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H2A Out Of Slipspace

Regret's Assault Carrier exiting slipspace near Installation 05.

Slipstream space,[1] slipspace,[2] subspace,[3] or Shaw-Fujikawa space[4] refers to the eleven non-visible infinitesimal dimensions used for faster-than-light travel.[5] Making a transition from one place to another via slipspace is known as a "slip" or "jump."

Slipspace is a hyper-compressed multidimensional space separate from our own reality.[6] To the human eye, slipspace appears pitch black, because there is nothing in the visible spectrum to see.[2][note 1]


This section requires expansion.

In 2291, Tobias Shaw and Wallace Fujikawa were the first humans to successfully create a device that could transition normal matter into slipstream space, the Shaw-Fujikawa Translight Engine.[7]


Slipspace can be thought of as our detectable universe (which, technically, it is) but with a greater number of dimensions. Our plane of existence is thought to have four dimensions (finite 1 dimensional points, planar dimensions as direction, third dimension as form and mass, and time as the movement or vibration of said dimensions), but Slipspace is an eleven-dimensional spacetime.[5] Slipspace is currently theorized (in 2552) as a "tangle" of our plane's dimensions, rather like taking the classic "flat sheet" used to represent gravity (even though its a 3 or 4 dimensional concept) and crumpling it up into a ball, thereby creating extra dimensions and shorter spaces between points. The slipstream also possesses different laws of physics than our "normal" universe, although some basic ones, such as energy transfer and momentum, remain the same.[8]


Seperatist fleet ark

The Covenant Separatist's Fleet of Retribution coming out of Slipspace over Installation 00.

To travel through slipspace, courses are plotted by navigating superfine patterns of quantum filaments. Then when inside slipspace, the ship must navigate various layers of slipspace until the ship reaches a locus that intersects with the intended destination.[6]

The activation of a slipspace drive creates a portal between realspace and slipspace. Less refined drives can make entrances and exits more dangerous.[6] While traveling through slipspace, ships accrue something called Reconciliation Debt.[9]

Slipspace Capable Ships[]

UNSC Infinity Slipspace

UNSC Infinity and its escort entering Slipspace.

Entering and exiting the slipstream is normally only attempted by ships of large mass, their gravity wells stabilizing slipspace to a degree that allows safe passage. Small ships, such as dropships, do not possess the same gravity and are placed under considerably more stress than a warship, able to crack the hull and buckle reinforcing struts.[10] It is not impossible, and UNSC slipstream monitoring probes make the transitions all the time, but require heavy reinforcement to survive the stresses, and are unmanned, having no need to protect internal occupants.[11] Specialized craft like Long Range Stealth Orbital Insertion Pods can make the transition, but are still an extremely uncomfortable ride.[12] A Slipspace-to-normal space transition has been successfully attempted by a Spirit dropship, but it had been extensively equipped with Titanium-A battleplates, lead, and carbon-molybdenum steel I-beams. Slipspace is now capable with small ships such as the Pelican.

In addition, Cherenkov radiation is emitted by fissile materials, including a ship's reactor and nuclear armaments, upon entry and exit of the dimension, requiring all Slipspace-capable craft to be fitted with lead shielding as radiation protection. Slipspace drives can only be equipped on large ships, as the stress that the constantly fluctuating Slipstream exerts is considerable and can tear a small craft, such as a dropship or star fighter, completely asunder.[11]

Because the Slipstream is constantly shifting, and its laws of physics are different to our own, the magnetic coils of Slipspace drives drift out of phase when entering and leaving a Slipspace field, requiring constant maintenance. During the 2490's, technicians had to manually repair Slipspace drives, exposing themselves to the Slipstream and occasionally suffering injury, death or simply disappearing.[13] Mechanical failures like Slip Termination, Preventable, or STP, can also occur with Slipspace drives, usually resulting from poor maintenance.[14]

Travel Times[]

Slipspace travel has very little, if any connection to realspace distances and velocities. More often, trips are influenced by currents and other temporal variations. As well, some routes have different confluences that can affect travel time too. Traveling the same, heavily monitored route does not guarantee the same travel time. Examples of the discrepancy between distance and travel time can be seen with the Epsilon Indi system, which takes months to reach despite being at Earth's doorstep, and Installation 00 which only takes a few months despite being beyond the edge of the Milky Way galaxy.[6]

Some "short" jumps routinely take up to two months, and "long" jumps can last six months or more for the crew. The time it takes to normal-space observers, however, varies substantially - one cannot depend on the same amount of time passing in Slipstream space and normal space. These variations are typically measured in weeks or months, and are unpredictable. A fleet that transitions to Slipstream space at the same time may or may not transition back to normal space at the same time. Furthermore, if ship A and ship B both enter Slipstream space at the same time and exit at the same time, the crew on ship A could have experienced a longer journey subjectively, and the crew of ship A could, in fact, be a week older than that of ship B despite appearances in normal space.

When ships jump into Slipspace, they need to reach a Safe Slipspace Entry Point, or SSEP, where it can be ensured they won't drag anything from normal space into the slipstream as the ship initiates the transition.[15] In addition, star systems have specific Slipstream space transfer points known as Interstellar Jump Points, or IJPs, where it is safe to initiate slipspace transition.[16]

The Covenant Empire also utilize the same eleven dimensions of Slipstream space for travel, though the means they use to make the transition are most likely different than those of the humans because of their markedly "faster" journeys from point to point.


H2A Slipspace

The Solemn Penance entering slipspace in Mombasa.


Solemn Penance inflicted enormous damage on New Mombasa by jumping to slipspace above it.

Nmoe slipspace

The results of Regret's carrier entering Slipspace over New Mombasa.

Gravitational fields of significant size, such as those generated by a planet, affect the superfine quantum filaments that the Shaw-Fujikawa Translight Engine must use to calculate an entry point to the slipstream, and UNSC calculations are unable to offset this effect.[17] Covenant drives, in turn derived from Forerunner technology, have a much higher resolution of the filaments, and use more accurate calculations, and though the Covenant do not use this ability, are capable of making slipstream transition in and out of a planet's gravity well. Indeed, while using the captured Ascendant Justice to make a Slipspace jump within Threshold's atmosphere, Cortana remarked that "It was as if she was blind before."[17] After observing this innovation, a Covenant AI managed to leak the data out to the rest of the Covenant in a transmission. During the Battle of Mombasa, the Prophet of Regret used this newfound knowledge to transition into Slipspace while directly over New Mombasa in Earth's gravity well, damaging the city and causing the weakening and eventual collapse of the Orbital Elevator there.[18] These events show that, while the Covenant often cannot innovate their own solutions, they are quick to adopt any practice that increases their battle prowess.

Entering slipspace from the gravity well of a planet was rarely attempted, by either the UNSC or the Covenant. The effect of gravity upon the creation of a slipspace entrance usually collapsed UNSC-generated holes, and the same was assumed to be true for Covenant technology. The UNSC Everest, however, is thought to have attempted it under the orders of Admiral Cole, during the Battle of Psi Serpentis, to escape certain death as Viperidae ignited into a brown dwarf star. In 2552. The flagship Ascendant Justice was also able to escape from a gas giant's gravity well after Cortana realized that it had a far higher resolution of the quantum filaments that allowed a transition, and she was able to compensate for the gravity. Subsequently, the ability was transmitted by a Covenant AI, and the Prophet of Regret was later able to use it to perform an in-atmosphere slipspace jump to escape Earth, with the resulting shockwave dealing devastating damage to the city of New Mombasa. Slipspace jumping inside an atmosphere, however, is extremely dangerous to the surrounding people and objects. When a ship transitions into normal space in-atmosphere, the air that was there is pushed aside, causing a massive shockwave centered at the ship. If a ship transitions to Slipstream space inside an atmosphere, on the other hand, it leaves an empty space that air quickly rushes to fill, causing an implosion.


Travel routes were known to develop in slipspace. Human Inner colonies were known to be along low-energy routes, while the Outer Colonies were at the ends of most routes.[19]

One route that was discovered following the Human-Covenant war, connected the Sol system and the Epsilon Eridani system, but placed smaller planets and systems, like Ruthersburg, within its path.[20]


A "Slipspace Wake" is a phenomenon occurring for some time after a ship has made a slipspace transition. When another, slower ship encounters a slipspace wake, they will be pushed to the speed of the ship that left the wake, thus propelling them through Slipspace at the same velocity. The UNSC Dusk took 2 weeks to get to Installation 05 via the Prophet of Regret's Assault Carrier's weakening "wake,"[21] but came back to Earth within hours by following the Forerunner dreadnought's wake.[note 2] They also used this to follow the Bloodied Spirit and get to a battlegroup they needed to join much faster.

Ships that do not have slipspace drives can follow in the wake of other ships as well.[6]


Slipspace velocities are generally dependent on the ship's momentum on transition, as the Slipspace drive itself does not generate thrust.[22] As a result, ships that are faster in normal space, such as corvettes, usually travel faster than others in the Slipstream as well.

Human Slipspace velocities are far slower than those of the Covenant, traveling at approximately 2.625 light years per day.[note 3] One example of the differences between speeds is comparing the Covenant carrier Ascendant Justice with the UNSC Halcyon-class light cruiser UNSC Pillar of Autumn. It took several weeks for Pillar of Autumn to get from Reach to Installation 04, yet Ascendant Justice could get from Reach to Installation 04 within thirteen hours.

Though the Covenant use a modified version of Forerunner systems, true unaltered Forerunner slipspace technology has only been observed in the form of the Artifact transporting UNSC and Covenant vessels from Earth to the Ark. Additionally, while a Covenant Assault Carrier could reach Earth from Delta Halo in thirteen days, a distance of approximately 11,856 light-years,[note 4] the Forerunner dreadnought took only five days to travel the same distance, giving a speed of approximately 98.8 light-years per hour.[note 5] Given the fact that Covenant understanding of Forerunner technology is comparatively primitive, the ship may have been capable of much higher velocities.


Main article: Slipspace Anomaly

In rare cases, various types of anomalous phenomena occur in slipspace. These may be caused by specific artifacts or devices. The effects of these anomalies are diverse, but often harmful. The Forerunner Crystal found on Reach was capable of creating a distortion in Slipspace, but it also made massive amounts of radiation.

In addition to temporal anomalies, UNSC ships aren't able to jump with exact precision. A ship may transition back to normal space millions of kilometers from its intended destination.[23] As a result, UNSC ships often transition in and out of slipspace outside star systems, far from any gravity wells or celestial bodies. In-system jumps are also not generally attempted by the UNSC due to the dangers present.[24] A notable exception of this was during the Battle of Psi Serpentis, when Battle Group India, under command of Admiral Preston Cole, performed an in-system jump. Even though Cole had made thorough calculations for the jump a week in advance, a part of the battle group scattered, reappearing outside the main group.[25] Another example is the UNSC In Amber Clad, that was able to make a successful precision jump into High Charity. This may be due to an improvement on the ship due to the recent capture of Covenant Slipspace technology, the Gravemind adjusting it or simply luck.[26] These imprecise jumps were remedied after the war with the research of captured Forerunner drives.

A slipspace accident caused a UNSC AI to be transported from the year 2552 to the year 2004.

Living Beings and Biological Matter[]

Direct exposure to the Slipstream is incredibly dangerous. People traveling on a Slipspace-capable craft can experience a range of symptoms, from nausea, to heart failure or even death. Even more uncommon, but still known to happen, is the total disappearance of a person while in the slipstream.[27] In some rare cases, having a specific Forerunner object such as the Forerunner Crystal onboard may cause the ship to be in an anomalous dimension within Slipspace.

Slipspace travel is dangerous due to the high level of radiation encountered during the trip, which can be extremely hazardous to the crew. This is negated by the use of Lead Foil in UNSC ships, which absorbs the radiation. Fissile materials also emit radiation (specifically Čerenkov Radiation, emitted when particles travel through a medium at a faster rate than light travels in that same medium.) upon exiting Slipspace; this is not harmful to humans, however it does make emerging from Slipspace very noticeable. It is not known how the Covenant deal with radiation, but it is presumed that either they also utilize a shielding material, or with their improved Slipspace technology and Energy shields, it does not affect them at all.[12]

Artificial Intelligence[]

Dr. Catherine Halsey theorized that scientists could use slipspace to effectively remove the memory issue that creates Rampancy in Smart artificial intelligence. It would also give that Artificial intelligence faster-than-light processing speeds.[28]




The Shaw-Fujikawa Translight Engine allowed human ships to tunnel into Slipstream space, called by technical humans "Shaw-Fujikawa Space,"[4] after the scientists who proved its existence. It generates a resonance field, which when coupled with the unusual physics of the Slipstream, allows for dramatically shorter transit times between stars; however, scientists note an odd "flexibility" to temporal flow while inside the Slipstream. Though no human scientist is sure why travel time between stars is not constant, many theorize that there are "eddies" or "currents" within the Slipstream — there is generally a five to ten percent variance in travel times between stars. This temporal inconsistency has given military tacticians and strategists fits, hampering an uncounted number of coordinated attacks. Shaw-Fujikawa engines allow ships to leave normal space and plow through Slipspace. Slipspace drives use particle accelerators to rip apart normal space-time by generating micro black holes. These holes are evaporated via Hawking radiation in nanoseconds. The real quantum mechanical "magic" of the drive lies in how it manipulates these holes in space-time, squeezing vessels weighing thousands of tons into Slipspace.[29]


During the Battle of Shield 0459, UNSC Spirit of Fire sacrificed its slipspace drive to turn the world's artificial star into a supernova. Once the drive was detonated, the resulting supernova swiftly destroyed all the ships, a Flood outbreak, and the entire shield world itself.

During the Fall of Reach, the drive of UNSC Savannah was mounted on a D77-TC Pelican and "fired" from inside the Long Night of Solace. It ripped the ship into two.[30]


The Covenant have a very finely tuned version of this technology, far superior to the UNSC Shaw-Fujikawa Translight Engine. Instead of simply tearing a hole into Slipspace, Covenant Slipspace drives cut a very fine hole in the fabric of space-time and slips into Slipspace with precision (much like a scalpel compared to a butcher knife). It exits with the same pinpoint accuracy, takes less time during travel, and is able to plot a course with error not exceeding an atom. This is why in battle Covenant ships are able to slip by human defenses by using slipspace.[31] Standard Covenant tactics include using short Slipstream jumps to gain positional advantage and surprise other ships, in addition to avoiding incoming ordnance. The Covenant's superiority in drive technology (combined with differing weapon technology) allows a small number of Covenant ships to effectively engage a much larger UNSC force. Missiles, especially, can be defeated by a brief Slipstream jump, as they cannot track through Slipstream space.


Nomis78 opened gateway

A Forerunner Slipspace portal.

The Forerunners had a far greater understanding of Slipstream space, with the abilities to travel nearly instantaneously over galactic distances, to disrupt slipstream travel from normal space, to create bubbles of Slipstream space, accelerating time, slowing time considerably inside (or even a complete time lock) while keeping the contents of the bubble visible in normal space, to store considerable mass and volume in Slipstream space stably for thousands of years and potentially for all of time, and to transition matter from normal space to the inside of a construct in Slipstream space without requiring the construct to transition back to normal-space. They were apparently also able to send several objects into Slipspace and have them exit in different locations.[32]

The understanding of slipspace by the Forerunners allowed them to create the Slipspace Field Pods. Essentially a Forerunner equivalent of Cryo-chambers, effectively preserving a living organism inside a Slipspace field. In addition, the Forerunners had the ability to construct weapon systems that could fire into Slipspace and affect targets in normal space or within Slipspace. This is demonstrated by the galaxy-wide effects of the Halo Array, as well as in smaller scale by Line Installation 1-4.[33]


The Forerunners were somehow capable of advanced message carrier waves in slipspace. This way, messages and memorandums could travel at great speeds throughout the Forerunner Empire. Cortana was able to use this technology to declare codes Bandersnatch and Hydra during the Battle of Earth and the Battle of Installation 05 in close-knitted timing and symmetry.

The closest technology the UNSC has been able to create like this is the Slipspace COM launcher. Even then this technology is limited as there were only three in existence before 2552: one on Reach, one on Onyx and one on Earth. As of the conclusion of the Human-Covenant war, both the devices on Reach and Onyx have been destroyed, with the fate of the Earth device unknown.

Most human communiques are actually carried on the shipboard memory of starships such as freighters. On the other end of the ship's slipspace journey, the message is relayed to the intended recipient.[34] In addition, human civilians are known to use a form of communication referred to as "slipstream packets."[35][36] Their exact nature is unknown, but the term may refer to the method of carrying messages on starships' computers. Another method of interstellar communication also exists, known as the Slipbeacon.[33] After the war humans were able to use forerunner technology to communicate even in slipspace.

Real World[]

Slipspace fills a common niche found in most space science fiction series/films, allowing ships to travel vast distances in a small amount of time. Though other series use different methods, it is most similar to hyperdrives, which similarly burrow into other (albeit more stable) dimensions where faster-than-light (FTL) travel without the relativistic side effects is possible. Other series use different methods, allowing actual FTL travel in normal space, or instantaneous teleportation, but the principles still follow a similar trend.

Slipspace can be likened to the recent discovery of matterwave transport without transit. In this process the 7 hidden spatial dimensions, 3 known spatial dimensions and the 1 time dimension appear to collapse into a singularity to an outside observer. But in reality, this is only an illusion. In this type of field, relativity predominates, for instance the reality is dependent on the radial displacement from the source that generates the field. At small distances, reality is relatively intact. The further away from the field source, the less sense it makes to talk about reality; a cause can occur after an effect, time has no linear flow. Nothing has a definite momentum or velocity. Objects can occur at multiple positions simultaneously. When an object enters a field, it produces a burst of neutrinos, antimatter and other types of radiation.

The concept of using an alternate dimension with different laws to travel faster than general relativity allows was first posited as the Minkowski Space Theory. Slipspace is also similar to a controversial theory called the Heim Theory.




  1. Halo Wars: Genesis depicts slipspace as resembling purplish nebulae; however, this can be considered an oversight or an artistic liberty for the sake of presentation.
  2. It is never directly stated that the wake the Dusk followed was left by the Forerunner dreadnought; however, it is implied on page 289: "The Dusk's journey back to Earth had occurred in record time. They had caught a wake in slipstream space, one indeterminably larger then the Covenant wake they had followed." This creates an inconsistency with later canon, as in a timeline released by Bungie, it is revealed the the Keyship took five days to reach the Sol System instead of a few hours.
  3. Velocity=Distance/time (V=10.5 light years/4 days=2.625 l/d). This was determined through a direct course from Reach to Earth following the Fall of Reach in "Halo: First Strike."
  4. Distance=VelocityxTime (312 hours x 38 lightyears per hour=11856 lightyears)
  5. V=D/T (11,856 lightyears / 120 hours = 98.8)


  1. Halo: The Fall of Reach, page 13
  2. 2.0 2.1 Halo: The Fall of Reach, page 15
  3. Halo: Combat Evolved - Level: The Pillar of Autumn
  4. 4.0 4.1 Halo: The Fall of Reach, page 141
  5. 5.0 5.1 Halo: First Strike, page 87
  6. 6.0 6.1 6.2 6.3 6.4 Halo: Warfleet – An Illustrated Guide to the Spacecraft of Halo - pages 10 & 11
  7. Halo 3 - Map: Orbital
  8. Halo: Ghosts of Onyx - page 55
  9. Halo: Warfleet – An Illustrated Guide to the Spacecraft of Halo - page 92
  10. Halo: First Strike, page 296
  11. 11.0 11.1 Halo: First Strike, page 289
  12. 12.0 12.1 Halo: Ghosts of Onyx, page 13
  13. Halo: Ghosts of Onyx, page 146
  14. Halo: Contact Harvest, page 24
  15. Halo: Contact Harvest, page 34
  16. Bungie.net - Halo: Reach Project Page
  17. 17.0 17.1 Halo: First Strike - page 85
  18. Halo 2 - Level: Metropolis
  19. Halo: Warfleet – An Illustrated Guide to the Spacecraft of Halo - page 91
  20. Halo Waypoint: Canon Fodder - Buzz Generating
  21. Halo: Ghosts of Onyx, Chapter 22, page 186
  22. Halo: Contact Harvest, Chapter 1, Page 23
  23. Halo: The Fall of Reach, page 136
  24. Halo: The Fall of Reach, page 104
  25. Halo: Evolutions - Essential Tales of the Halo Universe, The Impossible Life and the Possible Death of Preston J. Cole, page 477
  26. Halo 2 level Gravemind
  27. Halo: Contact Harvest, page 175
  28. Halo: Reach Legendary Edition - Bonus Item: Dr. Halsey's Personal Journal, December 25, 2534
  29. Halo: Ghosts of Onyx - page 53
  30. Halo: Reach - Level: Long Night of Solace
  31. Halo: First Strike, page 86
  32. Halo Legends - Origins
  33. 33.0 33.1 Halo: Blood Line - Issue 1
  34. Halo: Contact Harvest, page 35
  35. i love bees: week6_subject3.wav
  36. Axon Clips: Chapter 6