Tag Archives: Akatsuki

Two of five cameras on Japan’s Venus orbiter Akatsuki shut down

Japan has been forced to shut down operation on two of the five cameras on its Venus orbiter Akatsuki.

They think the problem has been caused by the additional five years required to get into Venus orbit when its main engine failed to fire during the first orbital attempt in 2010. During those five years the spacecraft was exposed to more radiation that expected, possibly damaging its equipment.

Akatsuki discovers a giant wave in Venus’ upper atmosphere

The Japanese Venus probe Akatsuki has discovered a giant persistent wave in the planet’s upper atmosphere that almost spans its entire face.

This week, researchers from Japan Aerospace Exploration Agency (JAXA) published infrared and ultraviolet images of Venus, taken by their Akatsuki orbiter between December 7 and 11, 2015, in Nature Geoscience. Akatsuki’s pictures reveal a curved region roughly 6000 miles long (Venus’ entire diameter is just around 7,500 miles) with a higher temperature than the surrounding atmosphere. How did the curved “smile” fight those high winds to remain in place for all four days of observation?

The answer may lie in a phenomenon very familiar to Earthlings. Gravity waves, not to be confused with gravitational waves, form when gravity pushes and pulls at the seam between two different materials. Waves on the ocean are perhaps the most obvious example—they exist where the sea meets the sky. But gravity waves also show up in the air, where wind flows over mountains to form waves that undulate upward through different layers of the atmosphere.

The mystery here is that scientists do not have a mountain chain that could have caused this giant Venusian wave. Moreover, it was there in 2015 but they haven’t seen it since.

Japan’s troubled space agency

Link here. The article describes how JAXA has pulled some remarkable successes out of the jaws of failure, but in describing these stories it made me realize how many of these failures have occurred, far more than one should expect. Just consider:

  • Nozomi failed to enter Mars orbit when its main engine did not fire as planned. The mission was a total loss.
  • Akatsuki failed to enter Venus orbit when its main engine did not fire as planned. The mission has been partly saved by the use of the spacecraft’s attitude thrusters to put it into Venus orbit five years late.
  • Hayabusa-1 had enormous problems, and was barely able to return to Earth with barely any asteroid samples, as had been the plan.

This list is essentially Japan’s entire interplanetary program since 2000, all of which failed in some significant way. The recovery of Akatsuki and Hayabusa-1 were hailed as great achievements, but in retrospect they both indicated a serious quality control problem in Japan’s space program. The loss of their most recent science X-ray telescope, Hitomi, when a software error caused the spacecraft to breakup in orbit only one month after launch, illustrated this again.

Japanese Venus probe sends back first science data

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.

Akatsuki to finally begin studying Venus

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.

Akatsuki’s Venus orbit confirmed

Venus in ultraviolet by Akatsuiki

Japanese engineers have confirmed that Akatsuki has entered orbit around Venus and can now begin science observations.

The image on the right was taken by the spacecraft’s ultraviolet camera, and clearly shows the as-yet unidentified dark material in Venus’s upper atmosphere. These dark streaks have been seen since the first Venus fly-by in the 1960s, but no observations have been able to determine what the material is that shows up as dark in ultraviolet light.

This success is a triumph for the engineers that operate Akatsuki. Kudos to them!

Success at last for Akatsuki

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.

Japan’s Venus probe zeros in on Dec 7 arrival

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.

Venus probe about to rise from the dead

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.

Five years later a second attempt to put a Japanese spacecraft into Venus orbit

If at first: After failing to place its Akatsuki spacecraft into orbit around Venus in 2010 because of a cracked engine nozzle, Japan has announced its plans for a new attempt later this year.

The attempt will be made on December 7. If successful, the spacecraft will begin studying Venus’s climate and atmosphere only a short time after the end of Europe’s very success Venus Express mission.

Akatsuki’s engine too damaged to put the probe into Venus orbit in 2015

The engine of Japan’s troubled Venus probe, Akatsuki, has been found too damaged to put the probe into Venus orbit.

JAXA conducted a test ignition of the probe’s main engine on Wednesday to prepare for another attempt to send it into orbit in 2015. But the thrust produced was only one-eighth the amount anticipated, the space agency said. The damage the engine suffered last December when JAXA ignited it in the initial attempt to send the probe into orbit around Venus appears to be more serious than thought, JAXA said.