TOKYO - Japan's first space probe bound for Venus was struggling on Tuesday to enter the planet's orbit, the space agency said.

The Planet-C Venus Climate Orbiter, a box-shaped golden satellite fitted with two paddle-shaped solar panels, blasted off from a space centre in southern Japan in May.

The probe, nicknamed "Akatsuki" or "Dawn", reversed its engine to slow down and enter the planet's gravitational field but lost contact with ground control longer than had been anticipated, the Japan Aerospace Exploration Agency (JAXA) said.

It was thought to be on an abnormal course and was able to communicate by using only one of its three antennae when the blackout ended.

"It is not known which path the probe is following at the moment," JAXA official Munetaka Ueno told reporters at the ground control late Tuesday. "We are making maximum effort to readjust the probe."

Venus is similar in size and age to Earth but has a far more hostile climate, with temperatures around 460 degrees Celsius and large amounts of carbon dioxide, the primary greenhouse gas on Earth.

Scientists believe an investigation of the climate of Venus will help them deepen their understanding of the formation of the Earth's environment and its future.

Fitted with five cameras, the probe will peer through the planet's thick layer of sulphuric acid clouds to monitor the meteorology of Venus, search for possible lightning, and scan its crust for active volcanoes.

Akatsuki will work closely with the European Space Agency's Venus Express.