area is quite self-explanatory, this represents the area used for housing and includes space for the residents to sleep, relax and eat their meals etc. (Note this is the actual floor area and does not take account of multiple floors within buildings.) The residential figure also includes area for private gardens (we would recommend roof gardens) which residents can cultivate if they so wish.

·         Recreational area provides space for people to relax, socialise and exercise.

·         Agriculture is the area housing food growth facilities for the residents.

·         Industrial area refers to the area used for activities such as materials processing for the residents. This figure does not include the area used for the construction of solar power satellites as this is housed in the central sphere.

·         Finally, services refers to all the multitudinous things needed to keep the station functioning, electricity distribution systems, mechanical sub-systems, life support devices, preliminary food processing, and entrances to the transport network. This figure also includes the area used for commercial premises, schools and other education facilities and hospitals.

Now that we know how much space is required for each purpose, the next question is exactly how to distribute it. For this, the torus was divided into four quadrants. Each quadrant is further subdivided into two distinct sections one industrially orientated, the other agriculturally orientated. While it was considered grouping all the agriculture together and likewise all the industry this strategy was, after much research discounted. There are several reasons for this. Firstly there is the issue of safety and redundancy, i.e. if one of the areas containing agriculture was to become unusable then the residents could survive on the produce from the other three areas until such a time as repairs could be completed. If there was just a single agricultural area, this would not be possible. Additionally, it makes it easier to separate the agricultural area so four distinct seasons can be created. A single large area would also be more susceptible to crop failure. Finally, it is desirable to have the agricultural areas located somewhat close to industrial areas to facilitate the easy processing of crop derived products such as cotton, linen (from flax) and soy bean plastics, while at the same time not locating factories directly beside the crops.

The tables below illustrate the distribution of the different types of land use within a quadrant.

tables 7.2b and 7.2c – Allocation of space within Sections 1 and 2 of each quadrant

From these figures, each section 1 will be able to accommodate 800 people while 1,700 can be housed in each section 2. The figure for services is greater per head in section 1, due to the location of food processing facilities in close proximity to the agricultural area.  As mentioned previously, for the low gravity levels, services includes an area of 616m² for the floor area of the lifts.  Clearly, as there are four lift-containing spokes, there will be one per quadrant. Access facilities to these will be provided on the division between the two sections of each quadrant (i.e. – at the emergence point of the lift shaft).

For the purposes of safety onboard DaedalusaL4 the segmentation described above will not only be geographical but will also represent the location of physical divides within the torus.  The main divisions will occur between the quadrants where walls, although not totally sealing one quadrant off from the next, will extend a significant distance from the ‘roof’ to about 30m off floor level.  This gap is intended for the easy movement of goods and people between the areas and to help prevent Shimanagashi Syndrome (see 18 Health Care) caused by a feeling of isolation.  The 30 metres will however be easily closed with large doors, capable of dropping from the upper division in case of depressurisation of one of the quadrants or a large-scale fire.

There will also be the additional capability of segmentation between the sections of the quadrants, where in the case of less dire circumstances (not requiring immediate sealing), walls can be put in place.  This capability will merely consist of planned building layouts along the divide enabling the fast and effective construction of a protective bulkhead.  The inclusion of the lift shafts on the division line will provide a type of scaffold and aid the speedy construction of any such divide.  Beneath the ‘floorboards’ of the torus at every division, be it a quadrant or section, physical divides will be put in place during construction.

The floor itself deserves some mention.  This will be constructed from about 20m below the internal diameter of the torus (i.e. - 20m below the actual floor level, 961m from the centre of DL4), using extremely strong asteroid nickel reinforced aluminium beams.  This strength will be required as, below recreational areas the struts must support a large cubic volume (about 1,875,000m³) of soil to facilitate the growth of plants, specifically trees, while below more industrial or residential areas the floor must house underground water reservoirs for the storage of approximately 478,318.3m³ of water (discussed in 17.6 Water Processing).  The water (as discussed later) will be taken from the Moon, however, the soil may represent an additional large mass material needed to be sourced from Earth.  It would be hoped however, that with the addition of certain terrestrial minerals and humus to a lunar or asteroid ‘soil’ matrix, some of this mass could prove unnecessary.

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