spaceSpace and Physics

Five Years After Its First Attempt, The Japanese Akatsuki Spacecraft Has Entered Orbit Around Venus


Dr. Alfredo Carpineti

Senior Staff Writer & Space Correspondent

clockDec 7 2015, 12:40 UTC
4236 Five Years After Its First Attempt, The Japanese Akatsuki Spacecraft Has Entered Orbit Around Venus
Artist's impression of Akatsuki orbiting Venus. JAXA

The Japanese Akatsuki spacecraft is now successfully orbiting the planet Venus, exactly five years after its first attempt at doing so. When it reached the planet on December 7, 2010, a malfunction to the main engine sent the probe hurling into space away from Venus. 

In the last five years, the Japanese Aerospace Exploration Agency (JAXA) has been working on a way to salvage the probe, which launched on May 20, 2010. They fired the auxiliary reaction control system (RCS), used by spacecraft to better align themselves, to adjust the trajectory of the probe and slow down into orbit after several revolutions of the Sun. The solution was a success. 


“The past five years have been a tough period for us,” said team member Takeshi Imamura, Nature reports.

When the spacecraft entered the Venusian orbit, it fired the RCS for 20 minutes, which slowed down the probe enough to be captured by the gravitational field of Venus. The JAXA team and a team of scientists in Australia were ready to provide additional instructions to the probe to stabilize the orbit, but this second maneuver was not necessary and Akatsuki is now safely orbiting Venus – the first spacecraft to do so since ESA's long-serving Venus Express entered the planet's atmosphere and was destroyed at the start of 2015.

Akatsuki, which means Dawn in Japanese, missed its chance to orbit Venus last time due to a faulty valve that forced too much oxidizer into the combustion chamber, which led to the engine overheating. The engine then shut down three minutes earlier than planned. That might not seem a long time, but without the additional engine boost the probe didn't slow down in time and continued its path away from the planet. 


The probe is equipped with several instruments, in addition to three different infrared cameras to study different layers of the Venusian atmosphere as well as looking for potential active volcanos. An ultraviolet camera will study the distribution of gasses in the atmosphere while a Lightning and Airglow Camera will look, as the name indicates, for the potential presence of lightning. The probe is also equipped with an oscillator to perform some radio observations.

The instruments will take the most sophisticated pictures of the atmosphere of Venus yet, and they will hopefully clarify some of its mysteries. Apart from its curious composition and the presence of lighting, the Venusian atmosphere moves 60 times faster than the planet's rotation (on Earth, winds are about 10 to 20 percent of the rotational speed), for reasons that are not fully understood.

In a statement, JAXA has stated that it's in the process of establishing the orbit of the craft around Venus – it is currently around than 17,000 kilometers (10,500 miles) from the surface – and after those operations are completed it will be able to announce on Wednesday December 9 when observations of Venus can begin. 

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