TOKYO — The government is considering introducing space situational awareness (SSA) satellites to protect Japanese satellites from collisions with space debris and interference by satellites operated by other nations, The Yomiuri Shimbun has learned.
According to several government sources, launch of the SSA satellites, which are capable of monitoring an area in space, is being planned for a period from fiscal 2024 to fiscal 2028.
The government is making arrangements to have the National Defense Program Guidelines, the basic framework for the nation’s defense policy that will be revised at the end of this year, mention that “the entire government will be involved in efforts to significantly strengthen space situational awareness capabilities.”
SSA satellites monitor the movement of suspicious satellites, as well as space debris circling Earth at high speed — fragments of rockets, satellites that no longer operate, and other objects. If the SSA satellite recognizes a Japanese satellite is in danger, it will notify operators on the ground who can instruct the satellite to change its orbit and avoid a collision.
The government estimates each SSA satellite will cost about ¥15 billion, with each rocket launch costing from ¥5 billion to ¥10 billion, according to the sources.
The government began to consider introducing SSA satellites due to the growing threat posed to Japanese satellites by rapidly increasing pieces of space debris and the development of “killer satellites” (see below) by the Chinese and Russian militaries. Satellites play important roles for citizens in fields including security, observation, telecommunications and positioning systems.
If a communications satellite used by the Self-Defense Forces was damaged, command and control of units on the ground could be thrown into confusion. If an information-gathering satellite suffered damage, the nation’s surveillance capabilities would be impaired.
The government is currently developing a ground-based satellite-monitoring system that involves powerful radar and optical telescopes. This system is scheduled to start operating from fiscal 2023. However, some analysts have pointed out this system will struggle to maintain its monitoring capabilities during bad weather. By contrast, an SSA satellite has the advantage of being able to monitor a satellite at close range without being affected by the weather, enabling it to accurately gauge the presence of space debris and suspicious satellites.
The U.S. military already operates several SSA satellites. The government plans to further consider introducing such satellites while working closely with the U.S. government.
Senior officials in charge of this issue at the Defense Ministry; the Self-Defense Forces; the Education, Culture, Sports, Science and Technology Ministry; and other entities are planning to participate in multinational war games involving SSA satellites scheduled to be held in the United States this autumn, the sources said.
■Killer satellite
A military satellite that attacks another nation’s satellite in space. A killer satellite cripples a targeted satellite by methods including approaching the target and capturing it with a robotic arm. China aims to deploy such a satellite and in 2010 conducted an experiment in which two satellites were brought close together.