This narrow, safe passage through a perilous area of space was severely polluted by warp emissions.
This article comes from Star Trek Magazine, v. 1, i. 12.
The Hekaras Corridor is a 12-light-year-long plotted route through the Hekaran system, established by the Federation as a safe means of passage though an otherwise dangerous sector. The Corridor is a necessity, as without it starships using warp drive propulsion systems would be unable to navigate effectively due to the unusually intense tetryon field surrounding this region of space. The phased ionic pulse necessary to the warp engine is disrupted by the connecting fields of subatomic particles comprising a tetryon field, and they have an equally disruptive affect on sensors.
The only inhabited planet within the Hekaras Corridor is Hekaras II, and the inhabitants have expressed concerns about the large gravitational shifts experienced throughout the system as a result of continuous use of warp drive propulsion units through the Corridor. The manifestation of problems was indicated by regions of potential subspace instability, which, if they continued to be exposed to warp field energy, would cause ruptures permitting the extrusion of subspace into normal space.
A theory was developed by the Hekaran scientist Serova that this is a cumulative erosive effect with serious side effects, and may lead to subspace rifts; unless warp travel through the Hekaras Corridor ceased, such rifts were inevitable. Putting this theory to the test would require warp levels one million times greater than those emitted by a passing starship.
In 2370, a warp core breach from the explosion of the Federation starship U.S.S. Fleming NCC-2036 ruptured one of the unstable regions, causing a subspace rift of approximately 0.1 light years in diameter. The resulting swirling mass of purple-shaded energy was disastrous for future travel through the Corridor as it emitted extremely high levels of tetryon radiation. The consequent high energy distortion waves generated from within the rift had a potentially devastating effect on starship shields, and although there were areas of stability within the rift, further warp engine activity in their vicinity was not desirable as it might accelerate an already expanding process.
If required, it is possible for a starship to enter the rift by means of a brief high intensity warp pulse from the outside. This permits a two-minute approximation of warp speed once inside; the momentum can be consolidated by steering the ship on impulse power, and allows for the velocity required to escape the rift. But given the potential navigational dangers, and the inability to rely on sensors once within the rift, this is a very risky procedure.
Once caught within the distortion field, a skillful starship crew can maneuver their craft into a position to be able to 'surf' the distortion waves. This can be achieved by phase matching the variance of the ship's deflector shields with the energy and mass of the distortion wave, and thus riding the wave back out into normal space until it dissipates. However, this is only an emergency procedure as it raises the stress factors on the hull beyond acceptable safety limits.
The subspace breach can be avoided by traffic passing through the Hekaras Corridor, but scans have revealed that smaller subspace instabilities have also developed outside the rift. This being the case it was estimated that continued use of the engines would render the area impassable within 40 years.
The worrying effects of the gravitational pull on Hekaras II can be countered by the application of thermal stabilizers, and pervious climatic conditions can be restored through the use of a weather control matrix. Current scientific knowledge, however, has no known method of either resealing the already open rift, or even reducing its size.
Given the ongoing effect caused by warp engines, the Federation has restricted travel through the Corridor to essential traffic, and instituted a limit of warp 5 in all but extreme emergency situations. This knowledge has been shared with all space-faring species in the hope that they will also observe the restrictions. By 2371, StarFleet had introduced a new design of warp engine that does not appear to damage the fabric of space at high warp speeds. The Intrepid-class U.S.S. Voyager NCC-74656 was one of the first starships to make sure of the new design, utilizing variable geometry warp drive nacelles, and similar technology was later incorporated into every new class of vessel designed by Starfleet.