The Defense Ministry is thinking of developing an early warning satellite that can detect ballistic missiles in their boost phase to increase the effectiveness of the missile shield it is building, the ministry's recently released policy on development and use of space says.
A man-made orbiter would be the first step in Japan developing a satellite-based missile detection system of its own. Japan currently relies on the United States for information on ballistic missile launches, including those undertaken by North Korea.
The content of the ministry's basic space policy, released Friday, is expected to be included in the basic space development program due to be finalized in May by the Strategic Headquarters for Space Development.
The early warning satellite would be designed to use infrared sensors to detect heat released by a ballistic missile in its boost phase, giving Tokyo more time to respond.
But the project would likely face many hurdles, ranging from technical problems and huge costs to political risks, such as upsetting the United States, Japan's closest ally.
Developing such a satellite at a time when the Defense Ministry is facing severe budgetary constraints "could have an impact on the procurement of other pieces of equipment," a ministry official said.
In the basic policy, the Defense Ministry stressed that the early warning satellite could also perform other duties, including monitoring wild fires, volcanic activity and other natural disasters.