Heavy Engineering

The Heavy Engineering zone on Grey 12 is where major components of Babylon 5 are fabricated and repaired.  This requires detailed technical expertise.  If you are not a qualified engineer, then you may need to visit Grey 7 to consult the principles of interpretation and rules of measurement.  Visit Grey 1 and Grey 3 to find out how we resolved the station's coloured sectors and numbered levels.  Visit Grey 17 to find out about topological inconsistencies in the canon materials.

The Main Length of Babylon 5

The season 1 and season 2 narratives cite Babylon 5 as being "five miles long" [MotFL]. This is approximately 8km long.  More precisely, using a standard conversion:

However, this estimate is superceded by a caption from ISN, that ran with Cynthia Torqueman's news broadcast in 2259 [aNfaW], which cites the length of the station as 8.0645km exactly, to the half-meter.  So, if we accept this as canon, does this refer to the entire length of the station, or just to the main part of the station, excluding the projecting horns of the zero-g docking stabilizers?

There are two other useful sources: Sierra Studio's Official Guide to Babylon 5, aka the Babylon 5 Reference CD [CD]; and Jim Mortimore's The Babylon 5 Security Manual, published by Boxtree in the UK [SM].  Both of these have station plans with kilometre marks superimposed.  The 8km limit occurs approximately at the front of the Command Sphere, both in [SM] and in [CD], so we have to infer that the ISN data excludes the projecting horns of the docking stabilizers, which would add something over 450m to this.  So, the canonical 8.0645km length refers to the main part of the station, running from the fuel core slush tanks to the face of the Command Sphere, excluding the horns of the docking stabilizers.

Using the kilometre markers from Tim Earls' plans [SM]

Counting pixels in a screenshot from the Sierra B5 reference CD-ROM [CD]

The Full Length of Babylon 5

To estimate the full length of the station, including the horns of the zero-g dock, we have to refer to the kilometre markers in the Babylon 5 Security Manual [SM], which reproduces Tim Earls' original plans for the station (the digitial image above was supplied by Ben Gilboa).  From this we may estimate a mm-to-km scale.  Alternatively, we may make measurements from a similar-looking screenshot from Sierra's B5 Reference [CD], and either count pixels, or again use a ruler to establish a scale.

In the [SM] figure, p12-13, the scale used is 297mm = 8km, so 37.125mm = 1km.  According to this scale, the main station measures 296mm = 7.973km from the fuel core tanks to the tips of the instrument guidance array projecting around the main docking bay entrance. This is too short!  The horns of the docking bay project another 18mm = 0.485km, making a total station length of 314mm = 8.458km.  This is an underestimate, which we should scale up using the known length of the main station.

In the [CD] figure, the apparent scale used (on my 17 inch monitor) is 223mm = 8km, so 27.875mm = 1km.  According to this scale, the main station measures 223mm = 8km exactly to the tips of the instrument guidance array.  The horns of the zero-g docking bay project for another 13mm = 0.466km.  This gives a total length of 236mm = 8.466km, which is better, but still slightly short.

By scaling the length of the main part of the station in each figure to the published canonical length k = 8064.5m, two estimates are obtained for the total length:

Averaging these fairly close figures (20m apart) gives a total length of t = 8545km, the docking horns adding approximately 480m to the length of the station.

The Width of Babylon 5's Carousel

The diameter of the Carousel can be measured at three points:

To estimate these distances, we refer again to [SM] and [CD] and use the same technique as we did for estimating the full length of Babylon 5, in order to scale these figure estimates to the known length of the main station.  Note that when measuring the narrowest part of the Carousel, we are careful not to include the thickness of the longitudinal supporting strut, this can be cross-checked by measuring the plan view as well as the elevation view in both figures.

According to [SM], with its scale of 37.125mm = 1km, the measured and re-scaled diameters are:

According to [CD], with its scale of 27.875mm = 1km, the measured and re-scaled diameters are:

The [SM] and [CD] scaled measurements differ by 13m (widest), 13m (middle) and 3m (narrowest). Again, taking the average of these scaled measurements, we have: the Carousel measures w = 994m at its widest, m = 880m in the middle and n = 799m at its narrowest, to the nearest meter.

The Height of Babylon 5's Solar Arrays

The highest projecting parts of Babylon 5 are the solar arrays, situated next to the southerly (back) end of the Carousel.  The arrays are made up of two sets of six solar panels, projecting three up and three down in a direction orthogonal to the station's main axis.  To estimate their total height, we refer again to [SM] and [CD] and use the same technique as we did for estimating the full length of Babylon 5, in order to scale these figure estimates to the known length of the main station.

According to [SM], with its scale of 37.125mm = 1km, the measured and re-scaled distance between the upper and lower tips of the solar arrays are:

According to [CD], with its scale of 27.875mm = 1km, the measured and re-scaled distance between the upper and lower tips of the solar arrays are:

These are 48m apart, due to the greater differences in the figures and the boosting influence of the scaling factors.  Although these figures are rather disparate, we can still attempt to estimate an average height of the solar arrays, h = 2605m, more than two and a half kilometres!

The Internal Dimensions of Babylon5

A quantity of significant interest is the internal diameter of the main part of the station, since this relates to the rotational speed and the acceleration required to simulate 1 gravity.  The only direct evidence for internal measurements comes from [SM].  There are several ways to obtain estimates.  In the following w, m, n refer to our previous estimates of the external diameter of the Carousel at its widest, middle and narrowest points.

A longitudinal cutaway on [SM] p14-15 has the ratio of w:m:n:d of 44:39:36:32, where d is the internal diameter.  This would give d = 723m (using w), d = 722m (using m), d = 710m (using n).

A cross-sectional cutaway on [SM] p18 could either be of the narrowest or middle part of the Carousel.  It shows the Zen Garden (narrow) and hydroponics (middle), making you think it's a collapsed section.  But you can check by comparing this with the (wide) cross-section of Red Sector on [SM] p16.  Both have the same internal diameter, but no scale information.  If x is the external diameter measured on page 18, then the ratio of w:x:d is 95:86:71, where x must correspond to either n or m.  This would give: d = 743m (using w), d = 726m (using x=m), d = 660m (using x=n).  This last figure is way off, so we can assert that p18 describes the cross-section in the exact middle of the Carousel.  Averaging all the other estimates gives: d = 724.5m and if two further outliers are rejected, d =724m.  We shall take this figure, because it is the most robust.

From the formula 2*pi*r we can calculate the inner circumference of the Carousel as:  2*pi*r = pi*d = 3.14159 * 724 = 2275m.  Out of interest, that's a good two and a quarter kilometre walk round the interior of the station!

The inner length of the main garden part of the Carousel can be estimated directly from the kilometre marks on [CD], on the assumption that the wider-diameter sections close off the open part of the garden.  This would be consistent with the cutaway sections in [SM].  From [CD], the open distance is exactly 2km.

The Rotational Speed of Babylon 5

There are two pieces of direct evidence concerning the rotation of Babylon 5.  There are a number of exterior sequences in the TV shows which show the front end of the station rotating.  We can try to estimate one complete period of rotation by looking at timed quarter-rotations of the station and measuring when a regularly-spaced marker (such as a Cobra Bay arm) disappears into shadow under the Spine.  Unfortunately, there are not many long-enough film sequences and it is hard to estimate the times accurately.

Another piece of evidence comes from the season 2 closing episode [tFoN], in which Sheridan leaps from the booby-trapped core shuttle towards the rotating inner circumference of the Carousel, which Susan Ivanova says is rotating at "60 miles per hour".  To check this, we can reverse-engineer from the speed necessary to simulate 1g acceleration inside the Carousel.

From the later TV shows and [SM] p14-15, it's clear that a large portion of the main Carousel is built to a standard internal radius, so assume this is the 1g level.  It extends through Green and Red Sectors; the heaviest Blue Sector deck would then experience less than 1g.  The wider parts of the Carousel would experience more than 1g, which is consistent with providing environments with different strengths of gravity.  Starting with some known data:

One formula has g = v²/r, where v is the tangential velocity. So, v = sqrt(r*g) = 59.59m/s, or 60m/s to the nearest m/s.

This contradicts Ivanova in [tFoN] where she says "60 miles per hour".  If this were true, the Carousel would experience only about 1/5g and station personnel would be jumping around like moonwalkers!  We can show this from the same formula:

So, I'm afraid I have to insist that: "Ivanova is NOT always right, Ivanova is NOT God and I will NOT always listen to Ivanova" (after her outburst in [aVitW1]), sorry, Susan!  But it's instructive to notice that, if we convert her "60 miles per hour" into 60m/s, we are back in the right ball-park.  Perhaps she simply mis-read the units in the station manual, in her haste to help Sheridan!

From the tangential velocity at the internal circumference, we can estimate the period of rotation.  The internal circumference of the Carousel is 2275m.  This distance would be covered in one rotation.  According to Ivanova, the station only rotates at 26.82m/s, which works out at one rotation every 2275/26.82 = 84.82 seconds, approximately one minute and 15 seconds.  If our more accurate estimate of 59.59m/s is used, then the station completes one rotation every 2275/59.59 = 38.18s, approximately every 38s.

We can cross-check this figure using another formula for the acceleration due to rotation:  g = a²*r, where a is angular velocity in radians/s.  There are 2*pi radians in a single rotation, so:

These two calculations are in close agreement, showing that the formulae do calculate the same quantities.  For scientific accuracy, we must go with a rotational period of 38s and a tangential velocity of 60m/s.

The Higher-Gravity Areas of Babylon 5

If we assume that the interior surface of the Carousel is designed to give 1g Earth-standard gravity when rotating at 60m/s, then we can estimate what the higher gravity values are in those sections of the station that extend beyond the minimum diameter of the carousel.  Earlier, we determined that the external diameter of the widest parts of the Carousel was 994m (at the north and south ends, the built-up Red and Brown sectors), and the external diameter of the middle-width part of the Carousel was 880m.  

We need to obtain the maximum internal radius for these two parts.  If we may assume the triple-skinned hull of "downbelow" (Corwin speaks of hull levels A, B and C [aVitW2]) and deck centres spaced at about 4m, then we may subtract three decks to obtain:

Using the same calculation for gravity using the previously calculated angular velocity a = 0.1646radians/s, we may calculate:

So given that Earth-standard gravity 1g = 9.81m/s², then the high gravity areas correspond (in terms of Earth standard gravities) to:

These don't seem to be a lot higher than Earth-standard gravity.  So perhaps Babylon 5 does not have to cater to lifeforms that come from 2g super-Earth planets.  Alternatively, the Carousel may be more complicated than a simple cylinder, and one could imagine parts of the Diplomatic Quarter in Green Sector that rotated at a different speed.  But this would make it hard to transfer from one part of the station to another.

The Colour-Coded Sectors of Babylon 5

Babylon 5 is divided up into a number of colour-coded sectors, representing the different zones of the station.  From the many TV shows which mention them, we know that:

There are a number of sources citing the locations of these zones.  The most authoritative is the season 2 opening episode [PoD], where a warrior caste Minbari Kalain accesses a BabCom terminal which delivers a schematic of the station.  The second source of information is Jim Mortimore's Babylon 5 Security Manual [SM], published by Boxtree in the UK, which gives a breakdown of the zones covered by each Sector on p14-15.  The third source is Cochran's The Babylon Project [RPG], published by Chameleon Eclectic/WireFrame Productions in the US and Titan Books in the UK.  Of the three sources, [RPG] makes some fairly wild guesses about the locations and functions of zones which obviously do not tally with the TV shows.

It is possible to make a number of reliable estimates on the locations of some of the sectors, based on their known functions.  The locations and extents of other sectors can be surmised by fitting together the remaining pieces in the jigsaw.  The two main problems to resolve are the siting and extent of Green and Brown Sectors.  Most sources assume that sectors are contiguous major areas, rather than a collection of smaller, distributed zones that are simply labelled according to their function.  There is some disagreement over whether the entire station is partitioned exhaustively into sectors, or whether parts of the station are unclassified.

Here we cite the sources of reference used to help build up a consistent view of the dimensions of the Babylon 5 Station.