Computer graphics show a small carry-on impactor firing a projectile into the surface of the Ryugu asteroid and the Hayabusa 2 probe collecting dislodged samples. (CG design by Masayuki Shirai)

The Hayabusa 2 space probe completed a three-and-a-half-year, 3-billion-kilometer journey to “spinning top” asteroid Ryugu, but now the hard part of its mission starts, the Japan Aerospace Exploration Agency (JAXA) said June 27.

“Frankly, I felt relieved,” Makoto Yoshikawa, mission manager and associate professor at the Institute of Space and Astronautical Science (ISAS) said of the probe’s arrival. “But there’s much more to come in the mission. The atmosphere here is tense.”

The Hayabusa 2 is scheduled to stay at Ryugu for about a year and a half, and land on the asteroid’s surface three times to collect samples before returning to Earth in 2020.

The samples could help solve some of the mysteries about how the solar system was formed. The samples could also contain organic substances that may help explain the origins of life.

The Hayabusa 2, which had been gradually slowing down, was operating normally and moving parallel about 20 km above Ryugu at 9:35 a.m. on June 27, JAXA’s project team confirmed at the ISAS control room in Sagamihara, Kanagawa Prefecture.

The Hayabusa 2 is the successor of the original Hayabusa probe, which returned to Earth in 2010 from the Itokawa asteroid. Although the mission was plagued with problems, the Hayabusa managed to bring to Earth the first-ever particles from an asteroid.

The Hayabusa 2 carries improved ion engines and communication equipment.

After being launched from the Tanegashima Space Center in Kagoshima Prefecture in 2014, the probe circled the sun and used the Earth’s gravity to propel it toward Ryugu, which passes near the orbits of Earth and Mars.

Although the asteroid is 300 million km from Earth, Hayabusa 2 covered 10 times that distance on its orbital journey.

After examining the geography and gravity of the minor planet, Hayabusa 2 is expected to land on Ryugu for the first time in autumn to collect samples from the surface.

Hayabusa is then scheduled to fire a metal fragment to create a hole in the surface and collect samples from inside the asteroid for the first time in history.

Ryugu’s shape resembles a spinning top and measures 900 meters in diameter. Its spin is relatively slow, taking about seven and a half hours for one rotation.

The asteroid’s surface is bumpy and features craters up to 200 meters in diameter.

Ryugu is believed to have emerged 4.6 billion years ago when the solar system was formed and may contain some of our world’s original building blocks.

Quelle: The AsahiShimbun


Hayabusa2 Rendezvous with Ryugu

June 27, 2018 (JST)

National Research and Development Agency
Japan Aerospace Exploration Agency (JAXA)

JAXA confirmed Hayabusa2, JAXA's asteroid explorer rendezvoused with Ryugu, the target asteroid.

On June 27, 2018, JAXA operated Hayabusa2 chemical propulsion thrusters for the spacecraft's orbit control.*

The confirmation of the Hayabusa2 rendezvous made at 9:35 a.m. (Japan Standard Time, JST) is based on the following data analyses;

  • ・The thruster operation of Hayabusa2 occurred nominally
  • ・The distance between Hayabusa2 and Ryugu is approximately 20 kilometers
  • ・Hayabusa2 is able to maintain a constant distance to asteroid Ryugu
  • ・The status of Hayabusa2 is normal

From this point, we are planning to conduct exploratory activities in the vicinity of the asteroid, including scientific observation of asteroid Ryugu and surveying the asteroid for sample collection.

*Hayabusa2 operation hours: 7:00 a.m. (JST) through 3:00 p.m. (JST), June 27. The thruster operation was pre-programmed in the event sequence earlier on the day and the command was automatically executed.


Optical Navigation Camera – Telescopic (ONC-T) image of Ryugu, photographed at 12:50 p.m. (JST), June 26, 2018.
ONC team (image credit): JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology,
Meiji University, University of Aizu, AIST.
(If a shortened credit is required, please us "JAXA, University of Tokyo and collaborators".)


The location of Hayabusa2 thrusters

A set of 12 thrusters is loaded with the Hayabusa2 spacecraft as circled in red.
Propulsion at 2.9 cm/s in the plus z-axis proceeded for the rendezvous.

Quelle: JAXA


Hayabusa 2's ion engines a huge improvement on predecessor's

The successful arrival on June 27 of the Hayabusa 2 explorer at the asteroid Ryugu after a 3.5-year journey spanning 280 million kilometers has proved the reliability and durability of the probe's ion engines -- a stark contrast to its predecessor's thrusters that were dogged by repeated serious trouble.

The scientist responsible for the ion engines' development and operation, associate professor Kazutaka Nishiyama of the Japan Aerospace Exploration Agency (JAXA), is proud of his brainchild's success. "The device is hard to break down," 47-year-old Nishiyama said.

The Hayabusa 2 ion engine uses ionized xenon gas to obtain propulsion power. As a thruster on Earth, it's very weak and only has enough power to move a one-yen coin, but its continuous use in space eventually accelerated the probe to a very high speed.

When using ionized xenon for propulsion, it has to be electrically neutralized, but on the first-generation Hayabusa three out of four neutralizers broke down or were degraded, pushing the project to the verge of a failure with the probe feared unable to return to Earth.

Nishimura was responsible for the original Hayabusa's troubled engine's operation, nursing the thruster back to a functional state on multiple occasions during his seven-year, 1,600-hour support of the spacecraft -- the longest period among project members. While working with the probe, Nishiyama developed a larger ion engine. Models of the neutralizers used on the Hayabusa 2 were continuously tested in a laboratory, stacking up 49,000 hours of operational time, more than double the original goal of 20,000 hours.

The Hayabusa 2 ion engine has proved stable in space, with the number of unscheduled shutdowns around one-fourth of the first-generation engine. Its operation for the outbound trip was suspended on June 3 as planned.

Nishiyama said of the thruster's successful performance, "The longer you move your own hands and operate the thing, the more you become confident. I believed that we would complete the outbound trip successfully. It all came down to putting the device together on Earth. I did everything I needed to do."

Nishiyama's ion engine will play a key role in bringing Hayabusa 2 back to Earth in 2020. "A device remains a toy if it cannot function in space," said Nishiyama, who is eager to prove the technology he developed in space. "The laboratory walls are not the limit of my work."


AXA associate professor Kazutaka Nishiyama, who developed the Hayabusa 2 probe's ion engine, poses for a photo behind a device testing ion engine neutralizers at the JAXA Sagamihara campus in Sagamihara, Kanagawa Prefecture, on June 19, 2018. (Mainichi)

Quelle: The Mainichi


Update: 2.07.2018


Stirling scientist in major international space mission

A University of Stirling scientist is set to begin analysing – and attempting to recreate – conditions on a primitive asteroid as part of a major international space mission led by the Japanese.

Dr Axel Hagermann, Associate Professor in Biological and Environmental Sciences, will spend the coming months assessing data from the Hayabusa2 mission – which is aiming to learn more about the origin and evolution of the solar system – after it entered into orbit around Ryugu earlier today [June 27].

Discovered in May 1999, Ryugu is a primitive, C-type asteroid – meaning its composition includes water and organics – and is part of the Apollo group of asteroids, regarded as potentially hazardous due to their close proximity to Earth.

Hayabusa2 is the first mission to an asteroid of this nature and only the second ever to return a sample from an asteroid, and experts believe it will provide an important insight into conditions in the early solar system.

Dr Hagermann – the only UK-based scientist on the mission – is co-investigator on the Thermal Infrared Imager, which will study the temperature and thermal inertia of the asteroid. He will also help analyse data from a radiometer on the German-built lander, Mobile Asteroid Surface Scout (MASCOT), and use this information to recreate the exact conditions of the asteroid surface in the Planetary Ices Laboratory at Stirling.

Dr Hagermann, a geophysicist who focuses on ice and its physical properties, explained: “As thermal measurements on an asteroid are very tricky, this approach allows us to ensure that the thermal measurements can be interpreted as accurately as possible.

“Thermal data from the asteroid surface are important because they allow us to constrain the surface material’s physical properties, confirm erosion – such as thermal cracking of rocks – and even explore minute changes in an asteroid’s orbit due to the way it re-radiates heat into space.”

The successor of Hayabusa, which returned to earth in 2010, Hayabusa2 is flown by the Japan Aerospace Exploration Agency in collaboration with the German Aerospace Centre and the National Centre for Space Studies in France. Launched in December 2014, the 600kg spacecraft features ion engines as well as state-of-the-art guidance and navigation technology, antennas and attitude control systems.

Now it has arrived, it will accompany Ryugu for approximately 18 months, observing the asteroid from around 20km, before releasing the lander onto its surface. In addition to the radiometer, MASCOT also carries an infrared spectrometer, a magnetometer and a camera, as well as an explosive device, to create an artificial crater to aid sampling.

The spacecraft is expected to return to Earth with samples by the end of 2020, allowing the team to clarify interactions between minerals, water and organic matter in the primitive solar system.

“By doing so, we will learn about the origin and evolution of Earth, the oceans, and life, and maintain and develop the technologies for deep-space return exploration,” Dr Hagermann added.

Dr Hagermann, who recently joined Stirling from Open University, is also currently working on the NASA InSight mission and will be involved in assessing data from the Heat Flow and Physical Properties Probe, better known as HP3. This work aims to piece together the story behind Mars’ origin and evolution by measuring the heat currently escaping through the surface of Mars.

Stirling’s involvement in Hayabusa2 is funded by the Science and Technology Facilities Council. HP3and MASCOT are led by the DLR Institute of Planetary Research Berlin.

Quelle: The University of Stirling