SEOUL, March 7 (Reuters) - North Korea appears preparing to launch a reconnaissance satellite, a move that may prove as controversial as the nuclear-armed country's weapons tests because they use the same banned ballistic missile technology, experts say.

North Korea conducted a record number of missile launches in January, and has suggested it could resume testing of nuclear weapons or its longest-range intercontinental ballistic missiles (ICBMs) for the first time since 2017.

After a test of satellite-related systems during a missile launch on Sunday - the second such test in a week - some experts think it is just a matter of time before North Korea attempts to put a satellite in orbit.

Here’s what we know about North Korea's race for space, and why it's so controversial:

History of launches

Since 1998 North Korea has launched five satellites, of which two appeared to have been successfully placed in orbit, including its last in 2016.

International observers said the satellite appeared to be under control, but there was lingering debate over whether it had sent any transmissions.

Experts at the time of the 2016 launch said that North Korea had used a three-stage rocket booster like the Unha-3 of previous launches, but that a new launch pad was clearly built for a larger rocket.

A senior official at North Korea’s space agency said after the launch that it planned to put more advanced satellites into orbit by 2020 and eventually “plant the flag of (North Korea) on the moon”. The country has not launched any more satellites since then, however.

During a party congress in January 2021, leader Kim Jong Un revealed a wish list that included developing military reconnaissance satellites.

Dual-use technology

The United States and its allies called North Korea’s latest tests of satellite systems clear violations of United Nations Security Council resolutions, which prohibit any development of technology applicable to North Korea's ballistic missile programmes.

North Korea has said its space programme and defence activities are its sovereign right.

At the time of the 2016 space launch, North Korea had yet to fire an ICBM. The satellite launch was condemned by governments in the United States and South Korea as a disguised test of ballistic missile technology capable of striking the continental United States.

“The obvious concern is that North Korea is testing ballistic missiles and only pretending to care about satellites,” the US-based monitoring program 38 North said in a report at the time.

The report said the Unha-3 system would be ungainly to use as a weapon because it required a fixed launching site and a long period for preparation, and predicted that North Korea would not develop an operational road-mobile ICBM until some time after 2020.

North Korea launched its first road-mobile ICBM the next year, and later test fired several more.

North Korea has not test fired an ICBM since 2017, but now officials in Washington and Seoul fear a new satellite launch could help the country further improve its ballistic missiles.

"In the future, if North Korea launches intercontinental ballistic missiles under the pretext of launching a satellite, it will face stronger pressure from the international community," Yoon Suk-yeol, the main conservative candidate in Wednesday's presidential election in South Korea, said in a statement after the latest launch.