The U.S. government made clear Thursday that it makes no sense to compare the rocket launches of the two Koreas.

"You know our view that there is no basis for comparing the behavior of the ROK in space with the behavior of the DPRK," State Department spokeswoman Victoria Nuland said at a press briefing.

She was using the acronym of the formal names of the Koreas -- the Republic of Korea and the Democratic People's Republic of Korea.

Earlier in the day, South Korea succeeded in its third attempt to put a scientific satellite into orbit. South Korea has secured communication with the satellite at 3:27 a.m. (local time).

Nuland confirmed that South Korea's launch was successful, citing an assessment by U.S. officials who observed it.

South Korea has become the 11th nation to send a rocket out of the planet, although the realization of its long-time goal has been a bit overshadowed by a successful launch by North Korea over a month earlier.

The U.S., however, drew a clear line between the two in terms of the transparency of their programs.

"The DPRK (North Korea), obviously, is completely proscribed under binding U.N. Security Council resolutions from -- based on its ballistic missile activity -- from any kind of launching, whereas the ROK (South Korea) has developed its space launch program completely responsibly," she said.

Nuland did not address a question about concerns that Seoul's move may drive a regional arms race.

She instead said Pyongyang will be able to enjoy the same right in a legitimate way if it comes clean on its weapons of mass destruction ambitions.

"The North shouldn't see it as a threat because they, too, can enjoy the same transparency with regard to the program that the rest of us have, which is a far cry from the way the DPRK itself behaves," she said.

Nuland sidestepped a question about whether her department formally regards North Korea as a member of the elite "global space club."

"I don't know what the definition of that is, but you know how concerned we are about any launch and any activity that involves ballistic missile technology," she said.

Another department official later pointed out that there is no formal definition for such a space club.

"It's not a formal designation or organization. So, we don't have an official position on who would be a 'member,'" the official told Yonhap News Agency on background.

U.S. space authorities confirmed North Korea's rocket, Unha-3, released a payload satellite into orbit Dec. 12. But it remains unclear whether the satellite is viable.

Experts say the North's launch was partially successful and emphasize the concern is the possibility of using the technology to fire long-range missiles.

"What North Korea launched was a space-launch vehicle carrying a satellite," said David Wright, co-director and senior scientist for the global security program at the Union of Concerned Scientists. "U.S. radars have seen the satellite that it successfully put into orbit, although that satellite appears to be rotating while orbiting, so it is not able to communicate with the ground."

The upper stage was designed to carry a light-weight satellite and not a warhead, which would be much heavier, he added.

The prominent U.S. rocket scientist told Yonhap, "The concern is that the technology used in this launcher could also be used to make a long-range missile." (Yonhap News)