Asteroid Explorer "HAYABUSA" (MUSES-C) Topics

Topics List

Sep. 7, 2016 Updated
Submicrometer craters in samples returned from the asteroid Itokawa

It is previously reported that precious few Itokawa particles show submicrometer craters on their surface. An international research team led by Dr. Dennis Harries (Friedrich Schiller University Jena) has investigated these craters in details using scanning electron microscopy and transmission electron microscopy. As a result of their observations, 15 craters were confirmed on a new particle. Though particles showing such craters had also been found in previous studies, those particles showed only 1-2 craters on their surface. Thus, the new particle found by the research team shows unusual number of craters on the surface of one particle.
Also, the research team found that the crater was secondary craters formed by fragments produced by the impact process of a tiny celestial body on the surface of asteroid Itokawa.

Submicrometer craters in samples returned from the asteroid Itokawa

Jun. 22, 2016 Updated
Trace of Itokawa's Four Billion Years of History Found on Particles

A research team led by Aerospace Project Research Associate Toru Matsumoto of JAXA found that traces of more than four billion years of history up until now of the Asteroid "Itokawa" were recoded on the surface of particles that were recovered from Itokawa by the Asteroid Explorer “Hayabusa” to bring back to the Earth, and their surface patterns and marks were analyzed by the research team.
The research team observed the faint structure of the particle surface in details through X-ray microtomography (X-ray CT) and by scanning electron microscopes. As a result, the surface pattern that had been believed to be just one type was found to be at least four variations. One of them was found to stem from Itokawa's parent body. Some particles analyzed this time retain the pattern that was thought to be made over four billion years ago.
The research method this time can acquire a lot of information without hurting the precious particles. Therefore, this method will become an imperative first-step analysis skill when studying extraterrestrial objects.

Trace of Itokawa's Four Billion Years of History Found on Particles

Jun. 26, 2013 Updated
Particles captured on asteroid Itokawa on exhibition.

JAXA is exhibiting particles brought back to the Earth by the asteroid explorer “Hayabusa,” which returned in June 2010, at the National Museum of Nature and Science and at the Sagamihara City Museum thanks to their cooperation.

- National Museum of Nature and Science Permanent Exhibit
From July 17
Between 9:00 a.m. thru 5:00 p.m.
9:00 a.m. thru 8:00 p.m. on Fridays

- Sagamihara City Museum Limited-time Only Exhibit
From July 17 thru 28
Between 9:30 a.m. thru 5:00 p.m.
* To look through an optical microscope, advanced reservations or getting a numbered ticket is required.
* We can accommodate 840 people every day.
* You can look at the particles through the TV monitor in the exhibition room during the period when the museum is open.

Particles captured on asteroid Itokawa on exhibition.

Jan. 9, 2013 Updated
Second International AO for Hayabusa sample investigation

The international AO this time aims at contributing to the further development of global asteroid science by offering samples to international researchers. Please confirm the application conditions. We are waiting for your proposals.

Proposal dates:
From Feb. 12, 2013 thru 24:00 (Japan Standard Time or 15:00 UTC) on Mar. 9, 2013

Jan. 24, 2012 Updated
1st International Announcement of Opportunity for HAYABUSA Sample Investigation

Japan Aerospace Exploration Agency (JAXA) has been engaged in initial analysis* of Itokawa’s sample brought back by HAYABUSA. On this occasion we would like to inform you of offering the announcement of opportunity for HAYABUSA Sample Investigation.
Through the peer review, JAXA will provide HAYABUSA sample to researcher who submits research proposal in the framework of this Announce of 0pportunity (herein after referred as "AO"). This AO is planned to be conducted a few times.
The 1st International AO issues on January 24th 2012.

Aug. 26, 2011 Updated
American magazine "Science" features Hayabusa

JAXA is currently working on collecting and cataloging particles brought back by the sample return capsule aboard the asteroid explorer Hayabusa.
Initial analysis of the particles that are identified as rocks has been carried out by a electron microscope.
The renowned American magazine “Science” published part of the initial analysis result with a photo of a particle on the cover in the latest edition issued on August 26, 2011. The magazine features the Hayabusa carrying six theses on the explorer.

Jun. 13, 2011 Updated
HAYABUSA recognized by Guinness World Records

The Asteroid Explorer HAYABUSA, which returned to the Earth on June 13, 2010, after overcoming various difficulties during some seven years in space, marked the one-year anniversary of its homecoming.
The HAYABUSA was recognized by Guinness World Records as the first spacecraft to bring back matter from an asteroid. JAXA received a certificate for the achievement.

May 23, 2011 Updated
HAYABUSA project team recieved Wernher von Braun Memorial Award

On May 20th, the National Space Society presented the Wernher von Braun Memorial Award to the HAYABUSA project team at the 2011 International Space Development Conference (ISDC), held at the von Braun Center in Huntsville, Alabama. The award recognizes "the first round trip to and sample return from the surface of an object in solar orbit".

Mar. 11, 2011 Updated
Preliminary results of initial analysis of particles brought back by Hayabusa

Since late January 2011, JAXA has been engaging in an initial analysis of the particles in the sampler container which was brought back by the asteroid exploration spacecraft "Hayabusa,"and some of the results of the initial analysis were presented at the 42nd Lunar and Planetary Science Conference (LPSC).
As a result of analyzing the major elementary composition of the particles identified as rocky using the scanning electron microscope (SEM) observations, the material scientific properties of the particles are found to be consistent with those of a specific kind of stony meteorite. We also clarified that there are several minerals in most rocky particles and they have complex three-dimensional textures. Evidence of space weatherng effects and the result from the noble gas analysis have revealed that the particles originated from the surface of Itokawa.
JAXA is continuing irs initial analysis.

Nov. 16, 2010 Updated
Particles brought back by Hayabusa identified as from Itokawa

JAXA has been engaged in collecting and categorizing particles in the sampler container that were brought back by the asteroid explorer "HAYABUSA."
As a result of the scanning electron microscope (SEM) observations and analyses of the samples, about 1,500 grains were identified as rocky particles, and most of them were judged to be of extraterrestrial origin, and definitely from Asteroid Itokawa, after further study of the analysis results and comparison of mineral compositions.
Their size is mostly less than 10 micrometers, and handling these grains requires very special skills and techniques. JAXA is developing the necessary handling techniques and preparing the associated equipment for the initial (but more detailed) analyses of these ultra-minute particles.

Oct. 8, 2010 Updated
Electron microscopic photos of particles taken from the HAYABUSA capsule

JAXA is currently observing particles that were collected by a Teflon spatula from a sample container (*1) of the HAYABUSA at the Curation Center (*2) at the JAXA Sagamihara Campus. As a result of direct observations of specimens taken by the spatula through the Scanning Electron Microscope, we found many particles.
It is still too early to determine if those particles were from the asteroid “Itokawa” until we see the result of our scheduled initial analysis.

(*1) The sample container is a special container in the HAYABUSA’s capsule to store samples.
(*2) The Curation Center is a facility to accept, process, and keep specimens.

Aug. 19, 2010 Updated
Over 100,000 people witness the HAYABUSA capsule!

The total number of visitors to the Asteroid Explorer HAYABUSA’s capsule at the Sagamihara City Museum, Tsukuba Space Center, and Marunouchi OAZO reached 101,091 as we completed the exhibition in Marunouchi today. JAXA presented a commemorative gift to the 100,000th visitor, Moe Nakajima (11 years old.)
Parts of the HAYABUSA capsule will be exhibited at the National Museum of Emerging Science and Innovation between August 26 and 30, then at the JAXA Kakuda Space Center on September 11 and 12. For those who live near the venues, it is a nice chance to take a look at the capsule that traveled in space for seven years. Don’t’ miss this opportunity!

Jul. 8, 2010 Updated
Exhibition of the HAYABUSA capsule and other interesting things

This summer, we are exhibiting a part of the capsule of the Asteroid Explorer "HAYABUSA," which returned to the Earth on June 13, and other interesting things at the Sagamihara City Museum, JAXA Tsukuba Space Center, and at the OO square on the first floor of Marunouchi Oazo Building.
Why don't you come and witness the real capsule that came back to the Earth after seven years in space!

Jul. 5, 2010 Updated
Small particles found in the sample container of the HAYABUSA

Minute particles were confirmed in the sample container of the HAYABUSA, whose unpacking operation was started on June 24 (JST) at the Curation Center at the Sagamihara Campus. We are still unsure if those particles are something from the ITOKAWA or from the Earth, thus we will further examine them. (Image: opened sample container)

Jun. 24, 2010 Updated
Starting to open HAYABUSA sample container

A capsule of the Asteroid Explorer "HAYABUSA," which returned to Earth on June 13, was brought to the curation facility at the Sagamihara Campus to be inspected and disassembled.
From the 24th, we finally started to open the sample container in the capsule. It will take one week to complete the opening of the container.

Jun. 14, 2010 Updated
Welcome back HAYABUSA to Earth after overcoming various difficulties!

The Asteroid Explorer "HAYABUSA" successfully separated its capsule at 7:51 p.m. on June 13 (Japan Standard Time, the following times and dates are all JST,) and re-entered the atmosphere to complete its mission operation at 10:51 p.m.
After the landing, a helicopter searched for the capsule in the Woomera Prohibited Area, and at around 11:56 p.m. on the 13th, its location was confirmed.
For about seven years since its launch by an M-V Launch Vehicle in May 2003, the HAYABUSA successfully completed a great achievement by landing on the asteroid "ITOKAWA," gathering rocks there, and returning to the Earth with them while overcoming various troubles.
(Image: Earth image taken by Hayabusa)

Jun. 5, 2010 Updated
HAYABUSA heading to Australia

JAXA confirmed that the third trajectory correction maneuver (TCM-3) was successfully carried out for the Asteroid Explorer "HAYABUSA" at 1:44 p.m. on June 5 (Japan Standard Time.) This operation completed the guidance of the HAYABUSA from the Earth's outer rim to the Woomera Prohibited Area in South Australia.

Apr. 21, 2010 Updated
HAYABUSA's Sample Recovery Capsule to land on Earth on June 13

JAXA has been discussing with the Australian government the landing location for the Sample Recovery Capsule aboard the Asteroid Explorer "HAYABUSA," which is being carefully maneuvered for its return. As a result, we have received landing permission (the Authorized Return of Overseas Launch Space Object (AROLSO) from the Space Licensing and Safety Office (SLASO) of the Australian Government.
The HAYABUSA's capsule will enter the Earth's atmosphere at around 11:00 p.m. on June 13 (Japan Standard Time, or at 14:00 on the same day Universal Time, Coordinated) to land at the Woomera Prohibited Area in South Australia.
We will carry out a trajectory correction maneuver (TCM) for a few more times to make the landing as accurate as possible.
We have opened a special site for providing updated information about the HAYABUSA's trip home. In addition, the HAYABUSA project team Twitter has also started. We welcome your support messages to HAYABUSA and its project team. We are looking forward to hearing from you!

Mar. 1, 2010 Updated
HAYABUSA enters an orbit inside the Moon's orbit

HAYABUSA, which is traveling back to the Earth, is confirmed to have taken an orbit that runs inside of the Moon's orbit. The perigee of the current orbit is about 310,000 km from the Earth. In early March, we will temporarily stop the ion engine to estimate its precise orbit.

Jan. 14, 2010 Updated
HAYABUSA coming back to terrestrial gravitation realm! Soon to be home

The Asteroid Explorer "HAYABUSA," which is on its way back to the Earth,has gradually been changing its orbit to come closer to the Earth. The explorer is now confirmed to be on an orbit that passes through the inside of the terrestrial gravitation sphere (about 1.4 million km from the Earth.)
Currently, the HAYABUSA is flying about 60 million km away from the Earth. Its flight orbit is scheduled to be moved inside the moon orbit.

Nov. 19, 2009 Updated
HAYABUSA: Resumption of return cruise by combining two ion engines

On November 4, JAXA found that one of the main ion engines aboard the Asteroid Explorer “HAYABUSA” had autonomously stopped during the second propulsion period in its return cruise back to the Earth. As a result of studying the measures to cope with this situation, JAXA confirmed that we can gain thrust power that is equivalent to that of one engine by combining the neutralizer of the Thruster A and the ion source of the Thruster B.
We believe that the HAYABUSA will be able to maintain its current return schedule to the earth around June 2010 as long as we can sustain the current conditions and sequence of operation. We will attentively monitor its return trip.

Nov. 9, 2009 Updated
Asteroid Explorer "HAYABUSA" Ion Engine Anomaly

On November 4 (Wed., Japan Standard Time), the Japan Aerospace Exploration Agency confirmed that one of the main ion engines (Thruster D) of?the Asteroid Explorer “HAYABUSA” had automatically stopped due to a voltage increase triggered by degradation of the neutralizer. The HAYABUSA was in the second orbit shifting phase aiming to return to the Earth in June 2010. Since we found the anomaly, we have been trying to recover the engine while investigating the thruster; however, we have not been able to reactivate the engine yet.
JAXA is currently checking the status of the HAYABUSA and studying measures to help the HAYABUSA return to the Earth. We will inform you of the result as soon as it is determined.
Image: HAYABUSA Ion Engine (Thruster A to D)
Note) The image is an artist’s concept to show the three activated ion engines.

Mar. 3, 2009 Updated
14 new place names approved on ITOKAWA

The ITOKAWA asteroid that the HAYABUSA probed is a very small asteroid of about 500 meters, but it reveals a lot of features including large crags (boulders,) craters, and planes. The HAYABUSA project team named the geographical features and marks for the sake of their mission and research activities. Recently, 14 of them were approved by the International Astronomical Union (IAU.)

Feb. 4, 2009 Updated
HAYABUSA: Firing ion engine and starting second phase orbit maneuver to return to Earth

JAXA reignited the ion engine of the Asteroid Explore "HAYABUSA" for a powered flight at 11:35 a.m. on February 4, 2009 (JST.) The HAYABUSA arrived at the asteroid "ITOKAWA" in 2005 and is now scheduled to return to the Earth in June 2010.We will continue to gradually accelerate the HAYABUSA by the ion engine until around March 2010 to carry out the second phase orbit maneuvering for returning it to the Earth.

(The "HAYABUSA" landing on the asteroid "ITOKAWA" (Artist's concept) ©Akihiro Ikeshita)

Jun. 2, 2008 Updated
Hayabusa reached the farthest deep space

Hayabusa stays at 2.5AU from Earth beyond Sun at the end of May 2008. When we see Hayabusa from Earth, it can be seen at the position of 12 degree apart from Sun. On the other hand Hayabusa should glance at Earth of 8 degree from Sun.

<-1AU-> <-- 1.5AU-->
Earth ------------- Sun ------------------- Hayabusa

Due to such a long distance between Earth and Hayabusa the communication time lag reaches about 40 minutes. Hayabusa has kept its attitude in the spin stabilization without thrust by the ion engines since last October.
So, the Earth tracking center had caught intermittently the signal form Hayabusa on the particular occasion for the onboard antenna to point toward Earth in accordance with the spinning of 10-minute cycle. The small glancing angle between Sun and Earth from Hayabusa enables simultaneously both Earth pointing of the onboard antenna and Sun pointing of the solar array. As a result the continuous communication is established and will be kept by next March.

Hayabusa spacecraft in deep space restores its energy with low activity for Earth return. On the other hand the Hayabusa operation team on the ground has just started to prepare for the capsule retrieval.

Hayabusa Operation Team

Mar. 6, 2008 Updated
Hayabusa passed through the third aphelion of 1.63AU from Sun

Hayabusa asteroid explorer, under the ballistic flight in the spin attitude stabilization, passed through the third aphelion of 1.63AU from Sun on February 28, 2008.
During this time moment it had been saving electrical power consumption due to low luminosity on the solar arrays.
The Earth distance increases rapidly and will reach 2.5AU at the end of May.
Hayabusa will make a good turn around the fourth aphelion under the powered flight by the ion engine and will come back Earth in 2010.

Hayabusa Operation Team

Oct. 29, 2007 Updated
Hayabusa Finished First Leg of Orbit Maneuver toward Earth

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.

Aug. 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.

Apr. 25, 2007 Updated
Hayabusa leaves for Earth

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.

Apr. 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.

Jun. 2, 2006 Updated
"Science" magazine features results of "Hayabusa" observations

The asteroid probe "Hayabusa," which landed on the asteroid "Itokawa" last November, successfully turned on its ion engine, and it is now aiming to return to Earth in June 2010. The U.S. eminent scientific journal Science features the results of Hayabusa's scientific investigations in its June 2 edition. The "Hayabusa" observed Itokawa's shape, geographical features, reflectance, mineral composite, and gravity from an altitude of three to 20 km, and clarified the Itokawa's structure as a "pile of rubble." Science published seven Hayabusa-related essays, the first time for the magazine to feature a Japanese asteroid probe project. The Hayabusa project also received a "Space Pioneer Award" from the National Space Society of the United States at the International Space Development conference held in Los Angeles in May.

Nov. 12, 2005 Updated
MINERVA (micro-rover) released

We confirmed that MINERVA (micro-rover) released at 3:24 pm (Hayabusa onboard time). Detailed condition are still investigating. Hayabusa is now ascending to home position. (right) Itokawa's image captured at 1:40 pm JST. You can see the shadow of Hayabusa.

Oct. 26, 2005 Updated
Altitude Estimation using Navigation Camera

Hayabusa is equipped with a Light Detection and Ranging (laser altimeter) to measure the distance between an object and the satellite using a laser beam. In addition, we have considered another method to measure the relative position from the Itokawa using acquired images.


Oct. 25, 2005 Updated
The Current Status of the Near-Infrared Spectrometer (NIRS)

Hayabusa is equipped with the Near Infrared Spectrometer (NIRS) to inspect minerals on the surface of the asteroid. To date, the Hayabusa has carried out observations mainly around the equator of the Itokawa.


Oct. 17, 2005 Updated
Generating a shape model of the asteroid Itokawa using the Laser altimeter (LIDAR)

The shape of the Itokawa has been measured by the Light Detection and Ranging Sensor (LIDAR, or laser altimeter), part of the Hayabusa's onboard equipment. We can learn about the three-dimensional shape of the Itokawa through LIDAR observations.


Oct. 12, 2005 Updated
Global Mapping of Itokawa (the initial global shape model)

Numerical Shape Modeling of Itokawa
The detailed three-dimensional shape model of the asteroid Itokawa is currently under construction, based on the images taken by Hayabusa, in cooperation with the research group of the University of Aizu. The completed model will be utilized for descent operation for the sampling sequence on the asteroid surface, as well as for the mass and density estimation from the gravity measurement.
The initial global shape model was created by using images, taken by Hayabusa from the Gate Position, about 20 km from Itokawa. Figure 1 shows the three dimensional shape model reconstructed following the outermost rims of the asteroid in each image.
At this stage, the obtained model is expressed by only convex parts. Now we are updating this model by adding concave parts. Even a more detailed shape model is also under reconstruction in parallel by using the observed data at the Home Position, about 7 km from Itokawa.

Figure 1 Initial Shape model

To verify the initial shape model, images taken by Hayabusa and the CG images generated from the model are compared. In Figure 2, one can see that the rim profiles are consistent with each other very well.

Camera image taken
by Hayabusa
CG images based on
the reconstructed model
Figure 2 Comparison between the camera images taken by Hayabusa and the
CG images based on the reconstructed model

How to Reconstruct the Shape Model
The procedure to reconstruct the shape model is the following.
Step 1 : Possible projected volume of Itokawa is extracted from one snap image, since it may extend behind the asteroid.
Step 2 : By taking advantage of the asteroid rotation, images from various viewing angles are obtained. Those images can narrow down where the possible projected volume can exist on a single plane.
Step-3 : By extracting the projected volume of Itokawa on all the planes, the three dimensional shape model can be determined.

Figure 3 Extraction of existence area based
on outermost rim
Figure 4 Restriction of Possible Projected
Volume on a single plane

The process of shape reconstruction is shown in Figure 5. First, the outermost rim is extracted from each image.

Image taken by
Figure 5 Outermost Rim Extraction Results of Itokawa

The process to restrict the possible projected volume of Itokawa is shown in Figure 6. Each image is shown from the top of the view. The more images are used, the better the shape is constructed. Finally, the reconstructed shape model is shown by wire framing filled by polygons.

Figure 6 Process to Restrict the Possible Projected Volume

Oct. 3, 2005 Updated
Imaging and position keeping at the Gate Position

-Exposures at Gate Position
Since its arrival on September 12th at the Gate Position 20km from Itokawa, Hayabusa has made sufficient numbers of exposures from omni-directions in the equatorial plane.
This figure shows the exposure directions and distances of those exposures with respect to Itokawa.
Note Itokawa size is not in scale

-On the Web Release of High Resolution Data
Fortunately, Hayabusa has accumulated a lot of very valuable images and the other data so far. And the data amount increases day by day. They are really precious and may make a huge impact to the existing planetary science knowledge.
High resolution images themselves can be readily used for improper and inaccurate interpretation. And Hayabusa project intends to add adequate calibration and speculation to those data and will make them public later but in timely manner.
To this end, Hayabusa project for the time being will not release every detailed information. We in advance would appreciate the understanding of the Hayabusa supporters in the world.

-Station Keeping and Pointing to Itokawa
Hayabusa needs to point its High Gain Antenna to the Earth for data transmission, while it has to make their instruments?field-of-view directions to Itokawa by maintaining its relative position to both Itokawa and the Earth directions.
This figure shows how the Hayabusa has deviated from the Earth direction in angle. Yellow bands represent when Hayabusa captured Itokawa at their instruments?center while the high data transmission rate was maintained.

-Laser Altimeter and Image-based Pseudo Range
Hayabusa is equipped with a laser altimeter that measures the altitude with the accuracy of about 1 meter. (LIDAR RANGE) Hayabusa is also given an autonomous station keeping capability that outputs a pseudo range data based on the illuminated pixels area. (ONC-S) , which shows a sinusoidal behavior due to the rotation motion of Itokawa.
This figure shows both measurements well correlate with each other and accurate information has been obtained and accumulated.

Sep. 22, 2005 Updated
Proposal of the names of representative terrain on Itokawa

The IAU guideline says that terrain larger than about 100 meters shall have the names of gods, internationally well known places with significance to be approved. Hayabusa project team proposes following names for the major features on Itokawa. Smaller terrain will be given names based on the nicknames referred to by the Joint Science Team analysts.

Proposed names and the reasons:

Muses Sea is the smooth terrain and stands for ?USES-C? the project code of Hayabusa, at the same time, named after the expanse where the Greek goddesses Muses are.
Uchinoura Bay is a potential crater on Itokawa, named after the mother port (launch site) of Hayabusa in Kyushu island, Japan.
Woomera Desert is also a potential large crater on Itokawa, named after the intended recovery area of Hayabusa-carried capsule with sample, Woomera Prohibited Area (WPA) in Australia, the return port of Hayabusa.

Sep. 12, 2005 Updated
Hayabusa arrives Itokawa

Hayabusa arrived Itokawa on 10:00 am, 12 Sep (JST: Japanese Standard Time). Now Hayabusa hovers around 20 kilometers away from asteroid Itokawa.
This picture was taken at 8:35 am, 12 Sep (JST) just before the settlement by the visible imager AMICA. Field of view is two degrees.
The photo shows contrast of rocky and hilly region and smooth area, which may suggest the origin of this asteroid. This feature may be a key to consider Itokawa? origin and evolution.
The scientific observation will be conducted for about two months including sampling and topographic measurement.

Color composite image will be available soon.

The figure below shows the Doppler velocity difference between Itokawa and Hayabusa. The velocity dropped down to zero around 01:17 UTC. It indicates that Hayabusa fired its chemical propulsion thruster so that the relative velocity was canceled. Vertically approaching speed is taken in km/sec and is shown the doubled speed corresponding to a round trip measurement. Horizontally is shown the Universal Time (World Time: UTC) when the Doppler information was collected. Since radio travels for about 17 minutes from Hayabusa, the last firing occurred around 01:17 UTC. The resulted relative velocity was confirmed down to about 0.25 mm/sec.

Sep. 11, 2005 Updated
Itokawa Image on September 10

Hayabusa continues approaching Itokawa, and its image is growing day by day. The left image is taken at 15:00 UTC on September 10 by the visible imager, AMICA. The distance from Hayabusa to Itokawa is approximately 30 km. The right image was obtained at 16:42 UTC on the day. The left image shows different face from the last release. Itokawa rotates about 50 degrees between left and right images. Surface features are more clearly seen.

Images of Itokawa: Sept. 10 (1 deg. x 1 deg.)
Left: 15:00 UTC Right: 16:42 UTC

Sep. 10, 2005 Updated
Itokawa Image on September 9

Hayabusa continues approaching Itokawa, and its image is growing day by day. The left image is taken at 16:28 UTC on September 9 by the visible imager, AMICA. The distance from Hayabusa to Itokawa is approximately 70 km. The right image was obtained at 18:11 UTC on the day. Itokawa rotates about 50 degrees between left and right images, and the irregular shape of Itokawa is clearly seen. Some features such as craters are also seen in these images.

Images of Itokawa: Sept. 9 (25 arc-min x 25 arc-min)
Left: 16:28 UTC Right: 18:11 UTC

Sep. 9, 2005 Updated
Itokawa Image on September 7

Hayabusa continues approaching Itokawa and the image of it has grown day by day.

Itokawa : 9/4 02:36 UTC (1), 9/6 03:32 UTC (2). (25 x 25 arc-minutes)

Image of Itokawa : Sept. 7, 16:00 (3: raw, 25 arc-min x 25 arc-min) (4: processed)

The image 3 is what Hayabusa took for Itokawa at 16:00 UTC on September 7 by the Visible Imager, AMICA. The v-band (540nm) filter was used with a horizontal polarizer. Sun light illuminates Itokawa from a little left.
The image 4 was obtained via magnification, interpolation, sharpening and contrast emphasizing technique. The AMICA team today gave no particular comment about terrain or shade as for this image, while they looked at it carefully with calm but hectic discussion. The analysis does continue together with more images taken from now on.
The distance to Itokawa is about 220km and Hayabusa is approaching Itokawa at the speed of about 7 km/h.

Sep. 7, 2005 Updated
Hayabusa detects Itokawa's rotation

This animated image is built from the twenty images taken between 18:10, 5 Sep and 0:30, 6 Sep (JST).
Distance between Itokawa and Hayabusa is less than 700 kilometers at the start of imaging. In this time, Hayabusa was approaching Itokawa at approximately ten kilometers per hour.
Itokawa's rotation period is known to be approximately 12 hours by ground-based observations. This animation shows about an half period of rotation.
Rotational direction was found as expected.

Sep. 5, 2005 Updated
Hayabusa successfully captured Itokawa shape for the first time in space.

As of September 4th morning of 2005, Hayabusa is at approximately 1,000 km toward Earth with respect to Itokawa, a near Earth asteroid target of the spacecraft, with the approach speed of 10 km per hour. Hayabusa took a series of its Optical Navigation Camera aboard on the day and the photos revealed, for the first time in space, the shape information of Itokawa. Left one was taken when the brightness was at the top, while the right one was at the bottom. The upward direction here is almost identical to the north of the ecliptic frame.

[Itokawa Images : 9/4 02:36 UTC (left), 9/4 05:12 UTC (right).
(25 arc-minutes x 25 arc-minutes)]

The light curve plot below corresponds to the images above. The images that should be were estimated numerically and those well agree with one another. Note that the following model illustrates the shape model obtained based on the ground-based observations including radar measurement performed last year. (Courtesy JPL/NASA)

[Relative Brightness of Itokawa]

[Itokawa Shape predicted for Sept. 4th Imagery. Ref.Ostro, S.]

The photos actually taken this time supports the model built before launch and also shows the rotation axis is almost perpendicular to the ecliptic plane. This spin axis information also agrees with what was predicted before launch. It is not legible enough but the tip-to-tip length in left photo looks several hundred meters long. The rotation period was estimated about 12 hours before launch, and it well accounts for the observation.

Ostro,S.J., Benner L.A.M., Nolan M.C., Magri C., Giorgini J.D., Scheeres D. J., Broschart S.B., Kaasalainen M., Vokrouhlicky' D., Chesley S.R., Margot J.L., Jurgens R.F., Rose R., Yeomans D.K., Suzuki S., and De Jong E.M. (2004) Radar observations of asteroid 25143 Itokawa (1998 SF36). Meteoritics & Planetary Science 39:407-424.

Sep. 1, 2005 Updated
1,900 km to the Itokawa

JAXA cut off the ion engine of the Hayabusa on August 28, and shifted its flight mode to approaching the Itokawa over its ecliptic. At the end of operations on September 1, the distance to the Itokawa was 1,900 km and Hayabusa was moving toward it at a velocity of 18 km per hour. The photo is an image of the Itokawa taken by the onboard optical navigation camera (ONC-T) of the Hayabusa.

Aug. 26, 2005 Updated
Hayabusa's navigation camera photographed the "Itokawa"

The asteroid explorer "Hayabusa" is flying smoothly toward the asteroid "Itokawa" and is expected to arrive in mid September.

We have already released a photo of the Itokawa taken by the Hayabusa onboard star tracker on August 15, but another onboard camera, the thin optical navigation camera (ONC-T) also successfully took photos.

Photos taken on Aug. 23 and Aug. 24 are superimposed so that you can see the movement in comparison with fixed stars in the back.

The distance between the Hayabusa and the Itokawa at the time of the photo was less than 10,000 km, and it is about 330 million kilometers from earth.

Itokawa loci exposed with optically navigated trajectory (PDF : 50.0KB)

2005.8.23 (Click to Image)
2005.8.24 (Click to Image)

Nov. 16, 2004 Updated
Welcome to Japan!
The first Hayabusa International Symposium

The first Hayabusa International Symposium was held between October 20 and 22 and invited researchers from many countries including the US, Australia, Italy, and France.

After a report about the objective and current status of Hayabusa was delivered, presentations were made covering the broad areas of science and engineering concerning asteroid probes. They included the topic of research on a meteorite that is the basis of analysis for when a sample return mission is successfully achieved.

During the last session on the third day, participants discussed current ongoing asteroid probe projects such as the "Stardust" and "HERA" in view of future developments after Hayabusa.

The symposium was very beneficial to all involved.

A commemorative photo in front of the life-sized Hayabusa model.
Some 100 researchers got together from Japan and overseas.

May 20, 2004 Updated
The close shot of area surrounding Japan by Hayabusa just before it came closest to the Earth

The image was taken when Hayabusa flew over Japan just before it came closet to the Earth for its swing-by. It was taken at around 1:00 p.m. on May 19, and the distance to the Earth was about 60,000km. (This is the last frame of the animation published yesterday.)
We cannot see the Japanese archipelago as it was covered by clouds at the time, but you can find the Chinese Continent (the Shandong Peninsular) in the lower left. On the north-east side is a part of the Korean Peninsula, and the north side of the clouds is part of Hokkaido, the Kuriles, and Sakhalin.
The half-shaped typhoon No. 2 and 3 are also in the lower middle. The left is No.2 and the right is No. 3.

Earth images taken by Hayabusa after its Earth swing-by

These are images acquired by Hayabusa as it was going away from the Earth after its Earth swing-by. They were pictured by the onboard wide angle camera (ONC-W2).
All three onboard cameras functioned properly during the Earth swing-by maneuver.
The following are the time and date (Japan Standard Time) and the distance to the Earth for each shot.

(Image 1)
taken at 8:10 p.m. on May 19 from 95,000 km

(Image 2)
taken at 9:00 p.m. on May 19 from 110,000 km

(Image 3)
taken at 12:00 a.m. on May 20 from 160,000 km

May 19, 2004 Updated
Animation showing area around Japan taken by onboard camera of Hayabusa

This is an animation compiled by images of the area around Japan acquired by the onboard Asteroid Multiband Imaging Camera (AMICA). The camera has multiple color filters, but only one filter was used for the sequence shots, thus images are in black and white.
The 16 images that were used were taken at about five minute intervals around 12:30 p.m. on May 19. The animation shows that Hayabusa came from the direction of South East Asia going up north toward Japan. You can see two typhoons (Typhoon No. 2 and 3) coming closer to Japan and clouds of a front stretching over Japan.
The distance between Hayabusa and the Earth at that time was about 60,000 km.

The Earth taken by the optical navigation camera (a wide angle camera) (Animation)

Hayabusa is equipped with two kinds of cameras, a telephoto type and a wide angle type. Previously acquired images were all taken by the telephoto camera, but the wide angle one also took some shots of the Earth this time. Seven sequence photographs were converted into an animation.
In images taken by the wide angle camera, the Earth is smaller compared to that pictured in the telephoto one.
The images were acquired around 11:30 a.m. on May 19 (Japan Standard Time). The distance between Hayabusa and the Earth at that time was about 80,000 km, which is approximately twice as much as the altitude of a geostationary orbit.

The earth pictured by Hayabusa

This earth image was acquired by Hayabusa at 10:00 p.m. on May 18 (Japan Standard Time). The distancebetween Hayabusa and the earth at that time was about 295,000 km. As Hayabusa came closer to the earth, the image became much clearer than the one taken on May 17. It shows the Atlantic Ocean in the center.
The right is the African and European Continents. You can see the north east area of the African Continent, the Iberian Peninsula, and part of the United Kingdom. The left side is the South and North American continents. In the lower left corner, you can clearly see the north east area of the South American Continent. The central America area is covered by clouds, but you can see from Mexico to the central area of the United States, and Cuba.
The image was taken by the onboard Asteroid Multiband Imaging Camera (AMICA). It was composed of three individually filtered images.

May 18, 2004 Updated
Hayabusa acquired images of the earth and the moon.

Hayabusa, which is coming closer to the earth for a swing-by, successfully acquired images of the earth and the moon on the 16th and the 17th.

Earth image taken by Hayabusa

This earth image was acquired at 3:30 a.m. on May 17 (Japan Standard Time, JST). The distance between Hayabusa and the earth at that time was about 910,000 km. The image shows the south part of the North American Continent (Texas area) in the center, and you can also see the whole continent, the Pacific Ocean and the Atlantic Ocean in blue, and clouds over them.
The image was taken by the onboard Asteroid Multiband Imaging Camera (AMICA). It was composed of three individually filtered images

Moon image by Hayabusa (1)

This moon image was acquired at 8:30 p.m. on May 16 (JST). The distance between the moon and Hayabusa at that time was about 710,000 km.
The equator is in the center of the image, and the left is the north, and the right is the south. It is mostly the far side of the moon. A black spot on the upper right on the moon is a huge crater on the far side of the moon called "Mare Orientale (or Eastern Sea)". The upper part of this moon image shows a part of the Oceanus Procellarum (the ocean of Storms) on the front side of the moon. The blackish part on the lower right seems to be Apollo crater (a part of the South Pole - Aitken basin).
This image was taken by the onboard AMICA, and was composed of three individually filtered images.

Moon image by Hayabusa (2)

This moon image was acquired at 8:00 p.m. on May 17 (JST), about a day after the above image (1) had been taken. The distance between Hayabusa and the moon at that time was about 340,000 km.
The area covered by this photo is about the same as the above (1), but as the distance became closer, the image was zoomed and clear. The black spot on the lower left seems to be the Mare Moscoviense (Moscow Sea).
This image was taken by the onboard AMICA, and was composed of three individually filtered images.

May 10, 2004 Updated
Hayabusa (Earth Swing-by)

The following are related sites for the Earth swing-by and the Hayabusa.


Apr. 16, 2004 Updated
The rough shape of asteroid "ITOKAWA" was elucidated.

A recent radar observation clarified the rough shape of an asteroid called "ITOKAWA", where the MUSES-C (Hayabusa) is heading for. (Above photo)
A research group led by Dr. Steve Ostro of the NASA Jet Propulsion Laboratory carried out observations by transmitting radio waves to ITOKAWA from the radiotelescope at the Arecibo Observatory in Puerto Rico. (Photo on right) The radiotelescope is famous for having the largest diameter of 305 meters. Their research is to observe time of wave reflection and frequency gaps over a long time to study the shape and revolution of a faraway asteroid.

Hayabusa will carry out detailed observations for months after its scheduled arrival at ITOKAWA in the summer of 2005. The onboard high-performance camera will capture more precise images of the surface of ITOKAWA, which looks like a potato in the image data retrieved by the Arecibo Observatory’ s radiotelescope.
In addition, Hayabusa is expected to provide more detailed information on the origin of the solar system through observations by spectroscopy of several wave ranges including infrared rays and X-rays, and hopefully by bringing back a fragment of ITOKAWA.
Hayabusa will conduct an "Earth Swing-by" in May 2004 to project itself into the orbit of ITOKAWA.

Photo 1:Radar Observations Model of Asteroid "ITOKAWA"[Data by S. J. Ostro et al., Meteoritics and Planetary Science (in press)]
Photo 2:The radiotelescope at the Arecibo Observatory [Photo courtesy of the NAIC - Arecibo Observatory, a facility of the NSF]

Radar Observations Model of Asteroid ITOKAWA The radiotelescope at the Arecibo Observatory

Jan. 30, 2004 Updated
Hayabusa is flying smoothly

JAXA finished the running test of an ion engine, "µ10", which is the same type of the onboard engines of Hayabusa. The running hours reached 20,614 hours (or about 859 days), and that is about 7 times longer than that of one onboard engine of Hayabusa, or 1.3 times of the total operation hours expected for a mission. We will acquire data by analyzing the tested engine in details for ion engine development for future flights.

Nov. 6, 2003 Updated
Hayabusa is flying smoothly

The onboard ion engines of the Hayabusa are operating smoothly as the main propulsion system to travel among planets. To date, the total operation time of the three sets of ion engines has reached about 6,000 hours (2,000 hours per engine). The Hayabusa is currently flying about 7.2 million km away from the Earth in the same direction as the Earth's revolution. The Hayabusa is scheduled to gain more speed by "swinging by" the Earth in May 2004, and arrive at an asteroid called "ITOKAWA" in the summer of 2005.

Photos:(Left) Hayabusa (Right) Ion engine test operation