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UNSC Behind in Twilight
UNSC Behind in Twilight (FFR-002)
Production information

Reconnaissance frigate



Modified by


Technical specifications
Modified systems

Extensive modifications; stealth capacity and WMD capacity, reductions in armor, weaponry, velocity, and manueverability


750 meters

Maximum acceleration


Maximum speed (Space)


Maximum speed (atmosphere)

Atmospheric operations contraindicated

Engine unit(s)

Tritium / plutonium fusion-fission process


Radio-absorbant thermoplastic alloy

Sensor systems

Extensive signals (SIGINT) and image (IMINT) reconnaissance dedicated sensor suite


Extensive electronic warfare (ECW) and electronic countermeasures (ECM) dedicated suite

  • Gauss Battery (1)
  • Archer missile pods (6)
  • Point defense cannons (4)
    • Firing Arc: Forward (2)
    • Firing Arc: Aft (2)
  • Weapons of mass destruction
    • Thermonuclear capability
    • Biological capability
    • Chemical capability




  • Reconnaissance-in-force
  • Fleet intelligence gathering
  • Deep penetration raiding
  • Deployment of weapons of mass destruction (WMD)

2541 (ONI Deep Space Naval Observatory)

Earliest sighting

Tantalus (2542)


UNSC Office of Naval Intelligence

Known commander(s)

Colonel James Ackerson

"Colonel Ackerson, coming all the way out here on his private ship? One would wonder of the merely coincidental vanishing of a MEDCORPS investigatory committee on Tantalus's surface and the proximity of James Ackerson overhead, aboard an invisible ship."
―Wakes to Ackerson

The UNSC Behind in Twilight (FFR-002) was a stealth reconnaissance frigate of the UNSC Navy, permanently detached to the UNSC Office of Naval Intelligence, Section One (UNSC Fleet Intelligence) and Section Three. Its hypothetical design was known as WHITE SANDAL, and it would be the product of the academic think tanks RIVER HEDGE and MARBLE COURT, and it would serve as the archetypal prototype and predecessor to the "stealth reconnaissance frigate" (FFR) model of UNSC warships.

Technical Specifications


The UNSC Behind in Twilight sports prowler-like stealth characteristics, one of the only capital vessels of the UNSC Navy to ever sport dedicated stealth characteristics, and it is technically related to the UNSC Point of No Return and the UNSC Midsummer Night, two other frigate-tonnage UNSC warships that received extensive modifications to increase surreptitiousness in operations and to allow small capital ships to undergo deep-penetration reconnaissance in force (RIF) operations, allowing for armed warships to be able to destroy identified enemy targets, rather than the lightly-armed smaller prowler vessels typically used for such missions, which carried insufficient munitions to destroy most targets they identified and characterized. Besides the aforementioned Point of No Return and Midsummer Night, few other examples of capital warship-scale stealth technology exist within the UNSC Defense Force, although after the closure of the Human-Covenant War, Section Three was rumored in some circles to be associated with MARBLE COURT, a secretive ONI theoretical design program to efficiently scale the production of stealthed warships. The purpose of such warships, and their existence in the post-War truce and peace, remain ambiguous.

Stealth Characteristics

The UNSC Behind in Twilight sports particular and eccentric modifications to ensure its stealth capacity. It was designed to present a minimal radar cross-section, and in contrast to the blocky and inelegant main-stream guided missile frigates that populate the UNSC Navy, such as the UNSC In Perfect Weather, the Behind in Twilight has a severely-reduced mass which is centered on the midsection, and it is almost phallic and needle-like in appearance, with a longer keel length than a regular frigate, but with a much lighter mass and bulk; the mass is significantly reduced by low-density thermoplastic metals that plate the vessel's hull, giving it radio-absorbance to absorb inbound radars and also making it significantly lighter, although at a heavy cost in defenses—the Behind in Twilight completely lacks radio-reflective Titanium-A battleplate, meaning that its hull can be breached even by a glancing pulse laser or a nearby Archer missile detonation. The vessel, despite its gaunt and linear appearance, is highly angular, and its slanted external surfaces were mathematically modeled to give the highest probability of deflecting away electromagnetic waves that can't be absorbed by the stealth plating. Thus, the combinatorial effect of its electromagnetically-absorbent plating and its acutely-angled surfaces leads to high directivity and low reflectivity, resulting in a near-background radar return when the Behind in Twilight is actively scanned, essentially making it invisible to all radar and audio spectrum electronic sensors. Furthermore, the Behind in Twilight incorporates a highly-efficient cryogenics system that circulates with multiple redundancy across all compartments, and residual heat is radiated to an aft cryogenics dump, which is periodically purged to space in "clear zones" with no enemy activity, allowing for the periodic dispersion of all the heat that is not absorbed by the primary cooling system; this gives the frigate an extraordinarily low infrared profile, even against thermally-hot contacts, such as a planet or a star. The Behind in Twilight also ensures that its position is not compromised by internal measures; the number of electrostatic surfaces in the vessel is limited, and a conductive massive "Faraday shield" that percolates across the internal superstructure diffuses any external radiation. The Behind in Twilight is almost exclusively equipped with tight-beam communications systems which linearly transmit communications, making its transmissions uninterceptable unless the intercepting array is on the exact linear trajectory of the transmission. Furthermore, the Behind in Twilight normally operates under EMCON (electronic containment) stealth protocols, even in "friendly" UNSC space; all communications outgoing from the Behind in Twilight must be personally authenticated by the biometrics of the vessel's captain or communications officer, avoiding possible mutiny and averting the tragedy of the UNSC Midsummer Night, whose expensive stealth characteristics were compromised on a deep reconnaissance operation when a mutinous officer onboard signaled rebel forces the frigate's location.

The Behind in Twilight also maintains extensive electronic countermeasures (ECM) that are designed to defeat highly advanced counter-stealth radars that can calculate the frigate's position based on its partial radar footprints, ensuring the frigate's stealth capacity even to the most sensitive and technologically-advanced sensors. Furthermore, the vessel boasts electronic warfare systems that are used for remote computer warfare to infiltrate hostile electronic systems, as well as to jam enemy communications and radars prior to an attack, "blinding" hostile forces.

Limitations and Disadvantages

The Behind in Twilight's stealth capacities makes it an extremely difficult vessel to handle. The frigate's engines have dramatically reduced thrust because they are based on tritium (3H) and plutonium; two radioactive elements which emit alpha and beta radiation, respectively, which are energized electrons with low penetrativity and can be easily masked by a relatively thin aluminum-lead alloy shielding, maintaining the EMCON of the Behind in Twilight. This usage of less-efficient radioactive fuel rods, however, leads to decreased thrust and maneuverability in deep space, making the vessel one of the slower warships of the UNSC Navy for its tonnage, despite its low density. Furthermore, the vessel's drive efflux is darkened and baffled, making its contrails invisible, but at the cost of maneuverability. The frigate's stealthed hull, which is malleable by heat and extreme conditions, and also its airframe, which is extraordinarily unwieldy because of the frigate's awkward profile and canted surfaces, almost makes it unsuitable for atmospheric operations except in the most urgent of circumstances, where the frigate risks melting its hull in atmospheric re-entry and also fatally losing aerodynamic control because of its curious airframe.


Furthermore, the frigate has limited onboard armaments because of its complex internal systems, electronics, and cryogenics, which take up a significant amount of space; furthermore, all externally-carried weaponry would fatally compromise the Behind in Twilight's specially-designed angular external structure. However, the MARBLE COURT design team strongly affirmed that the frigate had to have a minimal armament onboard to maintain a reconnaissance-in-force (RIF) capacity. A full-sized Magnetic Accelerator Cannon (MAC) was deemed unfeasible, because the residual magnetism and polarity of its superconducting ceramic coils would compromise EMCON. Thus, a small-scaled and cut-down version of a MAC cannon, the Gauss Battery, was installed, with extreme metallic and non-electrostatic shielding to ensure that when resting, it could not compromise stealth and also interfere with other onboard electronic systems. Four point-defense cannons have been cautiously installed, two with forward fields of fire and two with aft fields of fire, to ensure an anti-fighter capacity, and also to destroy any inbound missiles that are not jammed by the extensive electronic warfare equipment. The vessel is also stocked with six retracted Archer missile pods, giving it a very limited ship-to-ship warfare capacity. However, the retarded conventional armaments of the Behind in Twilight are not its primary striking force; instead, it is an exclusive weapons of mass destruction (WMD) deployment platform. It has a specialized internal compartment that is heavily radiologically-shielded and maintained under negative air pressure that is a hold for an unknown number of various weapons of mass destruction (WMD); the Behind in Twilight maintains a potent thermonuclear, biological, and chemical (NBC) strategic force.

Needless to say, the usage of an invisible vessel armed with WMDs prowling under electronic containment in UNSC space during the post-War peace has raised many concerns amongst the UNSC brass.

The Behind in Twilight is rumored to also have a limited onboard fighter-carrier capacity, and certain crew members report that they have seen craft of unknown configuration painted in black in a hangar bay hidden away on the frigate.

Operational History

Human-Covenant War

On occasion, during the Human-Covenant War, the UNSC Behind in Twilight served as Colonel James Ackerson's personal vessel for his more sensitive activities, and this unseen frigate would become a perfect way to mask his whereabouts and goings. In August 2542, Ackerson would take the Behind in Twilight to Tantalus to personally oversee the UNSC Medical Corps ethics investigation of an ONI bioengineering facility that Ackerson was using to produce the illegal mutagenic small-molecule, 009762-OO. When UNSC Naval Special Warfare sniper Wakes cleanly and permanently ended the investigation on Ackerson's orders, Wakes had the opportunity to meet Ackerson aboard the Behind in Twilight, where he earned Ackerson's respect and a transfer into Section Three.[1]

Post War

The UNSC Behind in Twilight would later become associated with the PATRIOT / FORECAST initiatives and Chief Petty Officer Kimberly Ivy Blackburn would be stationed aboard this vessel for an unknown span of time.[2]

Behind the Scenes

  • The UNSC Behind in Twilight is named after a phrase in Erasmus Darwin's posthumous epic poem, the Temple of Nature, published in 1802, where Erasmus would foreshadow the Theory of Evolution proposed by his grandson, Charles Darwin. The exact line is as follows; "Behind in twilight gloom with scowling mien, the demon pain, convokes his court unseen".


  1. Common Denominator novelization, prologue
  2. User:RelentlessRecusant/Halo: Vector
Frigates UNSC Angels Fall First · UNSC Beckon Dusk Forth · UNSC Behind in Twilight · UNSC Beneath Shoreless Waves · UNSC Beside Aegean Wave · UNSC Beyond Veil's Azure · UNSC Breathe Ethereal Gales · UNSC Convoke Court Unseen · UNSC Excelsior · UNSC Glorious · UNSC In Perfect Weather · UNSC Memory of Harvest · UNSC Midsummer Night · UNSC Point of No Return · UNSC Repulse · UNSC Strikefast · UNSC Stymphalian · UNSC Valkyrie's Wing · UNSC Wipe Your Tears
Destroyers UNSC Arbor Vitae · UNSC Peacekeeper · UNSC Thunder Break
Cruisers UNSC Adamantine · UNSC Adorn Ebon Throne · UNSC Cydonia · UNSC Mediator · UNSC Miranda Keyes · UNSC Valorous · UNSC Vishnu
Carriers UNSC Meridian Rays
Corvettes UNSC Apache · UNSC Centaur · UNSC Deterrent · UNSC Flurry · UNSC Speed of Sound · UNSC Thunderstrike
Prowlers UNSC Bend Sinister · UNSC Calyx of Night · UNSC Clairvoyance · UNSC Ether-à-go-go · UNSC Lost a Fin · UNSC Shade
Stations ONI Deep Space Naval Observatory · UNSC Singapore Station · Spirit of Progress
Vessel Classifications Stealth Reconnaissance Frigate · Sojourn-class battle cruiser
Other UNSC Atlantis · UNSC BC-5821Z
Commands UNSC Second Fleet · UNSC Fourth Fleet
Formations CAM-327-17 Task Force · Task Force Gamma
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