Posted on by Nicholos Wethington

Akatsuki Update: Fuel Pressure Drop Likely Caused Insertion Failure

An image showing Venus from three of Akatsuki's different instruments, taken during a functions check of the probe. From left to right: the ultraviolet imager (UVI), 1 micron camera (IR1) and long wave infrared camera (LIR). Image Credit: ISAS

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While JAXA is still trying to get an exact handle on the problems that the Akatsuki probe sent to Venus encountered, there is a little bit of news leaking out. JAXA held a press conference last night, and the Yomiuri Shimbun newspaper has a brief recap of the conference. During some of the systems checks on the probe, it also took a few images of Venus, and many of the instruments on the probe appear to be working okay – it’s the engine that’s having the most problems.

Here’s what is known so far: Akatsuki’s engine did perform a burn to slow it down, but 152 seconds into the burn the fuel pressure dropped and the probe became unbalanced. Because the retrofiring of the rockets failed to slow down the probe enough for Venus to capture it, it was unable to enter into orbit around the planet, and then went into safe mode.

As to what caused the sudden drop in fuel, JAXA currently suspects that there is a damaged pipe or valve that reduced the flow of helium into the engine, but that is still speculative. As the engine burns propellant (Akatsuki uses a hydrazine/nitrogen tetroxide engine), helium flows into the tank to maintain the pressure. Something failed in the helium injection flow, and precipitated a drop in internal tank pressure, reducing the flow of propellant and causing the engines to stop burning.

The ceramic nozzle of the engine is also thought to have been damaged by the misfiring, which may make the task of trying to get the probe to Venus when the chance comes around again in six years a daunting one.

An image of Venus taken by Akatsuki's Ultraviolet imager (UVI) at the 365 nm wavelength, the color is artificial. Field of View: 12 deg x 12 deg Image Credit: ISAS

JAXA is planning on doing some tests on the ground to maybe come to a workaround of this problem. There seems to be plenty of fuel left, which is good news, but the damaged nozzle is not. Maybe they’ll call in some Hayabusa team members, and pull it through.

The Christian Science Monitor reported yesterday that there is some speculation that something may have struck the probe, though this most recent press conference from JAXA makes no mention of it.

Also, Emily Lakdawalla at The Planetary Society Blog reprinted some tweets translated from Japanese that summarize details from the press conference, as well as the Yomiuri Shimbun article.

Source: Yomiuri Shimbun, ISAS, the Planetary Society Blog,

Posted on by Nancy Atkinson

Akatsuki Fails to Enter Orbit of Venus

Artist’s impression of the Venus Climate Orbiter (aka. “Akatsuki”) by Akihiro Ikeshita. Image Credit: JAXA

JAXA announced that the Akatsuki spacecraft failed to enter orbit around Venus. The orbit insertion maneuver was performed, the space agency said in a statement, but “unfortunately, we have found that the orbiter was not injected into the planned orbit as a result of orbit estimation.” While extremely disappointing, perhaps not all is lost. If the spacecraft can be stabilized, there is a chance it could enter orbit in 6 years when it passes by Venus again.

At a press conference, project manager Masato Nakamura said (from translated reports) that the spacecraft is functioning but has put itself in a standby mode with its solar panels facing towards the Sun. It is also spinning slowly — about every 10 minutes — and radio contact is possible only for 40 seconds at a time. Engineers are using ground antennas in Japan as well as NASA’s Deep Space Network to send commands to stabilize the spacecraft and to determine its trajectory.

JAXA said they have set up an investigation team to study the cause of the failure, and will provide updates with the countermeasures and investigation results.

Japan had a similar situation occur with their Nozomi spacecraft at Mars in 2003, when they lost contact with the spacecraft just 5 days before orbit insertion around the Red Planet.

Akatsuki was launched from the Tanegashima Space Center on May 21, 2010.

Posted on by Nancy Atkinson

Akatsuki Encounters Problems at Venus

Artists concept of Japan’s Akatsuki spacecraft at Venus. Credit: JAXA

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Japan’s first Venus space probe encountered problems while attempting orbit insertion and went into safe mode. It took longer than expected (an hour and a half) to regain communications after a known 22 minute blackout with the Akatsuki spacecraft, and apparently controllers are still trying to ascertain the spacecraft’s orbit. From translated Twitter reports and a document posted on the JAXA website, it appears engineers confirmed ignition of the thruster before Akatsuki moved behind Venus, but had trouble pinpointing the spacecraft after the blackout should have ended. They have regained some radio communications.

“It is not known which path the probe is following at the moment,” a JAXA official Munetaka Ueno told reporters at the ground control late Tuesday, according to AFP. “We are making maximum effort to readjust the probe.”

From a document posted early this Tuesday morning on a special JAXA website for Akatsuki (using Google Translate):

“The communication situation analysis has been confirmed that the spacecraft into safe hold mode,” says a translated document. “It is conducted to ensure continued operation of the information obtained at an early state of the spacecraft and orbital …stable spin probe to capture the sun.”

We’ll post more news as it becomes available.

Posted on by Nancy Atkinson

Japan’s Akatsuki to Reach Venus Today

Artists concept of Japan’s Akatsuki spacecraft at Venus. Credit: JAXA

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Japan’s Akatsuki spacecraft will arrive at Venus later today, and will enter orbit around the planet. The box-shaped orbiter will make observations from an elliptical orbit, from a distance of between 300 and 80,000 kilometers (186 to 49,600 miles), looking for — among other things — signs of lightning and active volcanoes.

The Akatsuki probe (Japanese for “Dawn”) has been traveling for six months, and launched along with the IKAROS solar sail mission. The timing for the orbit insertion burn is Dec. 6 at about 6:50 p.m. EST (2350 GMT), which is early Tuesday morning Japan Standard Time.

You can see more information at this Japanese website, or Emily Lakdawalla at the Planetary Society at translated the timing of events in English.

There’s also an English-version website that is providing some updates.

Twitters can follow Akatsuki. (in Japanese — Google translate works well on the spacecraft’s Twitter homepage.)

This is Japan’s first mission to Venus. The Japanese Space Agency, JAXA, hopes the spacecraft will work for two years studying Venus’s clouds and weather in order to gain a better understanding of how the planet’s atmosphere evolves over time.

Posted on by Nancy Atkinson

Japan’s Venus Orbiter and Solar Sail Missions Launch Successfully

Japan’s first robotic mission to Venus and an experimental solar sail launched successfully from the Tanegashima Space Center in southern Japan. The Venus Climate Orbiter, or Akatsuki, the IKAROS solar sail and several smaller payloads launched aboard an H-IIA rocket at 6:58 local time May 21 (21:58 UTC May 20). The video shows a very smooth-looking launch, and 27 minutes later, JAXA confirmed the successful separation of Akatsuki. Then, about 15 minutes after that, the solar sail canister separated.
Continue reading “Japan’s Venus Orbiter and Solar Sail Missions Launch Successfully”

Posted on by Nancy Atkinson

Japan to Launch Venus Orbiter and Solar Sail Missions

IKAROS - solar sail from Japan. Image: JAXA
IKAROS - solar sail from Japan. Image: JAXA

Bad weather postponed a scheduled multi-mission launch of an H-IIA rocket from Japan early Tuesday, which includes the first Japanese probe to Venus and an experimental solar sail. The next launch attempt for the “Akatsuki” Venus Climate Orbiter and the solar sail called IKAROS will be Thursday, May 20, at 21:58 UTC (May 20 at 5:58 EDT) – which is May 21 at 6:58 in Japan. Akatsuki is Japan’s first mission to Venus, and it will work closely with the ESA’s Venus Express, already at Venus. Also called Planet C, the box-shaped orbiter should arrive at Venus in December and observe the planet from an elliptical orbit, from a distance of between 300 and 80,000 kilometers (186 to 49,600 miles), looking for — among other things — signs of lightning and active volcanoes.

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Another payload is the solar sail, or “space yacht” IKAROS (Interplanetary Kite-craft Accelerated by Radiation of the Sun). This 320kg, 1.8m-wide, disc-shaped spacecraft will deploy an ultra-thin, ultra-light, 14 meter sail that will propel the structure from the radiation pressure from sunlight hitting it.

“The purpose of IKAROS is to demonstrate the technology of the Solar Power Sail,” said Osamu Mori, project leader of IKAROS. “Simply put, the solar sail is a ‘space yacht.’ A yacht moves forward on water, pushed by wind captured in its sails. A solar sail is propelled by sunlight instead of wind, so it’s a dream spaceship – it doesn’t require an engine or fuel. Part of IKAROS’s sail is covered by a solar cell made of an ultra-thin film, which generates electricity from sunlight.”

So far, solar sails have only been tested, but never flown successfully. It is hoped IKAROS will be the world’s first solar-powered sail, and that the structure will sail towards Venus, following Akatsuki.

The experimental sail is thinner than a human hair, is also equipped with thin-film solar cells to generate electricity, creating what JAXA calls “a hybrid technology of electricity and pressure.”

To control the path of IKAROS, engineers will change the angle at which sunlight particles bounce off the sail.

Akatsuki and IKAROS on the launch pad Taken on May 17, 2010, about 24 hours before the planned launch of Akatsuki and IKAROS toward Venus. They are stacked aboard an H-IIA rocket. Credit: Mitsubishi Heavy Industries, Ltd.

If you are a member of The Planetary Society, your name will be heading to Venus on both Akatsuki and IKAROS. The Planetary Society, a long-time proponent of solar sail technology, and Japan’s space exploration center, JSPEC/JAXA, have an agreement to collaborate and cooperate on public outreach and on technical information and results from IKAROS, which will help TPS plan for its upcoming launch of its own solar sail vehicle, LightSail-1, which they hope to launch in early 2011.

Emily Lakdawalla at the Planetary Blog has more details about the two missions and TPS’s involvement.

The H-IIA will also carry four other small satellites, developed by Japanese universities and other institutions. They include:

The 2-pound Negai CubeSat, developed by Soka University of Japan. Negai will test an information processing system during a three-week mission.

The WASEDA-SAT2, developed by Waseda University. The 2.6-pound spacecraft will conduct technology experiments in orbit.

The 3.3-pound KSAT spacecraft developed by Kagoshima University will conduct Earth observation experiments.

The 46-pound UNITEC-1 satellite from the Japanese University Space Engineering Consortium will test computer technologies and broadcast radio waves from deep space for decoding by amateur radio operators.

The rocket will launch from Japan’s Tanegashima Space Center in southern Japan.

For more information on IKAROS, read this interview with the project leader, Osamu Mori