South Korea says a satellite launched on Wednesday has made contact with a ground station and is sending data.
The launch was South Korea's first successful attempt to put a satellite into orbit using its own rocket.
The satellite, which collects climate data, made contact at 3.27am on Thursday.
President Lee Myung-bak said it was a "first step towards opening an era of space science in earnest".
"We should make this an opportunity to elevate national power by a notch," he said.
The rocket was launched from the NARO Space Center at 4pm on Wednesday. The BBC reports it had been delayed twice due to technical reasons.
The rocket was built in partnership with Russia. Two previous launches in 2009 and 2010 failed.
South Korea now plans to develop a fully home-made three-stage rocket.
North Korea successfully put its own satellite in orbit in December.