The YMF-X000A Dreadnought Gundam (aka Dreadnaught, X Astray) is a Mobile Suit introduced in the manga Mobile Suit Gundam SEED X Astray. Its main pilot is Prayer Reverie.

Based on technology stolen from the Earth Alliance, the Dreadnought was jointly developed by PLANT's three primary military design bureaus: Clarke, Asimov, and Heinlein. It was a testbed for ZAFT's newly developed Neutron Jammer Canceller, which allowed the use of nuclear power under Neutron Jammer interference, making it the first mobile suit to be powered by a nuclear engine. The Dreadnought's Neutron Jammer Canceller was installed in its head, unlike the later nuclear-powered mobile suits that were developed using its data. Therefore, while its head was a custom made, Gundam type head, its body reused many parts from the ZGMF-600 GuAIZ to shorten its development time. Additionally, several of its weapons were based on those used by the GuAIZ.

Due to its prototype nature, the Dreadnought's Neutron Jammer Canceller has a greater effective range than later units. Instead of being confined to the Dreadnought's nuclear engine, it also allowed nuclear reactions to occur nearby. Taking advantage of the nuclear engine's high output, the Dreadnought was equipped with the Phase Shift armor and the new DRAGOON System, both of which consume massive amount of power. In case the Neutron Jammer Canceller is missing or inoperable, the Dreadnought could still function using its internal battery, though it was unable to use the Phase Shift armor in this state.

The DRAGOON System (Disconnected Rapid Armament Group Overlook Operation Network System) is similar in concept to the Wired Gunbarrels equipped by the Alliance's TS-MA2mod.00 Moebius Zero, but its remote weaponry are controlled wirelessly via quantum communication, which is immune to the Neutron Jammers' disruptive effects. The power intensive nature of the DRAGOON System is attributed to the quantum communication. Like the Wired Gunbarrels, the DRAGOON System can only be operated by pilots who have a high level of spatial awareness. Initially, the Dreadnought's remote weaponry only consisted of two waisted-mounted XM1 "Pristis" Beam Reamers, it gained more remote weaponry when a large, X-shaped backpack armed with four DRAGOON units was later mounted onto the mobile suit.

The word 'Dreadnought' means a fearless person, and officially, it was selected as the name of this mobile suit to convey the wish that it would be a fearless machine that protects the PLANTs. However, at the development site, it was joked that the name refers to the mobile suit's pilot, who borne increased risk as the machine has a dangerous nuclear engine. Despite this joke, the Dreadnought is said to be safe as sufficient protection is built-in. With the X-shaped backpack, the Dreadnought is also called 'X Astray', but it is unrelated to the Astray series mobile suits. The 'X' is a reference to the shape of its backpack, while 'Astray' is derived from the fact that although the Dreadnought was meant to be a weapon for killing, its pilot, Prayer Reverie, wanted to use it for saving lives instead.