The Japan Aerospace Exploration Agency said it lost communication with the probe temporarily. When it reestablished contact, it learned that Akatsuki had not entered Venus' orbit as it was scheduled to do Tuesday.
"We are sorry that we could not live up to the expectation of the people in Japan," Masato Nakamura, the project team leader said at a news conference.
Akatsuki, whose name means "dawn," was supposed to observe Venus for two years, the agency said.
Launched six months ago, its aim is to gather data on a Venusian wind pattern called super-rotation.
The refrigerator-sized probe is also supposed to study the sulfuric acid that envelops the planet and look for lightning.
A near-infrared camera on the probe also can peer through the murky atmosphere to get a glimpse of the planet's surface.
The Snooper Report.
Join us as we Take Our Country Back.
Sic vis pacem para bellum