The Japan Aerospace Exploration Agency said Tuesday it has partially restored communication with the space probe Akatsuki but will need more time to confirm whether it has successfully entered orbit around Venus because of trouble that occurred after it reversed its engine as a final step.
The Japanese space agency said that Akatsuki has presumably secured electricity by automatically switching to a mode in which it holds its solar battery panel toward the sun, enabling partial data communication to be restored by Tuesday night Japan time.
‘‘Hopefully we’ll confirm that Akatsuki is in the right orbit by around Wednesday noon,’’ Masato Nakamura, manager of the Venus orbiter project, said at a press conference late Tuesday.
JAXA said it has confirmed that Akatsuki’s antennas are functioning properly and thus can receive some data, despite the failure to put it in its normal position necessary to secure sufficient communication.
If Akatsuki succeeds in entering orbit, it would be the first time Japan has placed a space probe in orbit around a planet other than Earth, fulfilling a goal of the country’s space engineers after a failed attempt between 1998 and 2003 to place a probe into orbit around Mars.
The achievement was expected to come about 200 days after a rocket carrying Akatsuki blasted off on May 21, during which time the probe traveled 520 million km to approach Venus.
Earlier, JAXA officials breathed a sigh of relief with the news that Akatsuki had gotten out of communication trouble.
‘‘We were able to figure out the movements of its radio waves and that is a big step. There is still hope,’’ Seiichi Sakamoto, professor of the JAXA’s Institute of Space and Astronautical Science, said.
Shortly before 9 a.m. Tuesday Japan time, JAXA received data showing that Akatsuki had begun reversing the engine to slow down as scheduled when it was about 550 kilometers above Venus.
JAXA did not receive a solid amount of data from Akatsuki after it moved behind Venus. The agency was unable to receive enough data even though the probe should have already reemerged to the front side of Venus, according to JAXA officials.
Akatsuki failed to switch to a mid-performance or high-performance antenna, which is capable of sending a large quantity of data, as was planned, they said.
According to JAXA, Akatsuki must reverse its engine for 12 minutes in order to enter orbit, with the probe having only one chance to do so, as a failed attempt would see it pass over Venus.
‘‘Eleven years have passed since the start of the Akatsuki project. I’m at the biggest moment of my life as a researcher,’’ said Naomoto Iwagami, a University of Tokyo associate professor in charge of the management of one of the special cameras on board the probe, in the control room.
As it takes about three minutes and 30 seconds for a one-way transmission to reach Akatsuki, now located about 63 million km from Earth, the command to reverse the probe was programmed in advance.
Once the probe is successfully in orbit, it will adjust its position to eventually move into the targeted oval orbit circling the planet in 30 hours at altitudes of 550 to 80,000 km around Dec 13.
It will then observe the atmosphere of the planet for over two years using various instruments including some to measure near-infrared rays and ultraviolet rays.
JAXA said shedding light on meteorological phenomena in Venus will help in understanding why Venus and Earth, the two planets most similar in size and distances from the sun, have very different environments.
Akatsuki was developed at a cost of 25.2 billion yen for Japan’s first planetary exploration mission since an unsuccessful stint by the Mars probe Nozomi, which was launched in 1998. In 2003 JAXA gave up trying to put Nozomi into orbit around the planet after a series of technical glitches.
JAXA officials said they used lessons learned from Nozomi’s failure in the development of Akatsuki.
Source : Japan Today
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