Prowler

This article is about stealth ships used by the United Nations Space Command. For the ground vehicle used by the Jiralhanae and the Covenant, see Qavardu Workshop Prowler.

The prowler UNSC Red Horse.

Prowlers, sometimes nicknamed "bats" by UNSC personnel, are a specialized form of stealth-capable corvette within the UNSC Navy. Prowlers are used by the UNSC Navy for stealth infiltration/exfiltration, electronic intelligence gathering, and minelaying operations. Prowlers are exclusively operated by Office of Naval Intelligence personnel serving under the Prowler Corps. Most prowlers are designated with the hull classification symbol PRO, followed by a numeric designation.

The Covenant and its remnants do not seem to operate many direct analogues to prowlers in their respective fleets, due to the Covenant's broader focus on multi-mission capabilities. While they do maintain intrusion corvettes and an unidentified stealth vessel for broadly similar work, stealth shrouds are a relatively common fixture on several otherwise non-stealth warships such as the Ceudar-pattern and Makar-pattern corvettes.

Overview

Role

The prowler's primary role is to stay hidden while safely gathering battlefield intelligence, avoiding direct combat due to its light weapons and armor. Because of their tactical value and potential to change the outcome of any given combat situation, every UNSC battle group has at least one prowler assigned to its ranks. The prowler's standing orders to observe and record, even in the face of UNSC defeat, mean that the ships are explicitly ordered to ignore lifepods and rescue beacons.

The prowler's only combat role, besides active combat monitoring and recording, is discreetly laying cloaked fields of Hornet and Moray nuclear mines in orbital regions. They may also be used to drop slipspace guidance beacons in advance of a large UNSC fleet movement, allowing a given fleet to execute in-system jumps with much more precision than they may otherwise be able to. In addition, these covert roles mean that the ships are also well-suited to ferrying ONI strike teams and cargos of nuclear weapons behind enemy lines, to covertly plant in heavily-defended staging areas and invasion beachheads. Unfortunately, these missions were nevertheless typically one-way. Other prowler roles include transportation for high-level commanders and prisoners.

Design details

Prowlers are on the smaller end of the size spectrum of human starships, typically ranging a few hundred metres in length or less. The Sahara-class heavy prowler is the largest conventional prowler design operated by the UNSC, and only measures up at 281 meters (922 ft)—barely more than the Gladius-class heavy corvette. Indeed, prowlers are low-profile ships built based on corvette design principles, and are considered slow, underarmoured and underarmed for conventional fights. The small nature of prowlers serves to enhance their stealth capabilities, by presenting a smaller radar cross-section and less area for thermal emissions to radiate from. An exception to this rule is the comparatively gargantuan Point Blank-class prowler; informally referred to as a "stealth cruiser" due to its size, the Point Blank measures up at 485m in length—equivalent to a Halberd-class light destroyer and twice the size of even the already-noteworthy size of the Sahara-class. Point Blank-class ships tend to serve as command-and-coordination centres and motherships for smaller prowlers on longer-ranged expeditionary strikes.

Prowlers may be fitted with EMP dampers which isolate the ship's electronics in the event of electromagnetic pulse strikes.

Aside from the more high-end stealth systems discussed below, prowlers may also be disguised as high-end civilian yachts, and often feature unassuming names such as the Lark, Applebee and Circumference.

Stealth systems

Passive stealth systems

Prowlers avoid detection through the use of physical features designed for low observability, low-profile sensor systems, and an array of stealth systems intended to mask the ship from both visual and sensor detection. Prowlers typically rely on passive stealth systems to remain undetected; ship designs employ techniques such as breaking up the thermal emissions via use of meta-materials in the hull coating known as Stealth ablative coating to break up the ship's radar signature.

Active stealth systems

Prowlers may also employ expendable stealth consumables such as heat sinks designed to defer the release of thermal emissions, flares and deception jammers. These systems are typically fired out of the ship, and are thus primarily employed when stealth has failed. Prowlers must have the capability to hide even from their own allies to avoid being tracked in the event a UNSC ship fell into enemy hands.

Many of the aforementioned standard features were first tested on the Chiroptera-class subprowlers in the 25th century, and would later go on to become standard features in successive ONI designs. However, Prowler designs deployed prior to the Human-Covenant War did not employ particularly effective active camouflage systems, and instead relied on the aforementioned passive methods to remain undetected. Future enhancements during the war and the successive reverse-engineering of Covenant and limited integration of Forerunner technology such as bafflers did allow for more active technologies to become standard by the late-war era and as of 2558, all prowlers employed some form of active hull camouflage technology.

PRO-49776 exits its active camouflage field.

These more active forms of hull stealth technology encompass a variety of methods; a common form of programmable optical hull camouflage is the texture buffer, which serves to line the ship with the aforementioned photoreactive coating and allow the surface to take on similar colouration as objects behind it such as planets. However, even these texture buffer systems were crude in comparison to Covenant active camouflage, operating on a seemingly similar principle as the SPI armor's photoreactive panels. For example, the UNSC Wink of an Eye's stealth coating was fairly unstable, making the ship waver to and from visibility uncontrollably especially when exposed to rapidly changing backgrounds, such as the clouds of a gas giant. One of the later camouflage systems employed on the Sahara-class heavy prowler involves a generated field of camouflage which surrounds the ship. These advances allowed prowlers to keep ahead of similar advancements in Covenant sensor technology.

More traditional Covenant-based active camouflages and newer emission-distortion grids made their way into prowler designs in the post-war era ships, though by 2558 only a select few Winter-class prowlers had been fitted with them. Active camouflage systems are limited in their usage, and can only keep the ship in stealth mode for a few minutes at a time—making their optimal usage a key consideration for planning.

Engine emissions are typically masked via the use of baffled fusion drives—a type of experimental and cutting edge