Japanese scientists say a probe sent on a two-year mission to Venus has failed to enter orbit and may have flown passed the planet.
The probe, called Akatsuki, which means dawn, appears to have not fired its engines enough to inject it into the proper orbit after it passed near Venus. Japan's space agency, called JAXA, said it still had communication with the probe.
Akatsuki, launched May 20, was 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.
Officials said the probe lost communications shortly after firing its engines to place it in orbit. Communication was restored, but the probe put itself on safety mode and did not achieve the position it needed to reach orbit.
JAXA said it had not given up hope.
"Unfortunately, it did not attain an orbit," said JAXA's Hitoshi Soeno. "But it appears to be functioning and we may be able to try again when it passes by Venus six years from now."
Inserting the probe into orbit would have been 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 25 billion yen ($300 million) Akatsuki probe was 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.
The failure Wednesday was a big letdown for Japan's space program.
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.
Japanese scientists had been hopeful of success with the Venus probe after the country recently brought a probe back from a trip to an asteroid.
Russia, the United States and the Europeans have successfully explored other planets. The Russian space program has been sending missions to Venus since 1961 with more than 30 attempts. Its early missions were marred with many failures.
But in recent years, Japan has been overshadowed 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.
Japan's space program has never attempted manned flight and instead operates on a shoestring budget that focuses primarily on small-scale scientific projects.
The program got a big morale boost earlier this year with the successful return to Earth in June of the Hayabusa probe. The probe 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 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.
