Tag: Japan

In a triumph of engineering, the salvaged Japanese Venus probe Akatsuki has beamed back to Earth its first science data.

After an unplanned five-year detour, Japan’s Venus probe, Akatsuki, has come back to life with a bang. On 4–8 April, the Japan Aerospace Exploration Agency (JAXA) presented the first scientific results from the spacecraft since it was rescued from an errant orbit around the Sun and rerouted to circle Venus, four months ago. These include a detailed shot of streaked, acidic clouds and a mysterious moving ‘bow’ shape in the planet’s atmosphere.

Despite the probe’s tumble around the Solar System, its instruments are working “almost perfectly”, Akatsuki project manager Masato Nakamura, a planetary scientist at JAXA’s Institute of Space and Astronautical Science in Sagamihara, Japan, announced at the Inter­national Venus Conference in Oxford, UK. And if another small manoeuvre in two years’ time is successful, he said, the spacecraft might avoid Venus’s solar-power-draining shadow, and so be able to orbit the planet for five years, rather than the two it was initially assigned.

The timing is also good, since Akatsuki is now the only probe circling Venus, and will be for a number of years, until someone else approves, builds, and launches a mission.

After a five year delay because its initial attempt to enter Venus orbit failed, the Japanese probe Akatsuki is finally about to begin science operations.

Its present orbit is less than ideal, passing 440,000km from the planet at its farthest point. That is roughly five times greater than initially planned and means the orbit time is now nine days. The change in orbit has affected the probe’s observation plan. Of its seven planned missions, Akatsuki will be able to complete only one: taking serial images of clouds. Unfortunately, the probe’s five cameras, each capturing images in different wavelengths, including infrared and ultraviolet, will not be able to provide the same resolution at this greater distance. Observing volcanic eruptions on the Venusian surface may also be difficult.

There is an upside to the situation, however. Takeshi Imamura, an associate professor at JAXA’s Institute of Space and Astronautical Science, says the longer orbital period means the probe will be able to collect longer continuous stretches of data.

Considering everything, it is magnificent that Akatsuki will be able to do any science at Venus at all.

Five years after the Japanese Venus probe Akatsuki’s main engines failed while trying to put it into orbit, the spacecraft today fired its attitude thrusters and was successfully inserted into orbit.

This is a singular achievement by the Japanese engineers running the mission. They improvised a plan using the thrusters, which were designed to adjust the spacecraft orientation, not its course, and were able to get Akatsuki in an solar orbit that brought it back to Venus.

A Japanese Venus research spacecraft, dubbed Akatsuki, has completed all its preliminary course corrections and is ready for a December 7 orbital insertion attempt, the second since the spacecraft’s main engine failed during the first attempt in 2010.

The space probe accomplished its last targeting maneuver Oct. 11 to aim for its Dec. 7 arrival at Venus, and all systems are go for the encounter, said Takeshi Imamura, Akatsuki’s project scientist at JAXA’s Institute of Space and Astronautical Science. Imamura said the Akatsuki spacecraft, named for the Japanese word for dawn, will zoom 541 kilometers, or 336 miles, above Venus for a 20-minute insertion burn using the probe’s secondary attitude control thrusters. Japanese ground controllers have programmed the probe to use the backup rocket jets after a faulty valve knocked out Akatsuki’s main engine during its first attempt to enter orbit around Venus in December 2010.

Four of the eight attitude control thrusters aboard Akatsuki will fire for 20 minutes and 33 seconds to slow the spacecraft down enough for Venus’ gravity to pull it into an egg-shaped orbit that skims above the planet’s cloud tops on the low end and ranges several hundred thousand miles in altitude at peak altitude. The reaction control thrusters, originally designed to help point the spacecraft, were not rated for such a hefty propulsive maneuver.

To make this second chance possible, they have spent the last five years improvising. First they dumped the fuel from the now-useless main engine to make the spacecraft lighter so that the attitude control thrusters could handle the maneuvers. Then they used those thrusters repeatedly to adjust the course to bring Akatsuki back to Venus after it zipped past in 2010.

If they succeed in getting it in a useful orbit on December 7, it will be real triumph for these Japanese engineers.

Five years after it failed to enter Venus orbit as planned, the Japanese probe Akatsuki is about to try again, in December.

The article provides an interesting and detailed explanation of what had gone wrong in 2010, and then describes the amazing things engineers have done to make this second attempt even possible. If they succeed it will be one of the most brilliant achievements in the history of space exploration.