Japanese and Chinese mission managers said their separate lunar orbiters, now halfway through yearlong missions, have performed flawlessly and are likely to be extended.

In presentations here March 26 to a meeting of the International Astronautical Federation, managers of Japan's Kaguya and China's Chang'e-1 programs said both programs are meeting their science objectives and their goals as pathfinders for future lunar landers in the middle of the next decade.

Susumu Sasaki, Kaguya project scientist at the Japan Aerospace Exploration Agency, JAXA, said both the main satellite and two smaller spacecraft jettisoned in lunar orbit for data-relay and gravity-field measurements have performed without a hitch.

Launched in September aboard a Japanese H-2A rocket on a yearlong mission, Kaguya and the two companion satellites are almost certain to have their mission extended by six months, Sasaki said. "The debate now is over lunar surface, or to leave it at around 100 kilometers," he said.

The data-relay satellite, Okina, is in an orbit with an apogee of 2,400 kilometers and a perigee of 100 kilometers. The Ouna gravity-field measurement satellite is in a 100-kilometer circular orbit inclined at 90 degrees, taking it over the lunar poles, as is the case with Kaguya. Kaguya weighed about 3,000 kilograms at launch. The two companion satellites weigh 50 kilograms each.

The Kaguya satellite carries a radar sounder capable of taking images up to 5,000 meters below the lunar surface with a resolution of 100 meters. The Okina data-relay satellite is used to beam Kaguya results to ground stations when Kaguya's orbit takes it over the far side of the Moon relative to Earth.

The mission also includes two high-definition cameras that have returned crystal-clear pictures of the lunar surface.

Sasaki said that all Kaguya science data will be released publicly in late 2009 — one year after the nominal 12-month mission concludes — even if Kaguya operations continue into 2009.

Sasaki said the success of Kaguya has given fresh impetus to the idea of launching one or two lunar landers around 2015, but he stressed that no budget commitments have been made for this.

The Chinese National Space Administration is in a similar situation following the early success of its Chang'e-1 satellite, launched in October aboard a Chinese Long March 3A rocket.

The 2,350-kilogram Chang'e-1, orbiting between 200 kilometers and 225 kilometers above the Moon's surface, is intended to be the first step in a three-stage Chinese lunar-exploration program that would include two robotic landers in the middle of the next decade and a sample-return mission around 2020.

Hao Xifan, deputy director of the Chinese Lunar Exploration Program Center, said Chang'e-1's platform and instruments have functioned without a glitch so far. The satellite is designed to take 3-D imagery of the lunar surface and analyze the lunar surface's composition. Chang'e-1, based on China's proven DFH-3 communications satellite platform, also is designed to test deep-space operations.

The European Space Agency (ESA), which has cooperated with China on science missions in the past, gave China detailed positioning and frequency-transmission information on ESA's Smart-1 lunar orbiter to permit Chinese lunar-program managers to test their own satellite-tracking stations in preparation for the Chang'e-1 mission.

ESA's Estrack satellite-tracking network, with stations in Australia and South America as well as in Europe, has been used for Chang'e-1. ESA officials have opened negotiations with China on a long-term cooperative effort in lunar exploration.

Chinese government officials in recent weeks have said that the success of Chang'e-1 puts the nation on track for a lunar lander mission in 2013. Hao said 2013-2015 remains feasible, but that the funding for such a mission has not been confirmed.