Faulty Valve Caused Akatsuki Failure at Venus

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The Japanese space agency has deduced that a faulty engine valve was the reason the Akatsuki spacecraft did not go into orbit around Venus as planned on December 6, 2010. According to the Daily Yomiuri, a malfunctioning valve in the probe’s fuel pressure system caused the engine to function abnormally. The valve is a standard component in many previous space missions, JAXA said, and it was not modified at all for Akatsuki.

Earlier, JAXA reported that 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.

The JAXA investigation identified five possible causes of the mishap and all stemmed from the valve’s failure to open. JAXA also said they intend “to further investigate why the valve did not open, and how much damage was caused to Akatsuki’s thruster nozzle, by conducting tests that also will indicate whether the probe will be able to go into orbit around Venus when it comes near the planet six years from now.”

After Akatsuki’s launch in May, the functions of its main engine were tested in June. However, the engine was fired for too short a time to detect the problem with the valve, JAXA said.

The findings were presented to the Education, Culture, Sports, Science and Technology Ministry’s Space Activities Commission.

Source: Daily Yomiuri

No Asteroid Particles Found in Second Hayabusa Compartment, But More in First

Artist concept of the Hayabusa spacecraft, which visited asteroid Itokawa in 2005 and returned samples to Earth in 2010. Credit: JAXA

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No visible material from asteroid Itokawa was found inside the second compartment of a canister returned to Earth by the Hayabusa spacecraft. However, JAXA also announced that more micron-sized grains have been found in the first compartment, opened earlier this year. Reportedly, the first compartment has about 1,500 tiny particles, however some might be aluminum particles from the container itself. But about 20 grains were rocky or mineral-based. However, according to the Daily Yomiuri Online, no visible material was inside the second chamber, although further investigations of the second compartment will be done with a special microscope.

Hayabusa attempted to land on Itokawa twice. The cylindrical canister was divided into two chambers, and the second chamber was to contain material collected during the spacecraft’s first landing.
JAXA officials expect the second compartment to contain more microscopic particles from Itokawa since the first landing was longer than the second.

As far as the particles from the first chamber, several have been observed with an electron microscope, and according to UmannedSpaceflight.com, the “rocky” ones are 30 microns in size, with several larger ones are about 100 microns.

JAXA hopes to provide more insight on the nature of the grains by the end of the year.

Akatsuki Update: Fuel Pressure Drop Likely Caused Insertion Failure

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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,

Akatsuki Fails to Enter Orbit of Venus

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.

Akatsuki Encounters Problems at Venus

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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.

Japan’s Akatsuki to Reach Venus Today

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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.

Separation Camera Takes Full Images and ‘Movie’ of IKAROS Solar Sail

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Two small “separation cameras” were ejected from JAXA’s (Japan Aerospace Exploration Agency) IKAROS solar sail, which successfully took some amazing full images of the fully deployed sail. The cameras are quite small, cylindrical in shape about 6 cm in diameter and height. They were ejected from the sail using a spring, and then they looked back at IKAROS, and relayed the images wirelessly. The cameras are now floating off into space, having done their job of taking these images. Below, an animation, or movie made by combining several images.


An animation created from several pictures taken by the DCAM2 on IKAROS. The camera rotated as it was ejected from the solar sail, so it is rotating, not IKAROS. Credit: JAXA

From the JAXA press release:

We will measure and observe the power generation status of the thin film solar cells, accelerate the satellite by photon pressure, and verify the orbit control through that acceleration. Through these activities, we will ultimately aim at acquiring navigation technology through the solar sail.

So, now that we know the sail is fully deployed, next comes the big test of whether solar sailing will actually work. This is huge, to finally have the opportunity to test a solar sail in space.

Close-up of the middle of the IKAROS solar sail, taken by the DCAM2. Credit: JAXA

From the IKAROS blog, speaking as the cameras:

Unfortunately I only have the battery, and…working time is very short for about 15 minutes after I do my best work is a planets around the Sun, the world’s smallest man-made flying with IKAROS continue.

Translation: these tiny cameras only had about 15 minutes to do their job of taking pictures before becoming dead little satellites orbiting around the sun.

IKAROS was launched on May 21, 2010 from the Tanegashima Space Center in Japan.

We’ll keep you posted as JAXA begins testing the solar sail.

IKAROS graphic of how the sail deployed. Credit: JAXA

Hayabusa Sample Return Capsule Retrieved

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Scientists from Japan were given the go-ahead to retrieve the sample return capsule from the Hayabusa spacecraft, which is hoped to contain the first piece of asteroid ever brought to Earth, perhaps providing insight into the origins of asteroids – and our universe. The capsule was ejected three hours before reaching Earth, and the sample canister descended through Earth’s atmosphere, preceding the spacecraft which broke up in spectacular fashion (click here to see the video) over the Australian Outback. The capsule lay in the Woomera Prohibited Area until morning when Aboriginal elders deemed it had not landed in any indigenous sacred sites, giving the OK for the scientists to retrieve it.

The insulated and cushioned re-entry capsule, 40 cm in diameter and 25 cm deep has a mass of about 20 kg. The capsule had a convex nose covered with a 3 cm thick ablative heat shield to protect the samples from the high velocity (~13 km/s) re-entry.

Apparently, it landed right on target. The director of the Woomera test range, Doug Gerrie, said the probe had completed a textbook landing in the South Australian desert. “They landed it exactly where they nominated they would.

Hayabusa's heat shield was also recovered from the Australian outback. Credit: JAXA

The capsule will remain sealed until it arrives at the JAXA facility near Tokyo, and may remain unopened for weeks as it undergoes testing.

The mission launched in 2003, and endured a series of technical glitches over its five-billion-kilometer (three-billion-mile) journey to the asteroid Itokawa and back. A large solar flare in late 2003 “injured” the solar panels, providing less power to Hayabusa’s ion engines, delaying the rendezvous with the asteroid. Then, as the spacecraft approached Itokawa, Hayabusa lost the use of its Y-axis reaction wheel. While it flew near the asteroid and sent back data, scientists and engineers aren’t sure if the spacecraft was successful in obtaining samples, as while it appears Hayabusa landed briefly, it is not certain the “bullets” fired to stir up dust for the container to capture. The return to Earth was delayed by three years from more thruster and navigational failures, but the JAXA team nursed and coaxed the spacecraft back home to a spectacular return. There was concern that the parachute batteries may be been depleted due to the extra time it took to get back to Earth, but obviously they worked quite well.

Sources: JAXA, NASA, AFP

Japanese Solar Sail Deploys Successfully

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New images and data from the IKAROS solar sail show the thin solar film has deployed and expanded successfully and is now generating power. Since its launch on May 21, 2010, teams from the Japan Aerospace Exploration Agency (JAXA), have been painstakingly checking out all the systems on IKAROS before deploying the sail, and even the process of unfurling the sail had been a slow process. JAXA began to deploy the sail on June 3, analyzing each step before proceeding. Yesterday, JAXA released a photo of a partially deployed sail (below), but didn’t offer much information as far as the status. But they now have confirmed that the sail was successfully expanded and is generating power. IKAROS is now about 7.7 million km from Earth.

In the image above, the harness is an electrical connection between the membrane and the main body, and the tether is the mechanical connection between the membrane and the main body.

And now comes the big test of the solar sail: will it provide the ability to navigate the spacecraft?

“We will measure and observe the power generation status of the thin film solar cells, accelerate the satellite by photon pressure, and verify the orbit control through that acceleration,” JAXA said in a press release. “Through these activities, we will ultimately aim at acquiring navigation technology through the solar sail.”

The craft will head towards Venus, and the exciting part will be finding out how fast and accurate the solar sail can fly.

Partial deploy of IKAROS, the first stage. Credit: JAXA

From the IKAROS blog (translated from Japanese):

First, the spin rate and learned that he had first IKAROS have successfully deployed from the attitude data. Then, I was part of the downlink data captured with the camera image monitor confirmed that the sail has been deployed from the image. On June 10 has been expanded to clean the sail, “stretched states” get the picture, confirmed the successful deployment of the sail after deployment finished the second check.

Also check the power of solar cells was carried out together, we achieved minimum success!

Power will be realized with the world’s first solar powered sail development.

Graphic showing the sail in full deployment. Credit: JAXA

See the IKAROS webpage for more info and detailed graphics.

Sources: JAXA, IKAROS blog

Japan Shoots for Robotic Moon Base by 2020

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These ARE the droids we’ve been looking for. The Japanese space agency, JAXA, has plans to build a base on the Moon by 2020. Not for humans, but for robots, and built by robots, too. A panel authorized by Japan’s prime minister has drawn up preliminary plans of how humanoid and rover robots will begin surveying the moon by 2015, and then begin construction of a base near the south pole of the moon. The robots and the base will run on solar power, with total costs about $2.2 billion USD, according to the panel chaired by Waseda University President Katsuhiko Shirai.

Moon base robot. Credit: JAXA

Some of the planned droids weigh about 300 kg (660 pounds) and move on tank-like treads. Reportedly, they will be able to operate within a 100 km (60 mile) radius of the base. They’ll be equipped with solar panels, seismographs to investigate the moon’s inner structure, high-def cameras, and arms to gather rock samples, which will be returned to Earth via a sample return rocket.

The exact location for the base will be chosen from high-resolution images returned by Japan’s Kaguya orbiter, which has provided stunning images of the Moon’s surface.

Previously, JAXA had set a goal of constructing a manned lunar base starting in about 2030, and apparently, the robotic base would be a precursor. That plan calls for astronauts to visit the Moon by around 2020 which is about the same timetable as the Indian Space Research Organization (ISRO) is hoping to have a manned mission to the Moon. The China National Space Administration (CNSA) has said they would like to have a manned lunar mission in 2030. NASA? Not sure yet. The Constellation program to return to the Moon has seemingly been axed, but it’s not going down without a fight from members of Congress and others. But surely, even if NASA decides an asteroid or Mars is their destination of choice, they would have to start by practicing on the Moon.

Let’s all work together on this and perhaps returning to the Moon will actually happen.

Source: NODE via PopSci