Japanese space probe set to orbit Venus on maiden voyage

English News cn: Japanese space probe set to orbit Venus on maiden voyage

Japanese space probe set to orbit Venus on maiden voyage

English.news.cn 2010-12-07 12:13:08 FeedbackPrintRSS

TOKYO, Dec. 7 (Xinhua) -- Japan's Akatsuki spacecraft on Tuesday morning fired its primary maneuvering engine for about 12 minutes to slow the probe enough for it to enter Venusian gravity and begin its orbit of the planet, Japan Aerospace Exploration Agency (JAXA) officials said.

Akatsuki, the 300 million U.S. dollar, 1,000-pound probe, has been speeding toward Venus since launching on May 20 from the Tanegashima Space Center, but JAXA officials said they will have to wait till this afternoon to confirm the craft's successful entrance into Venus' orbit.

The JAXA officials said the probe would have only one chance to enter orbit, because if it fails, it will pass over Venus.

Providing the probe successfully enters Venus' orbit, it will mark the first time in Japan's space exploration history that a space probe has been placed in orbit around a planet other than Earth.

Akatsuki (meaning "Dawn" in Japanese) will conduct several attitude control thruster burns in order to maneuver the craft so that its communications antenna points toward Earth so the probe can radio its status back to ground controllers.

Once the probe is successfully in orbit, it will adjust its position to eventually move into the targeted oval orbit circling the planet in 30 hours at altitudes of 550 to 80,000 km around Dec. 13.

The orbiter launched with Japan's Ikaros solar sail, which successfully unfurled an ultra-thin sail membrane last summer and demonstrated its viability as an alternative propulsion source.

Ikaros is also on a trajectory toward Venus, but it will sail past the planet later this month and continue circling the sun.

Akatsuki's five cameras will collect unparalleled data on the planet's atmosphere and runaway greenhouse effect for a two-year mission.

Each of the probe's cameras is designed to study a particular segment of the Venusian atmosphere, ranging from surface imagery to observations of the planet's sulfur cloud tops at an altitude of 60 miles.

Akatsuki is also equipped with short-wave infrared imagers to look for active volcanoes, search for lightning storms, chart the distribution of water vapor and carbon monoxide and map the surface of Venus.

JAXA said shedding light on meteorological phenomena in Venus will help understand why Venus and Earth, the two planets most similar in size and distances from the sun, have very different environments, with the atmosphere of Venus being made up of thick carbon dioxide, clouds of sulfuric acid and super-rotating jet stream winds of up to 225 mph. The study will also deepen understanding of Earth, the officials said.

"Although Venus is believed to have formed under similar conditions to Earth, it is a completely different world from our planet, with extremely high temperatures due to the greenhouse effect of carbon dioxide and a super-rotating atmosphere blanketed by thick clouds of sulfuric acid," said Takeshi Imamura, Akatsuki' s project scientist.

Venus formed much like Earth and probably enjoyed calmer times in its ancient past. But something went wrong long ago, leading a potentially once-temperate Venus on an evolutionary course much different than Earth, according to expert astronomers.

"Using Akatsuki to investigate the atmosphere of Venus and comparing it with that of Earth, we hope to learn more about the factors determining planetary environments," Imamura said. "From this viewpoint, we will be able to understand more about the reason why Earth is as it is now, and how it might change in the future."