Japan has successfully launched another optical (picture taking) spy satellite. This one joins two other optical birds and one radar satellite. This most recent satellite launch cost $109 million. The satellite cost quite a bit more. In early 2007, Japan lost the use of one of its two radar satellites. The "No. 1 radar satellite", which went into orbit in March 2003, was supposed to last for five years. But the bird has been having electrical problems, and had to be written off.
Nearly three years ago, Japan launched its fourth spy satellite into orbit, using a Japanese made rocket. The third bird was launched a few months earlier. The first two were launched in 2003. The 2006 launch was the second of two optical reconnaissance satellites. The cameras on board can make out objects as small as one meter in diameter. The best U.S. spy satellites can make out much smaller objects, but for Japan's needs then, one meter was adequate. The latest optical satellite, however, is believed capable of making our objects less than a third of a meter in diameter.
The other two birds carried radar, providing all weather coverage. Technically, the satellites are in violation of a 1969 Japanese law, which mandated Japan to only use space for non-military purposes. To get around this, these birds are technically non-military, and are not controlled by the military.
Japan had long refrained from launching military satellites, but this changed when North Korea fired a ballistic missile over Japan in 1998. Japan promptly set out to get eight surveillance satellites in orbit by 2006, in order to keep an eye on North Korean nuclear weapons and ballistic missile efforts. Japan has long relied on commercial photo satellites, and whatever they could get from the Americans. But for high resolution shots, on demand, of North Korea, and electronic eavesdropping from space, they need their own spy satellites. It is believed that the Japanese spy satellites are also being used to watch military developments in China and Russia.
The Japanese program has cost about two billion dollars. The optical satellites weigh about a ton, while the radar ones weigh about a third more. The United States provided a lot of technical assistance on the design and construction of the satellites. Japan built its own rockets to launch them. Like most spy satellite users, Japan does not report on how effective they are. It is known that Japan could get more detailed photos from commercial satellites. But those are not controlled by the Japanese government.