Japan wants to scale down the size of its spy satellites to enhance their maneuverability and hopes to launch a small fourth-generation satellite by around fiscal 2010, government sources said Monday.

The nation apparently wants to improve its satellites' photo-taking capabilities to be better able to spy on North Korea's nuclear facilities.

The current spy satellites, which weigh about 2 tons, are too heavy to turn quickly enough to take photos in a short period of time. The first-generation satellites were launched in fiscal 2002.

The smaller satellite is expected to be around 1.2 tons.

The current satellites orbit Earth at a speed of 29,000 kph along a north-south axis and can take photos of North Korea once every two days for only several minutes.

The government plans to launch second-generation spy satellites in fiscal 2005 and 2006 whose intelligence-gathering capabilities are almost identical to those of the existing satellites.