Hayabusa is an ambitious project. Its goal was to use ion engines and an Earth swing-by to take the craft to a rendezvous with an asteroid called Itokawa. The ion engines would fire continuously for nearly two years.

Once it had arrived at the asteroid it would “station keep”. It would not actually enter orbit around the asteroid but would maintain a steady distance from it whilst making observations. The “gate position” would be about 20 km from the target. Later the spacecraft would approach to a closer position called the “home position”.

It was planned that Hayabusa would release a tiny vehicle called the MIcro/Nano Experimental Robot Vehicle for Asteroid (MINERVA). MINERVA was to hop across the surface of asteroid and relay photographs to Hayabusa.

The main goal of the Hayabusa mission was to collect small samples of the asteroids surface and return them to the Earth. It was to do this by dropping target markers onto the asteroid and then making a brief touch down on the surface.

With the samples safely collected, and after a stay of about three months Hayabusa would restart its engine for the 4 year journey home. The samples would be returned to Earth in a capsule and would land in Woomera in Australia.

Hayabusa was launched on 9^th May 2003. After making a successful Earth fly-by on 19^th May 2004, the spacecraft arrived at Itokawa and achieved the “gate position” on 10^th September 2005.

However things did not go as planned. After a period of surveying the surface of Itokawa the MINERVA probe was lost when it was launched in the wrong direction causing it to miss Itokawa.

Hayabusa successfully touched down on the asteroid but it remains unclear if it managed to take any samples of material. When it was time to return home a major problem struck. A thruster problem caused the spacecraft to go into a "safe mode" and communications were lost. The Japanese controllers had a long fight to regain communication and control of the spacecraft not finally acieving this for a full two months. When they suceeded they found they had a crippled spacecraft. The spacecraft had suffered a major fuel leak and electrical problems including the loss of a battery.

More than a year after Hayabusa was so nearly lost JAXA are ready to begin to bring the spacecraft home. If all goes well the samples of asteroid Itokawa should return to Earth in June 2010.

April 4, 2007 Updated
Hayabusa to start return trip to Earth in mid April



The asteroid explorer "Hayabusa" which landed on the asteroid "Itokawa" November 2005, delivered its probe container for acquired samples to the re-entry capsule, stored it in the capsule, then tightly shut the lid (with latches and seals.)
Since February, JAXA tried a new attitude control method to operate the ion engine, and engine running trials in phases have been underway since late March.
It is scheduled to start fully fledged engine operations in mid April to return to Earth.
The operation of the Hayabusa is still undergoing difficulties, but JAXA will do its utmost to make the explorer return home in June 2010.

Source: JAXA - Missions - Hayabusa

The Japanese Space Exploration Agency (JAXA) press release is reproduced below:

Public release of the Hayabusa data archives

April 24, 2007 (JST)

Japan Aerospace Exploration Agency (JAXA)

The Hayabusa spacecraft, which was launched in May 2003, arrived at Asteroid Itokawa in September 2005, and it made observations of Itokawa and tried touch down in about three months.
Hayabusa has four scientific instruments, that is Multi-Spectral Telescopic Imager (AMICA), Laser Altimeter (LIDAR), Near-Infrared Spectrometer (NIRS), and X-ray Fluorescence Spectrometer (XRS). The data obtained by these instruments were firstly analyzed by Hayabusa Science Team and some of the results have been published as scientific papers. At the same time, the science team was preparing to open them to the public and this work has almost been done. Therefore the science team release the data archives to public from April 24, 2007. All the scientific data that Hayabusa obtained are open to the public.

The Hayabusa data archives can be accessed from the following web site:

http://hayabusa.sci.isas.jaxa.jp/

The data in the archives are mainly for scientific use. The web site is written in English for the access of researchers in all over the world. Following data can be obtained:

• AMICA: More than 1600 images taken by using wide-band filters of visual, near-ultraviolet, and near-infrared. The image of whole Itokawa and close-up view of the surface of Itokawa as well as the earth and the moon at the earth swinby.
• NIRS: About 120,000 spectral data in the near infrared. Mainly the spectra of the reflected sun light from the surface of Itokawa, but also the spectra of the earth, the moon, Mars, Jupiter, and Saturn.
• LIDAR: The data of distance from Hayabusa to the surface of Itokawa obtained by using LASER light. About 1.7 million points data are available.
• XRS: about 15,000 spectral data in X-ray. The fluorescence X-ray emitted from the surface of Itokawa by the solar X-ray.
• SPICE: the position and attitude data of Hayabusa spacecraft
• Shape Model: Very precise shape model of Itokawa created by using the data obtained by Hayabusa

The detailed things when the data is used are written in the Web site. We hope that the Hayabusa data archives are used for various kinds of research works.

Notice:
(1) All the level-1 data, which are close to the raw data, are opened to the public.
(2) For some instruments, the level-2 data, calibrated and/or included additional information,
are also available. We will add the level-2 data when they are ready.
(3) The precise shape model, which is not level-1 and level-2 data, is released.
(4) The detailed information related to these data will be uploaded when it is ready

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Examples of images of AMICA in the Hayabusa data archives

1.

Time (UTC): Oct. 18, 2005, 16:23

Distance : 5.9 km

The sticking rock in the lower middle is called "Pencil Boulder." Its shadow also can be seen clearly


2.

Time (UTC): Oct. 19, 2005, 12:22

Distance : 4.7 km

The smooth surface in the center is called "Muses-sea" (IAU official name is MUSES-C Regio).


3.

Time (UTC): Oct. 23, 2005, 12:16

Distance : 4.9 km

The smoothed area in the center is called "Uchinoura" (IAU official name is Uchinoura Regio).


4.

Time (UTC): Oct. 23, 2005, 16:17

Distance : 4.7 km

The gray rock at the top center is called "Black Boulder."


5.

Time (UTC): Nov. 9, 2005, 05:00

Distance : 0.65 km

In the left side, "Komaba crater" is seen. The smooth region upper right is "Muses-sea" (IAU official name is MUSES-C regio).


6.

Time (UTC): Nov. 12, 2005, 05:35

Distance : 0.11 km

The close-up image of rocks near "Komaba crater."

7.

Time (UTC): Nov. 19, 2005, 12:14

Distance : 1.0 km

The sticking rock in the lower left is "Pencil Boulder."





Notice: The images shown here are applied some image processing methods in order to be seen clearly. Such information like scales and positions on the surface is not included in the original image data.

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For inquiries:
JAXA Public Affairs Department
Tel: +81-3-6266-6413 to 7, Fax: +81-3-6266-6910

Source: JAXA press release

The Japanese Space Exploration Agency (JAXA) press release is reproduced below:

"Hayabusa" starts fully fledged return trip to Earth

April 25, 2007 (JST)

Japan Aerospace Exploration Agency (JAXA)

Since February 2007, JAXA has been carefully preparing to start the fully fledged return trip to Earth using the ion engine and one attitude control reaction wheels (as two of the three wheels are unavailable due to anomalies.) The Hayabusa's return to the Earth is scheduled for June 2010.

We have faced challenges during the preparation, for example, the establishment of the attitude control that can maintain the alignment of the ion engines thrust vector took more time than expected, and more study was required to set up the operation method of the ion engine in consideration of its aged deterioration. We are now ready to start the return cruise operation with countermeasures for these problems.

Therefore, we would like to announce that on 2:30 p.m. on April 25 (Japan Standard Time) the Hayabusa was shifted to the fully fledged phase for the return cruise to Earth.

The operation is still challenging as we have to carefully monitor the conditions of the only active reaction wheel, the ion engine, and onboard equipment. We will operate the Hayabusa with the greatest care and utmost effort.

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Mission website:
Asteroid Sample-return Spacecraft "Hayabusa"(MUSES-C)

For inquiries:
JAXA Public Affairs Department
Tel: +81-3-6266-6413 to 7, Fax: +81-3-6266-6910

Source: JAXA press release

Hayabusa leaves for Earth

Hayabusa spacecraft, which lost the functions of two of three reaction wheels and bi-propellant thrusters during the proximity operation around the asteroid Itokawa, sailed across the aphelion with the spin attitude stabilization in 2006. The trial and adjustment on the non-spin attitude control using both a single reaction wheel and the ion beam jets have been executed since February 2007.

The Hayabusa project team managed to acquire a skill to cancel the disturbance torque originated from an ion engine by means of the solar pressure and to establish the operational scheme. And then Hayabusa spacecraft stated the homeward journey with an ion engine driven on April 25 2:30PM, 2007 (JST) aiming at the Earth return in 2010. It stays at the heliocentric space of 81,000,000 km (0.54 AU) apart from Earth, and 154,000,000 km (1.03 AU) from Sun.

The project team will operate Hayabusa spacecraft paying attention to remaining lives of components and devices. The onboard microwave discharge ion engines have executed the following space operations as of April 30, 2007;
Thruster-A: stand-by
Thruster-B: 9,600 hours
Thruster-C: 6,500 hours
Thruster-D: 11,400 hours

Source: JAXA/ISAS - Space News

Successful re-ignition of Ion Engine C onboard Hayabusa

August 20, 2007 Updated
Successful re-ignition of Ion Engine C onboard Hayabusa
Hayabusa spacecraft had been on the way to Earth with the ion engines B and/or D powered on since April 2007, though it lost the functions of chemical thrusters and two of three reaction wheels at the proximity operation around the asteroid. At the rescue operation in 2006 the ion engine C was not confirmed to exhaust the plasma jet. On July 28, 2007 a series of the restoration works and a new operation sequence revived the ion engine C again, which are accelerating Hayabusa on behalf of the engines B and D aiming for the Earth return on 2010. Sharing the delta-V duty among the multiple engines will secure a safety flight for the homeward journey.

Because the severe solar radiation seemed to increase the temperature beyond the safety zone to prevent the fuel leak, Hayabusa was operated with the attitude leaned against Sun so as to avoid solar heat flux in May. It passed through the perihelion at the solar distance 0.95AU on June 7 without any problems. During this term the engine D accelerated continuously Hayabusa as scheduled. At the end of July after establishment of the safety temperature, the warming up of a power supply by electrical heaters during several days and a special operational sequence successfully ignited plasmas again in the engine C. Then the Hayabusa's acceleration was shifted from the engine D to C reserving the rest of operational life.

The turn-on of the engine C is good news for the homeward journey of Hayabusa, which is still frighten at additional malfunctions. Since May 2003 each ion engine has been operated in space as follows

Engine A: stand-by
Engine B: about 9,500 hours
Engine C: about 7,000 hours
Engine D: about 13,500 hours
Total: 30,000 hours

Hayabusa will continue the powered flight using the engine C till November this year and then change to the ballistic flight with hibernation mode.

Source: JAXA - Muses-C

Hayabusa Finished First Leg of Orbit Maneuver toward Earth

October 29, 2007 Updated

Hayabusa asteroid explorer had been executing the powered flight toward Earth using a single reaction wheel and the microwave discharge ion engines since April this year. The achievement of the first leg of orbit maneuver around the perihelion led Hayabusa into turning off them and shifting the spin mode from three-axis attitude stabilization on October 24, 2007 according to the plan. The ion engines generated 1,700 m/s delta-V with 31,000 hours in total accumulated operational time up to now and still keep good thrust performance and enough propellant.
Hayabusa will fly in ballistic manner with the spin axis tracking toward Sun by the solar pressure torque without any propellant consumption. And it will resume the orbit maneuver in the second leg from February 2009 aiming for Earth return on June 2010. The remaining delta-V toward Earth is only 400m/s.

Hitoshi Kuninaka .

Source: JAXA - Muses-C