A spacecraft built and flown by Texas-based company Intuitive Machines landed near the south pole of the moon on Thursday, the first US touchdown on the lunar surface in more than half a century and the first ever achieved by the private sector.

The uncrewed six-legged robot lander, dubbed Odysseus, touched down at about 6.23pm EST (7.23am HKT), the company and Nasa commentators said in a joint webcast of the landing from Intuitive Machines' mission operations centre in Houston.

The landing capped a nail-biting final approach and descent in which a problem surfaced with the spacecraft's autonomous navigation system that required engineers on the ground to employ an untested workaround at the 11th hour.

It also took some time after an anticipated radio blackout to re-establish communications with the spacecraft and determine its fate some 384,000km from Earth.

When contact was finally renewed, the signal was faint, confirming that the lander had touched down but leaving mission control immediately uncertain as to the precise condition and position of the vehicle, according to the webcast.

"Our equipment is on the surface of the moon, and we are transmitting, so congratulations IM team," Intuitive Machines mission director Tim Crain was heard telling the operations centre. "We'll see what more we can get from that."

Nasa Administrator Bill Nelson immediately hailed the feat as a "triumph", saying, "Odysseus has taken the moon."

As planned, the spacecraft was believed to have come to rest at a crater named Malapert A near the moon's south pole, according to the webcast. The spacecraft was not designed to provide live video of the landing, which came one day after the spacecraft reached lunar orbit and a week after its launch from Florida.

Thursday's landing represented the first controlled descent to the lunar surface by a US spacecraft since Apollo 17 in 1972, when Nasa's last crewed moon mission landed there with astronauts Gene Cernan and Harrison Schmitt.

To date, spacecraft from just four other countries have landed on the moon – China, the former Soviet Union, India and, mostly recently, just last month, Japan. The United States is the only one ever to have sent humans to the lunar surface.

The IM-1 mission was sent on its way to the moon last Thursday atop a Falcon 9 rocket launched by Elon Musk's company SpaceX from Nasa's Kennedy Space Center in Cape Canaveral, Florida. (Reuters)