Transfer Grid

This is the highest level you can reach in Grey Sector.  As you drift in the near-zero gravity, you see ahead the slowly-rotating concentric rings of the Transfer Grid, passing into the zero-gravity zone.  Maintenance Techs are bringing some large containers through as you watch, gaining weight as they pass into the rotating zone.  You are curious about what might be found here.

Locating the Sectors on Babylon 5

Here on Grey 1, we describe where the different colour-coded Sectors on Babylon 5 are situated.  The sector map shown below is the version on which we finally settled as the most sensible and self-consistent topology for the station (please visit Grey 17 to find out more about the delightfully impossible topologies that resulted from inconsistencies in the source material).  Broadly speaking, we have tried to determine each colour-coded sector as a distinct zone.  The alternative would have been to consider a patchwork of different locations, which might possibly interleave the different sector colours, according to the area's function.  Most sources [PoD, Inf, SM, RPG] (apart from [SH]) do not show zones penetrating each other.  References to our sources are given at the end of this article.

The Location of Blue Sector

Blue Sector contains C&C, the main docking entrance and bays, together with Babylon 5 Customs processing arrivals and departures, all military areas including fighter pilot's ready-rooms and the Cobra Bays housing the Starfury fighters, all accommodation for station personnel and some command staff offices. Areas such as the Observation Dome, the Sanctuary, the main Station House and at least one Medlab are situated in Blue Sector.

Blue Sector extends from the Command Sphere, through the Core and Cobra Bay arms to the Torus [SH, SM], or at least this far.  If sources [SH, SM, RPG] are correct, the boundary between Blue and Red Sectors is where the Torus joins onto the main Carousel.  If source [PoD] is to be believed, Blue Sector would extend into the Carousel, occuping half of the northern wide segment.  Other considerations for the space needs of Red Sector would seem to rule this out.  The extent described in [SH, SM] is therefore about right.

Issues of interest in Blue Sector include the siting of the Commander's Office and Medlab.  During the production of the TV shows, Medlab underwent a major rebuild at one point; this was explained as re-siting the facility in order to expand it.  The Medlab we see in season 1 and 2 was located in Blue Sector.  Some sources, such as [SM], cite up to 6 MedLabs on Babylon 5; this is corroborated by some TV shows in which Franklin adds digits (2, 5) to the names of different Medlabs.  JMS in his UseNet postings has said that there are several hospitals on Babylon 5, but that Medlab, especially the Isolab, is Franklin's private research facility.  Here, we site Medlab One in Blue Sector, and make it Franklin's xenobiological research centre.

Commander Sinclair's Office appears to be in Blue Sector from the coloured stripe in the corridor outside.  Sinclair's office is sparse, open-plan, with no doors to exclude visitors.  Source [WP] suggests that it is located on Blue 5 (this is where Sinclair agrees to meet all parties after the young Centauri couple are assaulted by xenophobic humans - this meeting happens in his office).  Circumstantial evidence from [BAMN] has Sinclair appear on Blue 6 shortly after a trade union meeting in his office.  We have adopted Blue 5 as the more secure location.  In later seasons, Sheridan's office looks similar but also has a view from a high vantage point out over the garden, which eventually sites this in Green Sector, which also follows [SM].

The Location of Red Sector

Red Sector is repeatedly referred to as the main commercial area.  It offers rented accommodation; for example, when G'Kar loses his ambassadorial status, he is forced to move to Red Sector.  It contains the open market, the Zocalo (Red 5) which runs in a ring around a major corridor.  It contains clubs, such as the Dark Star, Happy Daze and Doug's Dugout Sports bar.  It contains the Casino, which branches off the Zocalo.  It contains private rooms for commercial transactions, especially involving the hire of commercial telepaths.

Most sources [SH, PoD, SM] locate Red Sector in the northern, wide part of the Carousel.  This is where [RPG] also sites its "commercial zone", although this is incorrectly designated Brown Sector.  Having Red Sector contiguous with Blue Sector makes sense, since this allows paying visitors and traders to have immediate access to the commercial parts of the station.  The extent of Red Sector is harder to determine.  Source [SH] has it occupy the whole of the north end of the Carousel.  Source [PoD] has it occupy only half of this wide segment.  Source [SM] has it occupy most of the same segment, with a thin slice devoted to Green Sector.  The latter is so that diplomatic quarters may more easily be placed on many levels, overlooking the garden.  For a long time, we were persuaded by this argument, but eventually relocated the ambassadorial residences to a different site.

Episode [aSitW] features Amanda Carter renting a hotel suite 15 on Red 7.  Her rooms have a bay window overlooking the open part of the Carousel.  For this reason, we presume that hotel accommodation is located throughout the closed end of Red Sector, with views into the garden.  Therefore, Red Sector must occupy the whole of the built-up northern end of the Carousel.  This is more satisfying than [PoD], where the thin band of red would only account for the market and shopping areas and is not large enough to include commercial accommodation.  Alternatively, rented suites could be scattered throughout Babylon 5, especially in unclassified parts of the garden area.  However, this is unlikely, since we never hear of a station location that is not referred to by some colour-code.

The Location of Green Sector

Green Sector is the area reserved for ambassadors, diplomats and their related staff.  It is a high-security area, protected from general public access.  According to the schematic displayed on a BabCom terminal in [PoD], Green Sector occupies only the middle segment of the main Carousel, where the diameter of the Carousel widens somewhat.  The rest of the open garden is unclassified.  By contrast, sources [SH, SM, RPG] classify all of the interior space of the station by some colour-code (although [RPG] is wrong in assigning the southern half of the garden to Red Sector).  On the initial issue of whether to include or exclude the garden from Green Sector, we decided to include it, because of the obvious ecological resonances.

Much harder to decide is the extent of Green Sector.  The greatest extent is proposed in [SM], where Green Sector occupies a slice of the closed northern end, the whole of the open garden and most of the closed southern end of the Carousel.  The main concern here seems to be to offer all of the possible gravity environments to visiting aliens.  The ambassadors are housed in the north, while the alien quarter is situated in the south [SM].  We know that the aim is to provide rooms on multiple levels, to offer different simulated gravities and supply different atmospheres, such as methane or carbon dioxide.  We see that Ambassador Kosh's quarters have such an environment in Green 2.  It is therefore tempting to associate the alien quarter with Green Sector.  However, JMS has suggested in his UseNet postings that the alien sector and diplomatic areas are quite distinct; that the diplomats have their own alternative environments.

Originally, we were persuaded by arguments that the ambassadorial wing of the station had to provide all possible gravity environments.  On closer inspection of the TV shows, it seems clear that all of the major alien ambassadors to Babylon 5 have their apartments on Green 2!  Kosh's environment is on Green 2 [MotFL], as is Londo's suite [BttP], Delenn's suite [tWP] and G'Kar's suite [Sur]; but Kosh is later on Green 23 [aNfaW].  The view from Mollari's quarters is a moderately high perspective down onto the open garden, with assorted buildings below.  This would place him a few storeys above ground level, no more than 10-20 floors up.  If we assume that the levels are numbered outwards from the core of the station towards the hull, then the only level above Green 2 is Green 1, and all above this must be open to the core.

Happily, this coincides with the view from the Core Shuttle [TG].  This image shows a high view down onto a moderately built-up area situated about halfway along the garden.  Similar views show that Babylon 5 has a partially built-up area roughly where [PoD] suggests the ambassadorial wing is to be found.  However, this area is not built up very high, since views past Sheridan's office to the end of the Carousel are not significantly obstructed by any central plug [tGoS, MfE].  So, we choose to site the diplomatic quarter in the middle of the Carousel, according to [PoD].  Alien diplomats may benefit from gravities ranging from about 0.7g to 1.3g in the enlarged middle hull section, which seems adequate for humanoid species.

Issues of interest in Green Sector include how long the open part of the garden is; and the siting of Captain Sheridan's office.  Many views along the open length of the Carousel show at least three sets of pillars [tGoS, MfE, WP].  Exactly three sets of pillars are given in the sectional schematic of [SM].  However, the pilot [TG] has at least four sets of pillars.  It is important that Green Sector has at least one set of Transport Tube elevators, which must either be centrally sited, or some distance from the diplomatic quarter.  The former is easier to assume, meaning that the Carousel has either three (minimum) or five (maximum) sets of supporting pillars.  From the closing episode [SiL], the exploding Carousel seems to be open up to the widest sections at the ends.  This coincides with the schematic in [SM]. We assume that the central 2km of the Carousel is open, while the wider end sections are fully built-up, plugging the ends of the Carousel.  This means that Blue Sector cannot overlook the open garden, whereas Red Sector apartments may do so.

Sheridan's office in the later seasons is not the same place as Sinclair's office in season one.  It has a side-facing view down onto the curving surface of the garden, in a moderately built up area.  When the camera pulls back in external shots [tGoS, MfE], it seems that the office is somewhere in the open garden, with several sets of pillars receding to the end plug.  This places the office clearly in Green Sector.  The Babylon 5 Security Manual sites an administration complex in the northern half of the garden [SM], which is consistent with this.  The blue stripe outside his doorway is then either an inconsistency, or a nominal colouring, in the same way that all embassies are treated as foreign soil!

The Location of Grey Sector

Grey Sector is the heavy engineering industrial zone, where construction and manufacturing are carried out by Babylon 5 station personnel.  Parts of Grey Sector are more finished than others, which seem to consist of zones that can be sealed off behind bulkheads.  Various station services pass through Grey Sector, such as the coolant pumps for the fusion reactor [CoLaD] and power distribution conduits [GiM].  Grey Sector has up to 30 levels, when travelling by tube elevator [GiM]. This evidence puts Grey Sector close to the fusion reactor, in a section where the rotating part of the station has a narrower diameter than elsewhere.

Grey Sector must be situated to the rear of the Carousel, between the main habitable parts (since it is under gravity) and the uninhabited parts reserved for the Fusion Reactor (since the reactor cooling system is mentioned) and its associated services.  The fact that Grey Sector has only 30 levels which are under gravity is also significant.  If you estimate a deck spacing of 3-4 meters (to accommodate humanoids of 1.8m, headroom and decking), then this corresponds to about 90-120m of the internal radius of the station, meaning that Grey Sector is ideally either a ring with a hollow centre, or a cylinder with a narrower diameter.

[SM] has Grey Sector extend from the last quarter of the southern wide segment of the Carousel and through the Collar section which supports both the Spine and the solar arrays.  The longitudinal cutaway section on p14-15 shows the rotating part of Grey Sector as tapering into the non-rotating part, with maglev bearings to support the Carousel.  This is consistent with the fewer decks of Grey Sector than some other sectors (Grey Sector has only 30 levels, whereas Brown Sector has at least 95 levels).  According to [SM], Grey Sector has transfer points between the rotating and non-rotating parts of the station, which is also plausible.  It is therefore most convincing to imagine Grey Sector as having a narrower diameter and being at least partly embedded inside the non-rotating part of the station.

Other sources are less convincing.  The schematic shown in [PoD] did not display Grey Sector, which was plausibly concealed behind the heat exchangers/solar arrays, as revealed by the exploded schematic in the episode [HP].  Similarly, the schematic in [SH] appears to site Grey Sector in the northern half of the Carousel's southern wide section.  We discount these on the grounds that Grey Sector would then have at least 95 levels.  It is more satisfactory if Brown Sector occupies this location, since it is the residential quarter for aliens with different environmental needs.  Siting Brown Sector to the north means that aliens may have suites overlooking the garden, in a mirror-image of Red Sector.  Grey Sector is devoted to heavy engineering, so needs no such vistas.

The less-reliable source [RPG] sites the beginning of Grey Sector in much the same place as [SM] but extends the grey colouring to the reactor cooling fins.  This is implausible, since over half of Grey Sector would have to be under zero gravity.  It is also inconsistent with [SH, PoD], which display the whole 2.6km length of the reactor complex in yellow (or possibly with brown incursions, in [PoD]).

From these considerations, we prefer Grey Sector to occupy the narrower cylindrical section at the southern end of the Carousel, extending south in a tapering fashion into the non-rotating part of the station, approximately up to the start of the reactor cooling fins.  This is similar to [SM], but displaced slightly southwards. We do not think that Grey Sector can include the wide part of the Carousel, because of the few levels it contains.  We think that it must extend further south than in [SM], so that it is contiguous with the reactor cooling system (in Yellow Sector).  The cooling system itself cannot be in the rotating part of Grey Sector - this would serve no purpose, requiring complex arrangements for fluid transfers, but Grey Sector must be physically close to the cooling system for the noise of the pumps to transmit through the superstructure [CoLaD].

The Location of Brown Sector

Brown Sector is referred to as a service area of the station, containing water recyclers and waste reclamation units.  Brown Sector appears to consist of at least some regular corridors and appartments [MotFL, BttP, tGoS].  It also seems to be the site of "Downbelow", the unfinished hull area of the station that was deliberately left undeveloped and so became colonised by vagrants, unfortunates and criminals, collectively known as Lurkers.  We also find a number of alien species living in Brown Sector, in proximity to the recyclers, either because they are carrion eaters, or they cope better with the bad smells.

Brown Sector must at least contain "Downbelow".  In one source [SM], Brown Sector is not listed as a bona fide zone.  Instead, "Downbelow" and waste recycling units are shown at various points between the inner and outer skins of the Carousel (see [SM], p14-15), making you think that Brown Sector is possibly not a section of the station, but rather the whole envelope between the inner and outer hulls.  It would be plausible for waste reclamation to be sited here, since simulated gravity would cause waste matter to drain towards the station's circumference.  When lurkers are seen to peer through viewports in the outer hull [tLD], this confirms the location of "Downbelow" as the hull area.  In the TV shows, "Downbelow" is also indicated when pointing to non-brown coloured areas, such as when the crew are tracking the Ikarran war machine on "Brown 2, level C", while pointing to the northern half of the garden [Inf].  For this reason, we believe that Brown Sector must include the outer hull layers of the Carousel, for its full length.  We believe from other evidence that there are three such hull levels (visit Grey 3 to discover this).

However, Brown Sector must consist of more than "Downbelow", because there are at least 95 levels altogether, from Corwin's warning of a fighter attack on the hull in [SD].  Aliens such as N'Grath live as high up as Brown 9 [MotFL, S] and a dancer shares her quarters in Brown 6 with Adira Tyree [BttP].  The Lurker Amis hangs around in the hull area (possibly Brown 95?) and is tracked to Brown 90 and Brown 91 [tLD].  These observations confirm that Brown Sector must also be a bona fide zone, in the wider part of the Carousel.  If we assume deck centres of 3-4m, the only place this can be is in the southern wider section.  Accordingly, we have placed the bulk of Brown Sector there, north of Grey Sector.  This is fortunate, since it allows us to situate the alien quarter in the built-up southern end of the Carousel.  All possible gravity environments may be offered, from near-zero g to greater than 1 standard gravity.

Some have speculated that because Brown Sector is a "dirty" zone, it must also contain the fusion reactor and fuel core.  This would place at least part of Brown Sector in a zero gravity zone, which is in general not borne out by the TV shows.  (There is some evidence from the schematic in [PoD] that mixed brown and yellow colouring extends as far as the reactor cooling fins).  There is a general aesthetic that wants Brown Sector to be less complete than Grey Sector and equate this with increasing distance from the more developed parts of the station (borne out by the schematic in [HP]).  However, we never see characters experience zero-gravity in Brown Sector.  All are seen to walk normally, rather than drift about. Although there must logically be a path down the core to the reactor, we only ever see service teams reach this directly from space [Con].

In our choice for Brown Sector, we have to discount the schematic in [SH], which labels the southern rotation collar as Brown Sector, because this would also be in zero-gravity.  Likewise, we have to discount the schematics in [PoD, HP], which place Brown Sector to the south of Grey Sector, because of the more compelling explanation in [SM] about the siting of Grey Sector as the most southern part of the Carousel, at the interface with the non-rotating part of the station, containing the rotation gear.

The Location of Yellow Sector

Although never mentioned by name in any dialogue in the TV shows, nor by JMS in his UseNet postings, the existence of a Yellow Sector, to denote the zero-gravity parts of the station, including the Spinal Collar, Fusion Reactor and Fuel Core, is a common assumption in a number of sources [PoD, SM, RPG].  At least one of the licensed novelisations (from the earlier, more "speculative" novel series) adopts Yellow Sector as the designation of the zero-gravity part of the station, specifically the zero-g docks.

The primary canonical evidence for the existence of a Yellow Sector comes from the episode [PoD].  The BabCom schematic read by the Minbari warrior Kalain in [PoD] sketches a wireframe outline of the station in yellow, and fills in the various sectors in different colours.  Looking closely at the Spine shows that this is also filled in with the yellow colour.  On similar inspection of the south part of the station containing the reactor, it is not quite clear whether the yellow outline is entirely filled with the same colour, or whether some of the in-filling is brown.  The secondary sources [SM, RPG] all have the zero-g spine and at least some of the reactor area as Yellow Sector.  The BabCom schematic read by a Soul Hunter [SH] colours all of the reactor area in yellow, with some penetration by brown and red zones.

In determining the proper extent of Yellow Sector, we have to resolve the contradictions between sources [SH, PoD, SM, RPG].  With regard to the south of the station, the main dissenting source is [RPG], which designates half of the fusion reactor area as being in Grey Sector.  This is so that the coolant pumps and cooling fins for the reactor can be found in Grey Sector.  Despite the fact that characters can hear the sound of the coolant pumps from Grey Sector [CoLaD], we should not make this an argument for extending Grey Sector into the zero-gravity fusion reactor area, since the observed part of Grey Sector in [CoLaD] is under simulated gravity and it would not make mechanical sense to transfer coolants between the non-rotating and rotating parts of the station.  We assume that Grey Sector is merely contiguous to the part of Yellow Sector that contains the coolant pumps.  In other respects, the source [RPG] is generally less reliable than other sources.

After this, the main aesthetic tension is whether to classify the whole fusion reactor area as part of Yellow Sector, because it is in zero-gravity, or as part of Brown Sector, because it is one of the "dirty zones" of Babylon 5.  The weight of evidence is in favour of Yellow Sector [SH, SM] and so we discount the brown intrusions of [PoD].  Brown Sector is best reserved for the recycling of organic waste; and this is a different matter from handling toxic radioactive materials.  We prefer to treat the whole of the fusion reactor area, from the cooling fins to the core fuel tanks, as being in Yellow Sector.

With regard to the spine of the station, sources [SM, RPG and PoD] are all in agreement that these constitute part of Yellow Sector.  Only [SH] provides a dissenting view.  Here, the spine is undesignated for most of its length, but with some sections coloured yellow and red.  This was taken as evidence that the [SH] schematic might not refer to a colour-coded map of the station's sectors, but could represent something else.  We go with the majority view that the whole length of the spine is part of Yellow Sector, containing the zero-g docks, cargo unloaders, raw materials storage tanks and transfer area to the south.