If the Romulans decided to send a few hundred cloaked warbirds to attack Earth, can they be detected upon crossing the neutral zone? Does Starfleet have any special sensor stations to detect/track a cloaked ship?

Secondly what are the defences around Earth and the solar system?

  • Millions of Star Trek freaks would crap themselves with delight.
    – Wad Cheber
    Jun 25, 2015 at 4:14
  • “what are the defences around Earth and the solar system?” They have some incredibly powerful tiny triangle-looking ships around Jupiter which were narrowly defeated by the Borg cube in Best of Both Worlds, part 2. Jun 25, 2015 at 9:01

4 Answers 4


If you're talking about the 24th century, cloaking technology is quite advanced at this point, but there are still some limited defenses.

Romulan cloaking technology

  • Not technically a part of the cloaking device, but Romulan warbirds use a quantum singularity to generate power instead of a matter-antimatter reaction that Federation and other warp drives use. Therefore, Romulan warbirds don't give off neutrino emissions as other cloaked ships do.
  • Additionally, Romulan ships are equipped with nullifier cores, which balance the radiative emissions of the cloaked ship.

Weaknesses of Romulan cloaking technology

  • While traveling at warp, cloaked ships radiate a slight subspace variance. The faster the ship travels, the more detectable this phenomenon becomes. Thus ships using Romulan cloaks generally limit their speed to warp 6.
  • Additionally, when traveling at high warp, the competing power demands of the cloaking device and the warp nacelles causes incomplete cloaking as well as potentially permanent damage to the warp drive.
  • Furthermore, while Romulan warbirds don't emit neutrinos, they do apparently register as high concentrations of tetryon particles. The closer the ship is, or the more ships are in a cloaked fleet, the more detectable these tetryon particles become.

Anti-cloaking techniques

  • During DS9: "Visionary", Jadzia Dax scanned the nearby space around the station out to a radius of 2 km. She didn't find anything at first, but then she began to focus on the lower subspace bandwidths and noticed traces of low level tetryon emissions. The emissions appeared to be orbiting the station in an elliptical path, and since there were no neutron stars nearby, the DS9 crew deduced that it must be coming from the quantum singularity of a cloaked Romulan warbird.

    Later on, this same technique was used by DS9 to detect a large cloaked joint Romulan-Cardassian fleet entering the wormhole to attack the Dominion.

  • The Romulan cloaking device also generates chroniton particles, which in theory could also be used for tracking and detection.
  • A gravitic sensor net is deployed near the Romulan neutral zone, but next to nothing is known about them aside from their not being 100% effective. TNG 6x14 ("Face of the Enemy") also mentions the border being littered with subspace listening posts as a potential threat to a cloaked Romulan ship.
  • Other active-scanning techniques have been used effectively against Romulan cloaks, such as the Federation's tachyon detection grid. However, this detection method requires that the cloaked ship travel through (thus "tripping") the tachyon field generated by an active tachyon beam being transmitted between two ships or sensing stations. The single-ship implementation of this is the tachyon scan, which has a much more limited range.

    Another known active-scanning technique uses antiproton beams. Romulan (and perhaps other) cloaking devices typically leave behind a trail of risidual antiprotons, which can be picked up using an antiproton beam. This is how the Jem'Hadar detect cloaked ships (including the Defiant)

    However, advanced ships like the Scimitar emit neither tachyons nor antiprotons and are thus impervious to all tachyon- or antiproton-based detection techniques. Luckily, the Scimitar appears to be a one-of-a-kind prototype, though the Remans surely retained this technology and could possibly deploy it once again at some point (then again, the Klingons never did manage to mass produce Chang's unique cloaking device once the prototype was destroyed).

What would happen

The Star Trek: Star Charts show that the Federation-Romulan neutral zone is the most heavily defended Federation border in the 24th century. There are 44 Federation outposts/space stations (Romeo Outposts, Sierra Outposts, Quebec Outposts, Tango Outposts and Earth Outposts) lining the neutral zone, in addition to 6 star bases. To reach Earth, the Romulan fleet would need to pass through not just the gravitic sensor net, but it would have to get past tachyon scans by Federation patrols as well as Federation outposts, starbases, and the protected space of Federation member planets/systems:

  • Argelius II
  • Caleb IV
  • Benzar
  • Andoria
  • Ophichiucus III
  • Sirius IX
  • Proxima Centauri
  • Teneebia
  • Regel
  • etc.

Any massed formation of dozens or more warbirds would easily be detected on long-range sensors by Federation border outposts even before they crossed the neutral zone and would be engaged long before they reached Earth. The Romulans would not just be waging war against Earth but against the Federation and all of its allies, most notably the Klingons. Between the Federation and the Klingons, the Romulans are effectively flanked from all sides, with only a 50 light-year gap that prevents them from being completely surrounded.

Strange readings along the neutral zone

Most likely what would happen is that Federation outposts would detect the large Romulan fleet massing on the other side of the neutral zone by their enormous tetryon signature. At this point, the element of surprise would be lost and the cloaks would only be good for avoiding the targeting scanners of intercepting vessels.

Starfleet would send its response fleet to intercept the Romulans and also deploy a tachyon detection grid if the Romulan fleet disperses into smaller 2-3 ship elements to try to evade detection. All Federation science stations and military bases would also be put on high alert, making tachyon sweeps for cloaked ships.

A war on two fronts

A communique would be sent to Qo'noS, as the Klingon High Council would surely want to launch its own offensive against their, now very vulnerable, sworn enemies. Like the Red Army during WW2, the Klingons would open up a new front on the opposite side of the Romulan Star Empire while Humans, Vulcans, Andorians, Xindi, Tellarites, Trill, Benzites, etc. (and possibly even Ferengi) joined together to attack the main Romulan fleet.

Close quarters

If any remnants of the Romulan attack force reaches Sector 001, they'd be engaged by starships assigned to local patrol as well as reinforcements from nearby sectors like Deneb, Denobula and Andoria. As the Romulan fleet approaches the Sol system, starships and attack fighters would be scrambled from Jupiter Station and the Mars colonies. Then the Romulan ships would need to penetrate the Mars Defense Perimeter sentry pods. And as the last line of defense, the Earth has the Global Security Net, which consistent of unknown planetary defenses but probably includes some orbital weapons and more attack fighters.

The result

Either way, it would be more or less a one-way trip for every Romulan warbird involved and a suicidal move by the Romulan Empire. The Romulans only ever had probably less than 500 D'Deridex heavy cruisers at any time, and that number was reduced to less than 200 by the end of the Dominion War. Even at full strength, committing "hundreds" of warbirds to an incursion into Federation space would leave their empire completely defenseless against the Klingons and any other neighboring powers. Unwilling members of the Star Empire would soon rebel as well, further weakening the Romulans until the entire empire collapsed.

And it's extremely unlikely they would succeed where the Borg and Dominion have failed. So they would effectively achieve nothing and lose everything.

  • One thing on the "War on Two Fronts" is that the Klingons might just decide to attack both the Romulans and the Federation. Granted there was a changling involved, but it didn't take very much for the Klingons to declare war on the Federation during Deep Space Nine.
    – Xantec
    Aug 17, 2013 at 12:25
  • @Xantec: Possibly. It depends on who has control of the High Council. That's the main danger of any such Romulan attack--the political instability it creates and possible shifts in allegiance, rather than the actual Romulan fleet. Aug 17, 2013 at 14:06
  • 1
    So Shinzon's Scimitar warbird could make it all the way to Earth undetected and unopposed?
    – user16416
    Aug 17, 2013 at 18:49
  • 1
    @user16416: As far as Star Trek canon goes, yes--though Geordi never empirically proves that it's impossible to detect the Scimitar. He simply wasn't able to find a way to penetrate its cloak in the allotted time. And being a lone ship rather than a concentrated fleet also helped. Aug 19, 2013 at 7:06
  • 1
    @Xantec Klingons? Ally with Romulans? Incredibly unlikely, especially considering the strongly suspected Romulan support of the Duras Sisters during the Klingon Civil War (they might have even tried this very thing, if they had been on the winning side...)
    – Zibbobz
    May 5, 2014 at 14:03

The federation protects their borders using Gravitic Sensor Nets to detect cloaked ships attempting to cross the border

Gravitic Sensor Nets on Memory Alpha

  • 1
    From the link you provide: It was not considered completely effective, and was eventually supplemented by the tachyon detection grid.
    – bitmask
    Aug 16, 2013 at 14:56

From the top of my head:

At least as far as the TV shows and movies go there is a lot of inconsistency with tracking cloaked ships. Apparently space drives in Star Trek create something trackable ... mostly neutrino emissions IIRC. Therefore you can track about any moving cloaked ship, as long as you look for residual radiation emitting from its engines. This should make anything as big as a fleet easily trackable.

However, it always required some sort of recalibration or extra scan to detect moving cloaked ships. I could never see, why it was always a bit of a break through to do that. One should think once you knew how to beat them ...

  • I don't know what you mean by "space drives", but it is indeed true that matter-antimatter reactors (as used in Federation and Klingon warp drives) release neutrinos. However, Romulan warp drives use a distinct artificial quantum singularity to generate power. Additionally, they have nullifier cores to balance the radiative emissions of the warp drive. Furthermore, as Memory Alpha illustrates, there are a ton of natural and artificial phenomenon that generate neutrinos. So it's not just a simple matter of detecting neutrino emissions. Aug 17, 2013 at 3:00
  • Detection of 24th century cloaked ships usually relies on weaknesses of particular cloaking configurations, such as the subspace variance left by Romulan Warbirds traveling above Warp 6, the incomplete cloaking of other ships moving at high warp, the subspace disturbance created by large fleets of cloaked ships, or concentrated tetryon particles or other emissions when a cloaked ship is nearby, etc. None of these techniques are perfect or foolproof. They require luck/proximity and/or careless enemies and still might not give you the precise location of the cloaked vessel. Aug 17, 2013 at 3:15

The detection of cloaked ship nets are all right ect, but there are few mistakes in that logic...

1st: klingons helping federation, as in dominion they had short war and the new cancelour wasnt a federation friend there is similar possibility that klingons could either help romulans or just attack federation to claim territory from a weak foe (like they did many times) i would actually say taht its 50/50 on that point.

2nd: you presume that romulans launch a whole fleet in 1 place... not logical as most engages are multi targeted to spread chaos, and as we had seen groups of single DD's can easy go undetected through these all defences (it just takes much longer to prepere). Also dont use the DS9 example as possibility to detect rom ships as they could only do that as O'brien knew from future visions that roms will detect and he was searching days to find them (why we dont know why roms were waiting afk). Also as we see in Nemesis the valdores and scimi are 100% non detectable to the most advanced fed ship in 1km range...

3rd: from what i read on alpha roms had lost around 40% of DD's what is a very good outcome considering federation losses. You have to also rememeber that DD's are utility ships (a huge nebula with all 3 pods in one x1,5) but cheaper to produce then galaxy and can probably cripple or destroy galaxy class ships in 1 on 1 run (like shown in TNG when a shot ALONE from main cannon take Galaxy class vessel shields to 30%). Damn it had enough power to actually whipe out a whole starbase. Yes they have weakness because of the huge canon shots for weaker ships but formation runs and cloak kinda pulls it up to some point (and the moment of surprise that in series never was used). Also the new Mogai seems more combat oriented, and it looks like its a version of DD that is pure combat oriented with similar tankyness but way more fire power (the 4 frontal disruptors - where roms didnt want to fire torps - have more effect then every torp and frontal phaser on Enterprise) and around 2x turn rate. So they dont have such little ship weaknes and augmenet the utility DD's very good and probably would hit sovereign class as hard in initial run as DD's did to Galaxy. To it there's also the problem that DD's and Mogais can be mass produced, they seem of similar power to fed TOP OF THE LINE but around 50% as hard to produce - such advantage wins wars.

4th: Federation couldnt even handle the short was vs klingons 1 on 1 where klinks had their army in cardassian space, i wouldnt even dare to say that feds survived Dominion or Klingons, as i wouldnt say they could survive Romulan invasion 1 on 1 (and their suriprise attack because of how spread their forces are - even if they have the largest fleet as they are the largest empire).

The reason why roms dont attack feds is probably is because roms still dont have definitive advantage and thus the outcome isnt rly shure and it could end up in a long and bloody war not beneficial, while there is also the 50/50 risk of who do klinks help. Also there still may be the problem of to low ship diversification (but well we have 2 heavy hitters of witch 1 is utility also but weaker, and scout ships and sci light detector from TNG).

to sum things up... yes cloak is broken OP invention and it shouldnt be made so good in TOS :D, that would make the power balancing for Serier easier and clearer.

  • Welcome to SFFSE! Could you first try to add more of a cohesive structure to your argument? At the moment it is quite difficult to follow. You also supply a lot of opinions here; could you cite sources for your evidence to support this? Thanks Jun 24, 2015 at 23:50
  • These opinions were to the top responce on this site and the sources are: for point 1st: the klingon-federiation war in mid of DS9 and the cancelour that was apointed, with the pressure of federation ignoring the the founders infiltration - echoes from war dont pass by so fast (you never see countries who were at war be 1 month later allies). 2nd: Basics of EVERY war that were lead, or basics in any military book, or for example just read the initial tactics that were used in most prominent wars (WW1,WW2, Desert Storm ect). To it DS9 prometeus episode - 2 DD's are mid in fed space undetected
    – t0ff
    Jun 29, 2015 at 23:32
  • 3rd: But for the D'deridex power like i said, the DS9 episode when they show that the DD's main canon and torps can breach through Star Bases hull with easy if they engage with surprise. youtube.com/watch?v=QQUHJyjlGew (0:30) you can see a DD firing from only 1 main canon taking galaxys shields to 30% (and DD's had more then 1 canon facing frontal - even if the rest were weaker and also torps). About the mogai - nemesis movie (the disruptor main cannon dmg makes way bigger splash on its shields then Sovereigns phasers
    – t0ff
    Jun 29, 2015 at 23:34
  • In that case then, can you add those references to your answer, citing specific episodes where appropriate; it will go through the tour; you'll earn a badge! Jun 29, 2015 at 23:34
  • To it they could take 16-7 hits point blank in 1 arc without exploading but being crippled while Scimitar was shooting to kill them - while trying to disable Sovereign. Sovereing could take around 15 hits from longer range i 1 shield arc in larger time span till it let the dmg to hull what indicates similar shield power and the hits had similar hull effect. What was noticable also was Sovereign even if weaker frontal power (as the mogai/norexan didnt fire any torps as they also wanted probably to salvage some tech from it) had way better firepower aft and sides (just count number of shots).
    – t0ff
    Jun 29, 2015 at 23:38

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