Orbital defense platform
Orbital defense platform (ODP), also known as an orbital weapon platform, is a general term for a wide variety of space stations employed by the UNSC. Stations falling into this classification include unmanned weapon satellites all the way to large stations with a capital grade Magnetic Accelerator Cannon built into it. Some classes of ODP have the hull classification symbol of OWP.
Orbital defense platforms are frequently placed in geosynchronous orbit and deployed in groups, or clusters, of two to five platforms. The well-equipped and large bridge of an ODP is suitable for directing large-scale engagements. Such was the case when Fleet Admiral Sir Terrence Hood directed UNSC forces from an ODP during the Battle of Earth. These platforms are capable of destroying even the largest of Covenant capital ships but are vulnerable to Covenant boarding craft which can avoid the heavy slugs and latch onto the stations. If they survive the point defense guns, it is up to the UNSC personnel within the stations to repel any boarders.
Internally, the stations are remarkably spacious, complete with high ceilings and a monorail system to move personnel and equipment. In addition to numerous small craft bays, there are two docks for larger ships, such as freighters, or even frigates. These docking bays could possibly be used to hold Longsword fighters used to protect the station from hostile spacecraft. The design incorporates many features against potential hostile boarding action, including security stations and small arms racks situated at strategic locations.
The primary and crucial armament is a Mk. V "Super" Magnetic Accelerator Cannon capable of causing near-fatal damage to even a shielded Covenant capital warship with a single slug. The slug can weigh up to 3,000 tons and is launched at 4% the speed of light,[note 1] ensuring the complete annihilation of the target. As with starship-mounted MACs, a platform's cannon is commonly controlled by an AI. Due to the immense power of the MAC, a large recoil dampening system is situated at the base of the cannon. The weapon is vulnerable to the detonation of nuclear weapons, as their superconductive coils could be burned out from their electromagnetic pulse.
Point defense guns
ODPs do not possess the power generation equipment necessary to fire their main armament. Instead, they receive power from ground-based generators. An effective strategy to neutralize the formidable ODPs would be to disable the generators via ground assault. This would disable the platform's weaponry without destroying it, allowing this valuable prize to be captured or destroyed outright. The Covenant used this strategy during their invasion of Reach, dropping troops to the planet's surface and destroying these generators. This paved the way for Covenant forces to completely overwhelm the UNSC forces in the space battle over Reach.
By August 2552, Reach was protected by twenty ODPs. At least one of these platforms was in place by May 2517; a number were online by 2527. During the Fall of Reach, the orbital defense platforms inflicted massive losses on the Covenant armada in the opening stages of the battle, as well as providing fire support for ground forces on Reach. Large numbers of UNSC forces were deployed to protect the orbital platforms' planetside power generators, but they ultimately fell against determined enemy assaults. The disabling of the defense platforms was a major factor on the battle's outcome.
The outbreak of the Human-Covenant War prompted a massive expansion of Earth's defenses. Even as late as the Battle of Reach preparations had not yet been completed; a series of new platforms above Earth were set to come online on September 14. By October 2552, some 300 ODPs were operational. Many of Earth's ODPs were named after points of interest that they roughly kept station over.
A portion of the 300 platforms first saw action at the early stages of the Battle of Earth. Athens Station and Malta Station were each destroyed by antimatter charges installed by Covenant boarding parties, while Cairo Station only narrowly avoided the same fate as the other platforms thanks to Master Chief's removal of the bomb on board. The ODPs were used throughout the drawn-out Battle of Earth after Truth's fleet arrived, but the Covenant might have already destroyed numerous stations when Truth himself arrived at Earth on the Forerunner Dreadnought in November.
During the Didact's attack on Earth in mid-2557, ODPs defended Earth from the Didact alongside the ships of the UNSC Home Fleet. However, the Didact's ship Mantle's Approach was too heavily shielded for even the ODPs Super MACs and as a result, the Master Chief had to destroy the ship from the inside with a HAVOK nuclear warhead.
Several orbital defense platforms held station above the Outer Colony of Meridian, owing to the world's critical importance as an industrial supplier of the UNSC; these stations were lost to the Covenant during the Battle of Meridian in 2551.
Stations of the line
Halo: Fleet Battles
UNSC MAC Platform
This element includes a single ODP.
List of appearances