A file photo of a Japanese H-IIA rocket built by Mitsubishi Heavy Industries atop its launch pad at Tanegashima Space Center in southern Japan in 2016. An H-IIA rocket launched Japan's Information Gathering Satellite Radar 5 mission on March 16 EDT (early March 17 local time at the launch site).

Japan launched a new spy satellite into orbit tonight (March 16) to help keep an eye on the nation's unpredictable, nuclear-armed neighbor, North Korea.

The Information Gathering Satellite (IGS) Radar 5 lifted off atop a Japanese H-IIA rocket from Tanegashima Space Center in southern Japan at 9:20 p.m. EDT (0120 GMT, and 10:20 a.m. local Japan time on March 17).

While the Japan Aerospace Exploration Agency did not provide a live webcast for the IGS Radar 5 launch, a video stream was available via the company Neconvideo Visual Solutions.

Japan started the IGS program in 1998, presumably in response to North Korean missile tests around that time that sent missiles close to, or flying over, Japan.

In the years since, North Korea has repeatedly threatened to annihilate Japan (and South Korea and the United States), and continued to develop its nuclear-weapon and missile programs. The IGS satellites keep tabs on such efforts, help the Japanese government respond to natural disasters and perform several other functions, experts believe.

The first IGS craft lifted off in 2003. IGS Radar 5 is the 15th one in the program to take flight, though not all have made it to orbit. Two were lost to a launch failure in November 2003.

Some of the IGS spacecraft use optical sensors to study the ground below, whereas others depend on radar instruments. As its name suggests, IGS Radar 5 falls into this latter category.

Little else is known about the newly launched satellite; Japan does not reveal many details about its IGS spacecraft. It's unclear, for example, what orbit IGS Radar 5 will inhabit, though some of the satellite's predecessors are known to circle the Earth at an altitude of about 300 miles (480 kilometers).

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