Tokyo, Japan - Japan on Saturday became the fifth nation to achieve a soft lunar landing, but said its Moon Sniper spacecraft was running out of power due to a solar battery problem.

After a nail-biting 20-minute descent, space agency JAXA said its Smart Lander for Investigating Moon (SLIM) had touched down and communication had been established.

But without the solar cells functioning, JAXA official Hitoshi Kuninaka said the craft – dubbed the Moon Sniper for its precision technology – would only have power for "several hours."

SLIM is one of several new lunar missions launched by governments and private firms, 50 years after the first human Moon landing.

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Crash landings and communication failures are rife, with only four other countries having made it to the Moon: the United States, Russia, China, and most recently India.

As mission control prioritized gathering data while they could, Kuninaka suggested that the batteries might work again once the angle of the sun changed.

"It's possible that it is not facing in the originally planned direction," he told an early-hours news conference.

"If the descent was not successful, it would have crashed at a very high speed. If that were the case, all functionality of the probe would be lost."

"But data is being sent to Earth," he added.

Prime Minister Fumio Kishida called the landing "very welcome news" but said he was aware that more "detailed analysis" on the solar cells was needed.

NASA chief Bill Nelson tweeted his "congratulations [to Japan] on being the historic fifth country to land successfully on the Moon."

"We value our partnership in the cosmos and continued collaboration," he said.

JAXA hopes to analyze data acquired during the landing, which will help determine whether the craft achieved the aim of landing within 100 yards of its intended landing spot.

SLIM was aiming for a crater where the Moon's mantle, the usually deep inner layer beneath its crust, is believed to be exposed on the surface.

Two probes detached successfully, JAXA said – one with a transmitter and another designed to trundle around the lunar surface beaming images to Earth.

This shape-shifting mini-rover, slightly bigger than a tennis ball, was co-developed by the firm behind the Transformer toys.

While the accuracy of the touchdown needs to be verified, Harvard–Smithsonian Center for Astrophysics astronomer Jonathan McDowell said, "I think the mission is a big success."

He noted that several things could have caused the solar panel problem.

"A wire came loose, a wire was connected the wrong way, or the lander is upside down and can't see the sun for some reason," McDowell speculated.

The scientist added that "hopefully" JAXA had been able to download images from the landing, but said an experiment to study the composition of Moon rocks may be a lost cause.

Moon Sniper's landing comes on the heels of the failed mission of Astrobotic's Peregrine lunar lander on Friday.