TOKYO (AP) -- A Japanese probe reached Venus on Tuesday and prepared to enter orbit on a two-year mission that would mark a major milestone for Japan's space program and could shed light on the climate of Earth's mysterious neighbor.
The probe, called Akatsuki, which means "dawn," would be the first Japan has ever placed into orbit around another planet and comes after the country recently brought a probe back from a trip to an asteroid.
Other space programs, including the Americans' and the Europeans', have successfully launched missions to orbit other planets.
Scientists said they briefly lost contact with the probe early Tuesday. They encountered new communication problems later in the day and were not able to confirm if it was successful.
Agency spokesman Tsutomu Yoshioka said it would take several more hours than expected to determine the probe's status.
Japan has been overshadowed in recent years by the big strides of China, which has put astronauts in space twice since 2003 and was the third country to send a human into orbit after Russia and the United States,
However, Japan has long been one of the world's leading space-faring nations. It was the first Asian country to put a satellite in orbit around the Earth - in 1970 - and has developed a highly reliable booster rocket in its H-2 series.
Japan's space program has never attempted manned flight and instead operates on a shoestring budget that focuses primarily on small-scale scientific projects.
Akatsuki, which was launched May 20, is designed to monitor volcanic activity on Venus and provide data on its thick cloud cover and climate, including whether the planet has lightning. The probe is equipped with infrared cameras and other instruments to carry out its mission.
The 25-billion-yen ($300-million) project is supposed to maintain an elliptical orbit around Venus, ranging from passes 190 miles (300 kilometers) from the planet's surface to outer swings 50,000 miles (80,000 kilometers) away that will allow it to comprehensively monitor weather patterns.
One of the mysteries scientists are hoping to clear up is the intensity of surface winds on Venus that are believed to reach up to speeds of 220 miles per hour (360 kilometers per hour).
Japan's space agency, called JAXA, said the probe was to continue monitoring Venus from its orbit for two years.
Inserting the probe into orbit would be a big success for Japan, which previously failed in an effort to put probes around Mars. The Mars mission, called Nozomi, or "hope," and launched in 1998 experienced a series of technical glitches.
The program got a big morale boost earlier this year with the successful return to Earth in June of the Hayabusa probe.
Hayabusa successfully captured dust from an asteroid for the first time in history, bringing back microscopic samples from the Itokawa asteroid that could offer insight into the creation and makeup of the solar system.
It is only the fourth set of samples to be returned from space in history - including moon matter collected by the Apollo missions, comet material by Stardust, and solar matter from the Genesis mission.
The spacecraft's capsule landed successfully in the Australian Outback in June after a seven-year, 4-billion-mile (6-billion-kilometer) journey.
The Venus mission also follows Japan's first lunar probe, which completed a 19-month mission last year. The lunar project gathered data for a detailed map of the moon's surface and examined its mineral distribution.
NASA has launched several probes that have orbited other planets: Pioneer Venus in 1978, Mars Global Surveyor in 1998 and Messenger, which is expected to settle into orbit around Mercury in 2011. The European Space Agency's Mars Express successfully reached orbit in 2003, while its Venus Express completed the maneuver in 2006.