This article or section should be merged with Cosmic Era technology

In the anime Gundam Seed, Phase Shift armor is a technology designed to protect mobile suits from physical attack. Phase Shift, or "PS" armor, consists of an energy field generated through superconducting conduits in the armored surface of a mobile suit. When PS armor powers up, a hissing sound can be heard and the grey surface of the mobile suit's armor is overlaid in color, which is apparently predetermined when the armor is designed and cannot be altered. Once powered up, the PS armor takes minimal energy to maintain unless it is being actively attacked. ZAFT commander Andrew Waltfeld, through his observations of the Strike Gundam, estimated that that particular mobile suit in standard use can take approximately 72 hits with the missiles used by his corps' mobile suit, the TMF/A-802 BuCUE, before draining enough power to force a shutdown of the PS armor. Against the 76.2mm machine gun carried by the ZGMF-1017 GINN, the Strike Gundam's endurance is effectively unlimited.

PS armor was developed by the Earth Alliance and Morgenroete, Inc., and first rolled out in Cosmic Era 71. It remains in use as of CE 73. The first mobile suits to be equipped with PS Armor are the so-called "Gundams", GAT-X102 Duel Gundam, GAT-X103 Buster Gundam, GAT-X105 Strike Gundam, GAT-X207 Blitz Gundam and GAT-X303 Aegis Gundam.

The inverse of the Phase Shift armor concept is the Universal Century's I-field generator, which defends against beam weaponry but has no effect against physical attack.

Limitations

Because PS armor draws energy off of a mobile suit, the suits so equipped must have a means of replenishing that energy, or risk power depletion. During the war, the existence of N-Jammers limited mobile suits and mobile armors to operation on an energy battery (some mobile suits were equipped with various turbine engines to extend their operating time, but almost none had truly unlimited operational ability).

PS Armor grants near-invulnerability to projectiles, but it has virtually no effect on beam weapons, so most PS armored mobile suits carry a shield with an ablative anti-beam coating for defense against beams.

Nuclear power could give a PS armored mobile suit theoretically unlimited operating time, however during the Bloody Valentine War the widespread use of N-Jammers made this nearly impossible and afterward, the Treaty of Junius outlawed nuclear-powered mobile suits. Only five nuclear-powered mobile suits were made in any event, the ZGMF-X09A Justice Gundam, ZGMF-X10A Freedom Gundam, ZGMF-X11A Regenerate Gundam, YMF-X000A Dreadnought Gundam and ZGMF-X13A Providence Gundam. Each of these units got around the N-Jammer problem by incorporating an N-Jammer Canceller in their design, negating the effects of the N-Jammers in the field.

Development

During the war, OMNI Enforcer experimented with ways to extend the usefulness of PS Armor, leading to the development of Trans Phase armor (TP), which improved on PS Armor by only activating at the point of impact. However, this left TP armored mobile suits vulnerable to heavy attack from multiple vectors (a sufficiently powerful weapon could also overpower the TP armor), and at the end of the war, TP armor was apparently abandoned, along with the "living CPU" pilots of the three TP armored Gundams, GAT-X131 Calamity Gundam, GAT-X252 Forbidden Gundam and GAT-X370 Raider Gundam.

ZAFT continues to develop Phase Shift armor after the war (the Earth Alliance seems to have abandoned it for more conventional laminated armor), culminating in the development of Variable Phase Shift (VPS) Armor on the ZGMF-X56S Impulse Gundam, which alters the strength, and by extension the power consumption, to fit the suit's different configurations.