Ramming and Subspace Physics

Kinetic energy's use as a weapon on this planet is older than mankind itself, though we have perhaps brought it to its fullest flower.   From spears and arrows to minie balls, DU rounds, and the Deep Impact probe, mankind has demonstrated a pretty firm grasp on the idea that the energy of a moving object can do work on a target that the target might not entirely enjoy.

Our assortment of projectiles exist for various launching apparatii, target sizes, and purposes, but are all based on the simple principle that the heavier and/or faster a moving object is, the more effect it can have on its target.

I.  The 5,196.85-Caliber Bullet

As example, let's take something a bit larger than one's average bullet . . . say, USS Voyager.   

(bang!)

At 340-odd meters long and 700,000 metric tonnes, the ship could ruin a person's entire day even with a comparatively-gentle nudge.   For instance, a small car might weigh in at 750 kilograms, and if it's travelling at 100 kilometers per hour (about 60 miles per hour) it will have a kinetic energy of almost 300 kilojoules.  Voyager achieves this same KE at less than 0.03 meters per second.  At 100 km/h, the 700,000 tonnes of Voyager . . . quite a bit heavier than the car . . . result in a KE of just over 27 trillion joules.   That's 27 terajoules, or almost 6.5 kilotons.

Now, consider Voyager at not-even-relativistic speeds.   For instance, Voyager at just 10 kilometers per second . . . Mach 30 at sea level, or 0.00003334c . . . is going to have a kinetic energy of 35,000 terajoules, or almost 8.4 megatons.  At one-tenth lightspeed, we're looking at 75,000 gigatons.  At one-half lightspeed, we're looking at somewhere in the neighborhood of 2,000,000 gigatons . . . about 8E24 joules, or eight quadrillion terajoules.  

At faster speeds, relativistic effects come into play in earnest.  At .9c, for instance, we're looking at over 8E25J . . . almost 20,000,000 gigatons, instead of the 'mere' 6,000,000 gigatons non-relativistic calculations might indicate.

Obviously, then, a ship moving sufficiently fast can rearrange a hellacious amount of real estate.  At .5c, a starship of Voyager size augering straight into an Earth-like planet could blast a hole over 100 miles wide, laying waste to civilization within a 2500 mile radius.

II.  Cochrane > Einstein

With faster speeds and higher masses resulting in more effective projectiles, someone wanting to make the perfect projectile would be stuck.  After all, there's that pesky lightspeed barrier in the real world, meaning that even if you could magically accelerate any-size mass to 99.999999% of lightspeed, you'd never be able to really make them go any faster.  The most you could hope to do is just keep making bigger and bigger projectiles.

In Star Trek, however, that real-world barrier doesn't exist . . . or, more accurately, warp-capable species have found a way around it.  With warp drive, they're able to take very massive starships and fly about at well beyond lightspeed.

And so with faster-than-light (FTL) propulsion, the question thus must be asked . . . where are the warp projectiles?   Or, if for whatever reason you'd need an actual ship instead of a simple missile, then where are the kamikaze attacks?

III.  The Divine Wind at FTL Speed

The idea of the utility of warp ramming has a certain common-sense appeal.   Indeed, even Trek tech guru Rick Sternbach leant the general idea his support on TrekBBS.   After all, it seems almost a given that a ship doing 20,000 times the speed of light ought to make a hellaciously good cannonball.  Indeed, were the non-relativistic equation actually useful for FTL velocities, it would suggest that a Voyager-mass projectile at 20,000c would have a KE in the area of 1.26E34J . . . over 3 million exatons.  That would be more than sufficient to blast a planet into rubble.  Even at a mere 1000c, you're looking at 3E31J, which is almost as bad.  At 1000c, a single neutron (weighing in at 1.674986698E-27kg) would have a kinetic energy of 0.000075J . . . meaning only about 14,000 neutrons and protons (protons being of similar mass) would be required to create one joule of KE.  A single E. coli bacterium has a mass 400 billion times that of a single neutron, so it's easy to see how even small masses could start to hurt.

If our reasoning thus far were remotely accurate the consequences would be profound.  Let's ponder it from the example of the Dominion War, for instance.   Consider that Weyoun felt any resistance to Dominion rule would be centered on Earth ("Sacrifice of Angels"[DSN6]).   Consider also that even when the war was turning against the Dominion, certain vessels of the DCB axis were able to get to Earth and attempt to attack San Francisco, causing minor damage to the city ("The Changing Face of Evil"[DSN7]).  We're also told in Nemesis that the destruction of Earth could cripple the Federation.  Even beyond the Federation capital world, there are numerous large starbases, outposts, and other fixed fortifications, from Deep Space Nine to Starbase 375 to fairly enormous facilities such as Starbase 73.

If warp ramming were so easily performed, then Patton would be right:  "Fixed fortifications are monuments to the stupidity of man."

Given that we've seen fixed fortifications, and of course given the inevitability of planet-based civilizations, then a civilization with spacefaring enemies would have to have some sort of planetary/system defense against FTL vessels or missiles.  They'd have to know the enemy was coming and have sufficient resources at hand to disable or destroy any and all incoming FTL objects, or at least to shield the planet against such catastrophic impacts.

However, no active defense system capable of thwarting a warp attacker has been observed at planets, or even stationary objects like space stations.   The one exception to this was the FTL verteron beam in use from Mars during the mid-22nd Century ("Demons" & "Terra Prime"[ENT4]), but there's still no indication of a targeting system allowing for precision strikes on warping vessels.  Indeed, a hundred years later the Enterprise had extreme difficulty scoring hits on a ship performing warp strafing maneuvers in "Journey to Babel"[TOS2], and there is questionable tracking of shuttle-sized vessels within the Terran system a hundred years after that (re: Titan's Turn, "Chain of Command, Pt. II"[TNG6], "The First Duty"[TNG5], et al.).  And, while planetary shields have been seen to exist in Star Trek, we've never had any indication that they're powerful enough to withstand a planet-killing hit.

So, either (a) this is a devastating method of attack that no one has thought of, or (b) it is not, in fact, a devastating method of attack at all.   In other words, either everyone's stupid or else our reasoning from above was somehow incorrect and warp ramming doesn't work.

So, we must now (a) confirm that it isn't a viable tactic, and (b) ponder the notion of why it isn't a useful tactic, despite the common-sense appeal of the idea that it is.

IV.  Ramming Speed is Not FTL?

A. FTL Projectiles

The most obvious evidence against warp-ramming involves those warp-driven missiles that were, either by design or observed implementation, used to strike sublight targets:

1. Photon torpedoes have been used at warp against sublight targets on multiple occasions.

2. "Dreadnaught"[VOY2] was an experimental self-guided warp-driven "tactical missile" of Cardassian manufacture.  Equipped with advanced defensive weaponry, a sophisticated computer system, and a payload of 2000kg of matter and antimatter, the unit was said to be capable of destroying a small moon.   When deployed, it would warp to its target, drop to sublight within the system, and then cruise in toward impact.

3. "Warhead"[VOY5] featured the torpedo-sized Druoda "Series 5".  The unit was similar in principle to the Cardassian tactical missile, though with a sentient AI and no observed defensive weapons.  It carried some sort of explosive charge detonated during its impulse  approach, though the nature of the charge is never clearly revealed.   (The Series 5 was shown to be capable of producing a 400km-diameter gaping wound in a planet's surface via a "highly focused explosion", despite being small and light enough for two people to carry without antigravs.  There was mention of an antimatter explosion when the unit self-destructed, but the unit's power matrix was reportedly capable of powering numerous ships and thus was presumably not based on antimatter.)

4.  In "Blaze of Glory"[DSN5], the Maquis concoct a ruse designed to lure Sisko to the last surviving Maquis stronghold, suggested in the ruse to be a launch site for a retaliatory strike against Cardassia and the Dominion.  The site within the Badlands had supposedly launched missiles on a two-week trip to Cardassia, missiles making use of some of the 30 Class-IV cloaking devices given to the Maquis by the Klingon Empire for use on their ships.  Upon learning of these cloaked warp missiles, Sisko's first thought was in regards to the payload they could carry, including tricobalt explosives (see "Caretaker"[VOY1]), antimatter warheads, and a non-explosive payload of biogenic weapons.   Happily these Maquis missiles did not exist, but had they existed they clearly would've been expected to carry a payload of some sort.

The above examples share the same common element . . . not only is there an "FTL rocket", but also something to make it go boom.  While one could argue that this is merely insurance in the case of low-relative-velocity intercepts, it is never presented as such. The missile examples are clearly intended for use against fixed targets, and even drop out of warp to do the deed.  Further, when Tuvok pondered the Cardassian missile's yield, he did not do so in reference to its impact speed, but in reference to the amount of matter and antimatter it contained.

If an FTL projectile produced devastating effects upon impact due to raw KE, there would be no purpose in having explosives aboard.   Indeed, given the use of the missiles against fixed targets, there would be no point in having them drop out of warp at all.

B.  Warp Storms

"The Lights of Zetar"[TOS3] featured a warp ram, of sorts.  The Enterprise detected a "storm" in space moving at warp speed.  Kirk, however, comments that no natural phenomenon can move at faster than lightspeed, and Spock concurs, noting that thus it must not be a phenomenon of nature.   (Presumably they are referring to macroscopic phenomena, since tachyons travel at FTL velocity and are a known quantity in the Trek canon.  And, the energy phenomena from "Lonely Among Us"[TNG1] is (a) composed of "nothing solid" and (b) 100 years later.)  

Kirk and Spock are correct, in a sense . . . the storm is a collection of "life-units" from the dead race known as the Zetarians.   While the nature of their appearance and ability to travel at warp velocity is never delved into within the episode, the original belief that the Zetarians are a "storm" producing "high-intensity readings" would seem to imply that they are composed of particles of some form of matter . . . as would the lifeforms' susceptibility to high atmospheric pressure.

Despite their pressure problem, however, the Zetarian storm does strike the Enterprise at greater than warp 2.6, and later strikes the Memory Alpha planetoid at "incredible" warp speed.   The Enterprise, hit with her shields up, is almost completely unaffected.  The unshielded planetoid Memory Alpha does take some damage inasmuch as the generators stop functioning and the memory core is burned out, but there is no apparent physical damage to the facility.

A more solid example comes in "The Catwalk"[ENT2], which features a phenomenon of uncertain origin.  Called a class five neutronic wavefront, the disturbance travels at "high warp", requiring a warp seven velocity to outrun it.  Enterprise, unable to make more than warp five, is forced to batten down the hatches and ride out the storm.   The wavefront produces various eddies and currents that are slower than light and visible to the naked eye, like almost-but-not-quite standing waves in water.  The ship is tossed about by gravimetric spatial distortions, but incurs no significant damage from the particle impacts.  (The only reason they go into the well-shielded nacelle catwalk is to avoid the deadly "radiolytic isotopes" in the storm.)

(There is no mention of neutron radiation in this particular neutronic wavefront, nor is there any explanation for why it is travelling faster-than-light.  Evidently in the intervening century it was determined to be an artificial phenomenon, possibly related in some way to the only known radiolytic compound, kemacite, used in the Xindi weapons.  Alternately, it could be related to something similar to the multikinetic neutronic mine, a Borg device that was intended to be modified to distribute nanoprobes across five light-years of space.

In any case, the reason the artificialness of the phenomenon can be inferred is because of (a) Kirk and Spock's reaction, and (b) in "Fair Haven"[VOY6] we see a class nine neutronic wavefront.  Travelling at a 'mere' 200,000km/s (about two-thirds lightspeed), the wavefront is determined to have originated with the collision of two neutron stars.  Such a collision obviously would not cause neutrons to jump to warp.)

C.  Ramming Speed

In First Contact, the Defiant is battered by the Borg.  With the stated loss of main power and weapons, not to mention visible damage to her warp engines, it is unlikely that the vessel had warp drive available.  Nonetheless, Worf gives the order:  "prepare for ramming speed!"   This implies that he was referring to an impulse velocity.

Still, though, there has been an instance of a similar order being given that has opposing implications.  In "Best of Both Worlds, Pt. II" the Enterprise-D finds herself gripped by a Borg tractor beam as the ship is again carved up.  With Data's attempt to access the Collective an uncertainty, Riker orders a collision course laid in and warp power at his command.

Though our first reaction might be to conclude that Riker intended to ram the Borg cube at warp speed and thereby produce a devastating effect, that actually doesn't fit the situation.   Oh, indeed, I'm sure Riker figured that they'd hit the Borg ship and hoped that they'd clobber it, but it doesn't follow given the rest of the examples that the warp ram would be the reaming a common-sense view would suggest.  After all, the context of the event features the hopeless battle of Wolf 359, which Admiral Hansen had described as "our stand". In that battle, or in other examples from the canon, where was the ramming? How about a good warp KE missile? Why the old coffin-filled-with-explosives trick?

In the BoBW scene, the Enterprise-D is locked in a Borg tractor beam, and shields have failed.  The Borg are cutting into the hull. Hope is lost.   I submit that going to maximum warp was not intended to produce a devastating kinetic impact, but instead to simply work loose from the tractor beam and hit the Borg with all the Enterprise had left . . . herself.

After all, during the first encounter with the Borg ("Q Who?"[TNG2]), the Enterprise-D had also been locked in a Borg tractor beam.  Even in spite of the ship's shields, the Borg beam managed to hold the Enterprise in place and prevent her from getting away at Picard's ordered "warp eight, any heading".  Even when Riker ordered increased power during that event, the ship didn't budge.

It therefore follows that Riker would not have assumed that they could work loose from the Borg tractor beam via impulse.   And, since the Enterprise-D weapons were having no effect on the cube during the final moments of BoBW2, it therefore follows that Riker was indeed simply trying to get the ship loose . . . slamming into the Borg in a desperate last-ditch move would've simply been the icing on the cake.

V.  Subspace Physics and Impulse Ramming

With warp ramming never having been used, and with the counterevidence of explosive payloads for FTL projectiles and so on, the obvious question would be why it doesn't work.  After all, given that warp drive is intended to cheat relativity in the first place, one could almost allow the idea that the normal KE equation ought to work out just fine, too.

The answers, I believe, lay in subspace fields. We know from "Emissary"[DSN1] that these have an apparent mass-reducing effect, and of course they are part of what makes faster-than-light warp travel possible.  I would bet that subspace mechanics precludes the use of warp-driven objects as KE weapons.

This may also have ramifications for impulse ramming, given the implication in several episodes that subspace fields are required for sublight impulse flight as well.   Consider:   you're travelling in a spaceship doing 100km/h in the middle of nowhere.   You activate your mass-lightening field and . . . what?   Well, one of the fundamental ideas of physics is that of the conservation of momentum, and an object's momentum is defined as an object's mass times its velocity.  Unless subspace physics somehow cheats or bypasses conservation of momentum (say, by having momentum conserved (or not) in the subspace domain), then we would expect that activation of a mass-lightening field would shoot you off like a rocket.

In other words, if your mass were 2 mass-units (m_u) and your velocity were 2 velocity-units (v_u), then your momentum would be 4m_uv_u.   If your mass-lightening device were capable of cutting your apparent mass to just one-quarter of what it was, then by activating it you would reduce your momentum to 1m_uv_u.  Of course, conservation of momentum says this cannot be.  Something's got to pick up the slack, and  . . . since we only have two variables to work with . . . velocity's stuck with the job.   So, as your mass drops to .5m_u, your velocity will have to increase by a factor of four to 8v_u!   And all you have to do to slow back down is flip the switch back to 'off'.

The problem for impulse ramming is obvious.   Earlier we used various speeds for Voyager and calculated her kinetic energy based on her normal mass.  But, if she only got up to high speed by reducing her mass, then the associated kinetic energy calculations are bogus.   For example, let's assume that Voyager could reach ten kilometers per second by herself, without mass-lightening.   But, let's say we find an example of her accelerating to half the speed of light.   By conservation of momentum, her mass at that velocity would only be 46,700 kilograms . . . 46.7 metric tonnes, or 1/15000th what it originally was!

 That said, higher-velocity ramming would probably still be more advantageous.  Recall that changes to momentum involve a linear relationship between mass and velocity, whereas kinetic energy involves the square of the velocity.   In other words, the more speed you get the more it counts for the purposes of KE.   As proof, we can simply calculate the difference between full-mass Voyager at 10km/s versus 1/15000th-mass Voyager at half the speed of light:

 Even if Voyager could only do 100 kilometers per hour on her own (which, as previously calculated, would result in a KE of 27 terajoules, or almost 6.5 kilotons), turning on the artificial mass-reduction field to achieve half the speed of light would still make for a better ramming.   Under such conditions, the ship's mass would be a mere 130 kilograms, or just 1/5,400,000th of normal.  However, her KE would be 1,457,441 terajoules, or about 350 megatons . . . quite a bit better than the 6.5 kilotons that would've been involved without the mass-lightening field.

Unfortunately, there are any number of unknowns to consider if we wanted to apply this knowledge.  Most importantly, we don't know how much mass-lightening is actually occurring.   Just in the calcs above, Voyager flying at half the speed of light might have a KE of 350 megatons, 250,000 megatons, or . . . if there were no mass-lightening in play . . . 2,000,000 gigatons. It makes a significant difference, especially if you're Voyager's target!

We also don't know what would happen at impact.  For example, if you have a mass-reducing field around your ship and you slam into the ground, how do the particles of your rapidly-disassembling vessel behave in the sudden absence of the field?   (For that matter, is there a sudden absence of the field?   We know from "Encounter at Farpoint"[TNG1], "Brothers"[TNG4], "Treachery, Faith, and the Great River"[DSN7], "Year of Hell, Pt. I"[VOY4], "Future Tense"[ENT2], and "Divergence"[ENT4] that debris and other non-warp-capable items cast off at warp don't immediately drop out of warp . . . is the same true of the subspace fields of impulse?)   Will the pieces that are not yet jamming into the ground simply shatter due to the peculiar acceleration effects a mass-lightening field would cause?  (For that matter, is there acceleration related to the mass-lightening field activation/deactivation?)   And how does this affect the way the ship accelerates due to drive thrust, anyway?

Et cetera.

And, of course, this begs the question . . . if you can artificially reduce mass via subspace fields, can you also artificially increase it?   Per "Fair Haven"[VOY6], the answer is probably yes.   This would be intensely useful for ramming other ships, since if you could increase your apparent mass by a factor of thousands you could probably cut through the enemy ship like butter, provided you had some speed behind you.   However, in "Fair Haven" the act of generating an inverse warp field is referred to as 'dropping anchor' and requires unspecified conversion of the warp core, implying that at least for the Federation such a thing would not be useful in a tactical situation. 

VI.  Conclusions

 In short, warp ramming does not seem to be a viable tactic in Trek, presumably due to subspace mechanics.   And while impulse ramming may be a viable tactic, those subspace mechanics mean it's also a headache.

Special thanks to reader "Trev", who reminded me of the issue of debris at warp (as seen in "Treachery..." et al.) and to others who have mailed me on this topic