By Lyu Yaodong and Du Shaoshu
In the Space Domain Defense Guidelines released by Japan's Ministry of Defense in 2025, space is explicitly designated as an independent operational domain. The document proposes building a low-Earth-orbit military reconnaissance "satellite constellation" network, attempting to use the network to monitor the movements of ships and military forces around Japan while also providing targeting information support for long-range missiles, thereby constructing a so-called "standoff defense capability."
In April this year, Japan's low-orbit military reconnaissance satellite network, the "satellite constellation," officially entered operation. A Japanese parliamentary vice-minister of defense stated that the move is intended to ensure the effectiveness of long-range missiles as a means of "counterstrike capability". These developments indicate that Japan is breaking away from the "exclusively defense-oriented" principle and pushing for a comprehensive expansion of its military space capabilities.
Following the activation of this satellite network, Japan has acquired an initial capability to provide space-based reconnaissance and targeting support for long-range missiles. Japan's move is by no means an act of "self-defense." Rather, it is equipping long-range missiles with a "sky eye", and its military intent has already extended far beyond the scope of homeland defense.
The "satellite constellation" project is merely a phased step in Japan's push to militarize space. Guided by programmatic documents such as the Basic Plan on Space Policy and the Space Domain Defense Guidelines, Japan is advancing the development of its military space capabilities, and its ambition to become a military power has become increasingly evident. A document recently released by Japan's Ministry of Defense on strengthening space capability development proposes expanding the space operations command, increasing the defense budget, and deploying space situational awareness infrastructure. This demonstrates that Japan is continuously extending its so-called "enemy base strike capability" into the space domain in an attempt to seize the commanding heights of future military competition.
It must be pointed out that the pacifist Constitution and the "exclusively defense-oriented" principle constituted the political and legal foundation for Japan's return to the international community after WWII. Today, however, Japan is advancing military expansion under the guise of so-called "defense and self-protection" invoking concepts such as "space reconnaissance," "counterstrike capability," and "threat response," which fundamentally undermines the foundations of the postwar system and openly challenges the postwar international order. These moves serve as further evidence of Japan's substantive shift in military strategy from homeland defense toward long-range offensive capabilities.
The lessons of history are still fresh. Before WWII, Japan launched wars of aggression in the name of "self-defense," and during the war, it used large-scale intelligence-gathering operations to serve its military expansion, bringing immense disasters to neighboring Asian countries. The scars of history have not yet healed, yet Japan is now extending its intelligence-gathering reach into outer space.
No matter under what name or banner Japan acts, its push for the militarization of space and its hollowing out of the pacifist Constitution will pose a serious threat to regional peace and stability. Japan should deeply reflect on its history of aggression, face squarely the concerns of the international community, and abide by the "exclusively defense-oriented" principle, rather than intensifying regional tensions and confrontation through neo-militarism.
(The authors are from the University of Chinese Academy of Social Sciences.)