TOKYO — Japan’s Venus climate orbiter Akatsuki was launched May 21 aboard an H-2A rocket from the Tanegashima Space Center in Kyushu, the Japan Aerospace Exploration Agency (JAXA) said in a release.

The 500-kilogram satellite, which was built by NEC Toshiba Space Systems Co. Ltd. of Yokohama,  separated from the rocket 27 minutes after liftoff, followed shortly by deployment of a solar sail experiment called the Interplanetary Kite-craft Accelerated by Radiation Of the Sun (IKAROS), JAXA said.

Akatsuki is due to arrive at Venus in early December and enter a 300-kilometer-by-80,000-kilometer orbit, then embark on a projected two-year mission to monitor the meteorology of the planet using five cameras to capture 3-D images of the structure and movement in Venus’ blanket of clouds, search for lightning and scan the planet’s surface for active volcanoes.

IKAROS, a 14-meter square spin-stabilized solar sail that contains thin-film solar cells, is designed to unfurl slowly over six months and follow Akatsuki to Venus to demonstrate interplanetary travel.

Japan spent 14.6 billion yen ($161 million) building Akatsuki and 9.8 billion yen for the launch, JAXA spokesman Akinori Hashimoto told Space News in a May 21 e-mail. The IKAROS solar sail experiment cost $1.5 billion yen to build, he said.

Akatsuki originally was slated to lift off May 18 but the launch was scrubbed late in the countdown due to bad weather forming in the rocket’s flight path.

The Akatsuki launch marked the 11th consecutive successful flight of the H-2 rocket since a November 2003 launch mishap that resulted in the destruction  of two reconnaissance satellites. The Mitsubishi Heavy Industries-built rocket has had 16 successful launches in 17 attempts since entering service in 2001.

A graduate of the Columbia Graduate School of Journalism, where he won the Horgan Prize for Excellence in Science Writing, Paul Kallender-Umezu is co-author of “In Defense of Japan: From the Market to the Military in Space Policy” (Stanford University...