ACCELERATION & VELOCITY

Definition of acceleration is: the rate of change in velocity.

Speeds at which vessels in the Babylon 5 universe travel very greatly depending on the technology level of the given race.

The Minbari, who have thus been shown to date as having the most advanced technology of the younger races, has the fastest and most powerful ships, capable of obtaining velocities up to and in excess of 20% the speed of light.

Races like the Narn and Earth Alliance are far more limited, their particle-thrust engines allowing their large scale capital ships to accelerate at no greater than 40 m/s².

It should be noted that velocity is not as important as acceleration. A ship traveling at only 10 m/s² - or approximately one g-force - could, in theory, accelerate to speeds near that of light. This doesn't make said vessel fast however. In reality, it makes it very slow and the time required to come to a velocity anywhere close to light would take too long for anyone to survive and be almost impossible given the fuel requirements.

Given that we don't have any official information about the acceleration rate of the many vessels of Babylon 5, we will discuss herein the subject of acceleration and the question of just how fast the ships of Babylon 5 really are. Subject of this essay will include the Shadow Battle-Crab, Minbari War-Cruiser, Omega class Destroyer, the Whitestar and the newest ship of the Babylon 5 universe... Excalibur.

First of all, there is a difference between acceleration and velocity. In space combat, the only thing that matters is acceleration - how fast a ship can go, from "point A" to "point B" in a given measure of time. For example, in the season three episode "Shadow Dancing", a fleet of Shadow vessels approach a target planet in "Sector 83", where the Shadow's hit-and-run attacks had culled refugee ships trying to find shelter from the killing zone. Shadows' proceed at a constant velocity towards the planet, some three hours away. Between the Shadows and the planet is Ivanova's disabled Whitestar, some 20 minutes out from the Shadow fleet, at a distance of just under 5,000 kilometers.

These figures allow us to determine how fast the Shadow fleet was moving at any given second using the formula V=d/t, where V=velocity, d=distance and t=time. This makes our figures come out to V=5*10⁶m / 1200 sec. As such the Shadow fleet was maintaining a uniform velocity of 4.2 kms, or 15,120 kph. Some have tried to use this scene to claim that the Shadow's only had a rate of "acceleration" of 4.2 kms, but these people are in error. We did NOT see the Shadow fleet accelerate towards the safe haven in "Sector 83", thus we can not determine the acceleration of the Shadow vessels from this scene.

A far more accurate indication of acceleration for both the Shadow vessels and the Whitestar comes from the season three episode "Messages from Earth", where Sheridan and the Whitestar prototype are chased by a Shadow vessel from the moon of Ganymede to Jupiter, over the course of no more than 38 seconds. The average distance between Jupiter and Ganymedeis 1.07 million km, and as such, if we assume that the Whitestar and pursuing Shadow vessel accelerated only half that distance before slowing down in anticipation of entering Jupiter's atmosphere (if they slowed down at all), then the low-end rate of acceleration would be as follows:

A = 2S / (2t - 1)

Where the distance of acceleration is one half the total distance between Ganymede and Jupiter, and the time is 38 seconds from Sheridan giving the order to head for Jupiter and Lennier's comment that they had entered the atmosphere, our figure comes out to be:

A = 2*535000000 / (2*38 -1)
A = 1070000000 / (75)
A = 14266666.67

As such, the low-end rate of acceleration for the Whitestar and the Shadow vessel as depicted in this episode, comes to 1.4*10⁷ m/s² or 1.45 million g-forces. This is, of course, the minimal rate of acceleration, assuming that both ships slowed down at the half-way point. In reality, given that Sheridan was being chased by an attacking vessel with superior fire power, it would be highly illogical to slow down half way to your destination, when you are in fact running away and still under attack.

Given these facts, the maximum accleration for the Whitestar and persuing Shadow vessel would have been 2.8*10⁷ m/s² or 2.9 million g-forces, if the Whitestar continued to accelerate all the way up to the point when she entered the atmosphere. This would have meant the Whitetar would have absorbed a considerable ammount of energy upon entering the atmosphere due to friction, no matter what kind of trojectory she used to safely enter Jupiter. Still, this scene would appear to give the advanced ships of Babylon 5 a high-end acceleration of 28,533 km/s².

Even at this, we do not know exact distances and we don't know the time frame as the Shadow/Whitestar may have only accelerated for as little as 1/4 the given distance or could have been accelerating the whole way! Logic suggests that the Whitestar, fleeing from a rampaging Shadow vessel, would be accelerating and continue accelerating all the way to Jupiter. Again, we just don't know 100% for sure, thus these figures are only as a tentitive explanation as to the possible rate of acceleration of both these vessels, baring additional information. Still, at MINIMAL it would appear that both the Shadow Battle Crab and Minbari Whitestar have a rate of acceleration no less than 7.13 million m/s².

Ships like the Sharlin were said to have a cruising speed of 0.2c, but this is again a statement as to the ship's velocity, not acceleration. It would be nice to assume that this represented acceleration, but it is very unlikely that even a race as advanced as the Minbari can accelerate in real-space so quickly. Granted the maximum acceleration of the Whitestar and Shadow vessels may come to approximately 0.1c, but both of these vessels are faster than a Sharlin. As such, the statement is taken as what it is - the vessel's cruising velocity.

As we never saw the Minbari War-Cruiser ever forced to go from a dead-stop to full speed, at any time during Babylon 5's six year run, we can not really gage this vessel's rate of acceleration. The only ship that comes close to giving us a glimpse into the War-Cruiser's possible rate of acceleration would be the Excalibur, as they rely on manyof the same technologies... a subject we will tackle later in this document.

Ships like those of the Narn and Earth Alliance rely on conventional physics, as they are not in posession of artificial gravity technology... at least not until after joining the Interstellar Alliance. All vessels before this relied on z-axis or simulated gravity i.e. the use of acceleration or ratating sections. Due to this fact, most ships without rotating sections were limited to a maximum rate of acceleration of no more than 40 m/s². Ships with rotating sections, like the Earth Alliance's Omega class Destroyer, were limited to an acceleration of no more than 10 m/s² as acceleration beyond that speeds would require the ship to increse the speed at wich the revolving section moved, to compensate for the creation of z-axis gravity and thus placing a great deal of strain on the ship's frame as well as the crew.

Thus far, the only ship amongst the younger races that gives us a good idea of just how fast "fast" is the ISA Excalibur. Even then, there is no way to judge the acceleration rate 100% accurately, but we can do so more accurately than what was seen in the afformentioned examples. Again, speed really doesn't matter, only acceleration. Best scene offered in the series "Crusade" with regards to acceleration, comes from the episode "Each Night I Dream of Home", where Exclaibur travels a stated distance in a measurable period of time.

Unfortunately, we can not judge acceleration accurately unless you have a vessel going from a dead stop to full speed, and moving a predefined distance in a certain amount of time - something we didn't see in this episode. Still, we have enough information to make some fairly reasonable educated guesses.

First off, we must know what we are looking for, in this case the ship's velocities. Velocity is determined by a simple formula of V=D/T, where V = velocity, D = distance and T = time.

The distance Excalibur had to travel in order to intercept Lochly's Starfury was approximately 5,000 kilometers. It took 86 seconds for Excalibur to reach Lochly. As such we know the distances and the time in which the stated distance was covered. V=D/T, which would come out to be "Velocity = 58km/s." (NOTE: This is assuming of course that the scene of Lochly watching the approaching Excalibur happened AFTER the previous scene, and not during, and doesn't take into account the time it took the crew to impliment Gideon's order to slow 1/3.)

What does this mean? Nothing. Why? Because we can not determine Excalibur's acceleration from this scene, from the limited information offered. Why? Because the afformentioned figures' state uniform velocity, not accleleration and Excalibur was NOT accelerating in this scene.

There are several things we don't know. We do NOT know how fast Excalibur was going when she jumped, or how much they slowed down before jumping to normal space, if at all (it wouldn't appear they slowed down at all given Gideon's comments). Given that Gideon had Matherson cut the ship's speed a few seconds after existing Hyperspace by 1/3, Excalibur was likely moving no faster than 174 km/s when she jumped out. Plus Excalibur may have been slowing down the entire time, while approaching Lochly's Starfury, or may have decelerated to 1/3 in as little as a tenth of that length/time.

Again, and I can't stress this more fervantly, acceleration can NOT be determined from this scene given the ammount of information available, making the scene useless in determining the maximum speed/acceleration of Excalibur. Only way you could figure out acceleration using this scene, is if we make a some educated guesses... which I am about to do.

If we GUESS that Excalibur needed the whole 5000 km to drop to 58km/s (unlikely), then we can reverse the figures and come up with a probable rate of acceleration, even though this guess will not be completely accurate as we do NOT know how long it took Excalibur to slow down. We can only GUESS how long it took to slow down.

Difference between initial and final velocity is 116km. If Excalibur can accelerate from 0 to 116km/s within 5000 kilometers in 86 seconds, than we can determine the ship's acceleration using the same formula for finding the distance traveled in any given second.

S=1/2a(2t-1) S=distance a=acceleration t=time.

5000=1/2a(172-1)

To find "a", we simply divide 5000 by 171, then multiply by 2.

So, if we guessed correctly and it DID take the entire 5000 km to decelerate to 1/3 the ship's initial velocity, and we reverse those figures (assuming that acceleration and deceleration on the Excalibur is equal), the Excalibur's LOW-END rate of acceleration is no less than 58.5km/s². Given that it took a second or two for Gideon's orders to be executed, we can round this figure up, placing Excalibur's low-end acceleration at 60 km/s².

Again, this is a LOW-END estimate, given that we don't know the distance required by Excalibur to cut her innitial velocity by 1/3, so the ship's maximum velocity may well be signifcantly higher than the stated figure of 60km/s².

CONCLUSSION:

Acceleration rate of low-tech races such as the Earth Alliance and Narn Regime (before 2263) are limited to between 10 and 40 m/s².

Acceleration rate of Minbari capital ships and the Excalibur is no less than 60 km/s²

Acceleration rate for Vorlon, Shadow and Whitestar class vessels is no less than 7,000 km/s²