A Japanese H-2A rocket blasted off from the Tanegashima Space Center in southern Japan on Friday carrying the country's first Venus probe and an experimental solar sail, the country's space agency said.
The liftoff was initially scheduled early Tuesday, but was postponed until 1:58 Moscow time Friday [21:58 GMT Tuesday] due to poor weather conditions.
Akatsuki (Dawn), the rocket's main payload, will approach Venus in six months and will move around the planet in an ellicliptical orbit for two years to study the Earth's "sister planet" from the distance of 80-300 km. It has a mass of 500 lbs and a life expectancy of 4.5 years.
"Akatsuki will employ infrared light to observe and elucidate the mysteries surrounding the atmosphere under the clouds and the conditions on the planet's surface," Japan Aerospace Exploration Agency (JAXA) said in a mission overview.
Though Venus is similar to Earth in size, gravity and bulk composition, it is covered with a dense layer of highly reflective sulfuric acid clouds, making it almost impossible to see the planet's surface in visible light. To that end, Akatsuki is equipped with an ultraviolet imager and a longwave infrared camera.
One of the mission's main objectives is gain insight into the so-called "super-rotation" of the Venus's upper atmospheric layers, which results in severe storms raging with the speed of about 300 kmph.
"This phenomenon remains the biggest mystery of Venus, as it cannot be explained meteorologically," JAXA says.
In addition, the probe is expected to confirm the presence of active volcanoes and thunder on the planet.
The second project, IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun), was already dubbed a "space yacht" as it is accelerated by solar radiation. Its 0.0075 mm-thin sail of polyimide resin uses solar radiation to get propulsion.
The IKAROS will have the same starting trajectory as Akatsuki, but upon reaching the Venus orbit it will continue a three-year journey to reach the other side of the Sun.
Along with solar radiation, IKAROS gets additional electricity from thin film solar cells on its membrane.
"If the ion-propulsion engines with high specific impulse are driven by such solar cells, it can become a "hybrid" engine that is combined with photon acceleration to realize fuel-effective and flexible missions," JAXA says.
TOKYO, May 21 (RIA Novosti)
