Sea of Tranquility Affair
Commonly cited as the start of the Third World War due to it being the first event in open hostilities between the Free Market Block and the Eurasian Soviet, the Sea of Tranquility affair began on October 1, 2037, with the destruction of Station Spokoystviye, the soviet lunar base, by FMB Saboteurs. In retaliation, together with press activity denouncing the attack by Washington, Beijing timed their declaration of war against the Free Market Block with the launch of Operation Suihou Fengbaou, a nuclear strike against the joint Canadian-American moon base, in the early hours of October 2, 2037, which lead to a strategic nuclear exchange by both parties known as the First Battle of the Arctic that was ultimately unsuccessful in causing much destruction on either side thanks to the Photon Curtain and the Lucas Constellation, respectively.
Free Market Block Motivations
Prior to the incident, tensions were and had been high between the Free Market Block and the Eurasian Soviet, traceable all the way back to hostility between their major member nations dating as far back as the Second World War. The 20th and 21st Centuries were influenced in large part by this tension, including the First Space Race ultimately culminating in the Colonization of the Moon after the Humanoid Robotics Renaissance. Both the FMB and Eurasian Soviet had placed claims on the lunar surface as national territory, and each denied claims by the other to the same territory, in contravention of Outer Space Treaty, which otherwise lacked an enforcement mechanism.
Even after Third World War declassifications in the latter half of the 21st century, no official record or records made public suggested that any element of the FMB space, military, or intelligence organizations had been ordered to carry out the attack. However, given the absence of evidence to the contrary, and the general agreeability of other information in the years leading up to the event, the general consensus among historians is that the FMB Central Intelligence Directorate planted saboteurs among space agency personnel with the objective of destroying the Station Spokoystviye installation during a spacewalk.
Project Clarity Conspiracy Theory
In October of 2062, Project Clarity operatives acting under anonymity released a large trove of mostly-harmless military records from the security and intelligence services of the former Eurasian Soviet on the dark web and public internet. Within a matter of days, data miners acting on that information had constructed an elaborate conspiracy theory that alleges the documents in question show that the intelligence service of the Eurasian Soviet had actually carried out the attack, placing a single saboteur amongst the expected crew of the station, who latter destroyed the facility and killed himself in the attack. While the theory has never been corroborated and the authenticity of the Project Clarity leak is disputed, proponents argue that this sequence of events would have been far easier to carry out than an attack by a rival space agency.
Nature of Attack
On September 30th, 2037, a team of four CASA Astronauts, members of the crew of Moonbase Tranquility, were observed by crew aboard Station Spokoystviye to have violated the permiter of the Eurasian lunar colony. While no recorded observations exist, the popular account of the incident has the four astronauts taking up a position within line of sight of the moonbase, armed with one or more speculated beam weapons in violation of the Outer Space Treaty. It is believed that the astronauts had stashed their equipment at this location prior to returning to their point of origin to resupply.
Logs recovered from the Station Spokoystviye central computer, corroborated against transmitted logs sent back to earth from the station in real time, indicate a series of events beginning with an explosion in or near the base's Life Sciences Module, responsible for atmospheric maintenance and other life support systems. Less than five minutes later, hull breaches were recorded in all seventeen base modules along with fires in no fewer than 7. Transmissions ceased 15 minutes later with what was presumed to be the failure-by-destruction of key components of the L-SCALA central computer, which subsequent investigation showed to have been significantly damaged by fire.
The incident left no survivors from Station Spokoystviye. Later investigative expeditions by the surviving Eurasian Soviet after the Third World War as well as factfinding missions from the Western Sphere Hegemony in the same time period revealed that the cause of death for all members of the crew was asphyxiation following loss of cabin pressure, and corroborated that the attack was executed using beam weapons.
Aftermath
On the day following the attack, the Eurasian Soviet initiated the first formal combat of the Third World War by commencing Operation Suihou Fengbaou, which involved using a nuclear weapon launched from mainland china to destroy the CASA Moonbase Tranquility, which was viewed as a proportionate response. However, the launch was, for obvious reasons, not coordinated with foreign powers. The resultant decision making in the wake of the launch of the missile resulted in the first unrestricted strategic nuclear weapons exchange, known as the First Battle of the Arctic. Fortunately, none of the missiles involved found their targets as the efficiency of the Soviet Photon Curtain and FMB Lucas Constellation was far higher than expected.
The legacy of the Sea of Tranquility affair, even deeper than the Third World War, could be said to be found in the Martian Crisis. While the Free Market Block had more or less lost their hold on the moon with Operation Suihou Fengbaou, the Soviets maintained their research bases on the far side of the moon, and ultimately wound up establishing a government in exile there after the war.