Defense Ministry Begins Development of ‘Bodyguard’ Satellites to Prevent Attacks by Other Countries’ ‘Killer’ Satellites

The Yomiuri Shimbun

1:00 JST, September 11, 2025

The Defense Ministry has begun work to create a prototype of “bodyguard” satellites that can protect Japanese satellites from attacks by other countries’ “killer” satellites.

The prototype is planned to pave the way for the introduction of bodyguard satellites in the future.

As China and Russia are developing killer satellites, the ministry plans to launch a small prototype of the bodyguard satellite by the end of fiscal 2029 to strengthen defense preparedness in outer space.

Killer satellites approach target satellites and obstruct their moves with robot arms or neutralize them with electromagnetic rays or by other means.

The Self-Defense Forces operate a set of three communications satellites. If these satellites are damaged, it is possible that communication among SDF units will be disrupted.

Such a scenario could seriously affect Japan’s national security.

The ministry aims to equip bodyguard satellites with the capability to obstruct the course of killer satellites when they approach Japanese satellites to stop the former from getting close to the latter.

The prototype will be used to confirm whether bodyguard satellites will be able to be quickly mobilized without any problems regarding geostationary orbits about 36,000 kilometers above the Earth in order to protect Japanese satellites from physical attacks.

In outer space, in addition to killer satellites, there is debris that could collide with satellites, and the amount of debris has been on the rise partly due to experiments by China and Russia to destroy satellites.

There is a separate plan to launch in fiscal 2026 the first of Space Domain Awareness (SDA) satellites, which will be used to confirm whether other countries’ satellites or other objects in orbit could be a threat to Japan.

It will check whether the camera installed in the prototype satellite will be able to take photos of other satellites. In the future, it is expected that bodyguard satellites will supplement the SDF’s monitoring capabilities.

The ministry plans to develop the prototype satellite at a cost of about ¥7 billion in a three-year period until fiscal 2027 and launch it in fiscal 2029 at the earliest.

The ministry is requesting hundreds of millions of yen as a preparatory expense for a full-fledged introduction in its initial budget request for next fiscal year.

Regarding the strengthening of defense capabilities in outer space, the Space Domain Defense Guidelines, which the ministry formulated in July, stipulate that the ministry aims “to deepen consideration on the protection of satellites.”