The Hayabusa-2 interplanetary station has begun the landing of the MINERVA-Ⅱ1 descent vehicles on the surface of the Ryugu asteroid. The modules have already successfully separated from the orbiter at an altitude of 55 meters, now the mission team is waiting for confirmation of the landing, according to (1,2,3) on the mission website.
The automated station Hayabusa-2 was launched into space in December 2014. Its goal is the delivery of soil samples from the asteroid 162173 Ryugu, which belongs to the class C asteroids. The device successfully arrived at the asteroid on June 27 and entered a stable 20-km orbit around it. In the next year and a half, the probe will explore Ryugu from orbit, and will launch the Mobile Asteroid Surface Scout (MASCOT) module on its surface, which has a spectrometer, magnetometer, radiometer and camera. It is assumed that when approaching Ryugu, the device will shoot at the surface with an SCI (Small Carry-on Impactor) device, consisting of a copper projectile and an explosive charge, thus researchers will be able to study the composition of the asteroid's top soil layer. After taking a soil sample from the Ryugu surface, the station will go back to Earth and drop a capsule with the asteroid's substance in December 2020. You can read more about the mission, its tasks and tools in our material "Collecting the Past Bit by Bit".
Earlier, the station had already mapped the asteroid's surface from a 20-kilometer orbit, as a result of which scientists from the mission team were able to build two three-dimensional models of the asteroid's rotation. At the end of July, the spacecraft approached the Ryugu surface up to six kilometers, and in early August, it dropped to a minimum height of 851 meters from the Ryugu surface as part of an experiment to study the gravitational field of the asteroid and survey its surface from close range... Also, a team of scientists recently posted the results of the first month of work in orbit around the asteroid, including a heat map of the Ryugu surface and an estimate of the amount of rocks, which allows us to talk about the reality of a collision of an asteroid with another large object in past. Between September 10 and 12, the probe made a test attempt to descend to the surface of Ryugu, but it was unsuccessful due to problems with the lidar.
On September 19, Hayabusa-2 began preparations for a new rendezvous with the Ryugu surface for the landing of two small descent modules MINERVA-II 1. The descent began on September 20, and the landing MINERVA-Ⅱ1 will take place today, September 21. The Rover-1A and 1B modules are hexagonal in shape and measure 18 centimeters across, 7 cm high and weigh about 1.1 kg each. Rover-1A has four cameras, Rover-1B has three, they are designed to create stereo images of Ryugu ground. The modules are capable of moving along the surface of the asteroid due to the hopping mechanism and are equipped with sensors for measuring the temperature of the ground, optical sensors, an accelerometer and a gyroscope. The mission team has already received confirmation of the successful separation of the modules from the orbiter at an altitude of 55 meters from the surface of Ryugu at 4:05 GMT and establishing communication with them, now it is necessary to wait for confirmation of a successful landing on Ryugu.
Diagram of landing MINERVA-II 1 modules on the surface of Ryugu
Two Japanese mini-robots MINERVA-II1A and MINERVA-II1B have successfully landed on the surface of the asteroid Ryugu. Both are in good condition and are transmitting photographs and data from the asteroid, according to the Japan Aerospace Exploration Agency (JAXA) website.
The sunlight produced white spots in the photo taken by the robot. Photo: twitter / haya2e_jaxa
The robots detached from the Japanese space probe Hayabusa 2 on September 21. At least one of them is now moving on the surface of the asteroid, the agency writes.
MINERVA-II1 are the world's first mobile exploration robots to land on the surface of an asteroid. Each robot weighs only one kilogram. For the first time, these robots were able to autonomously move and take photographs on the surface of an asteroid.
“I was so touched that these small self-propelled vehicles are successfully exploring the surface of an asteroid, because we could not do this 13 years ago. I was particularly impressed by the close-up imagery on the asteroid's surface, ”said Hayabusa 2 mission leader Makoto Yoshikawa.
In total, the Hayabusa-2 probe team has published three images taken by robots. The images turned out to be blurry, as one of them was taken by the robot during rotation, and the other - at the moment of jumping. In addition, they got color spots due to the reflection of sunlight.
“Although I was disappointed with the blurry image, the important thing is that it was made by a self-propelled vehicle. Moreover, the photograph taken at the moment the robot leaps onto the surface of the asteroid confirmed the effectiveness of such a movement mechanism, ”said Tetsuo Yoshimitsu, responsible for the MINERVA-II1 project.
What is Hayabusa 2's mission?
The Hayabusa 2 mission began in 2014. Its cost is $ 150 million. The Hayabusa-2 space probe flew to the asteroid Ryugu for three and a half years and reached it at the end of June.
The mission of the probe is to study the asteroid and deliver to Earth samples of the rocks that make up it. “First of all, we will study the surface topography very carefully. Then we will choose a landing site. It is there that rock samples will be collected, ”said project manager Yoshikawa.
The diameter of the asteroid Ryugu is about 900 meters, it makes a complete revolution on its axis in seven and a half hours. It is located 290 million km from the Earth. Hayabusa-2 will spend about one and a half years in orbit around Ryugu.
The MINERVA-II1A robot captured this photo after detaching from the spacecraft. In the lower right corner is the surface of the asteroid Ryugu. Photo: twitter / haya2e_jaxa
Ryugu belongs to the class C asteroids, which are considered relatively primitive. This means that on its surface there may be organic materials and hydrates. Study of chemical composition Ryugu could help scientists understand the early stages of solar system evolution.
Two small robots MINERVA-II1a and MINERVA-II1b successfully landed on the surface of the asteroid (162173) Ryugu. It happened on September 21, but it took a day and a half to confirm the descent and check the operability of the robotic systems. Now these rovers take pictures of the asteroid directly from its surface and send them to Earth. This was reported by the press service of the Japan Space Agency JAXA.
The robots were delivered to the asteroid by the Hayabusa2 apparatus. It is expected to return to Earth in December 2020 with samples of Ryugu rocks.
It is still very far from the end of the mission, but already now you can look at the photographs sent from the asteroid. Unfortunately, both rovers are not really cool photographers, so you can't really see anything on them. For example, here is a picture taken during MINERVA-II1a's jump from Hayabusa2 to an asteroid:
The picture is wildly blurry, as the apparatus rotated while moving. The lower bright spot is the asteroid Ryugu, and the upper blurred silhouette is the Hayabusa2 spacecraft.
A snapshot taken by another robot also after the separation from Hayabusa2 gives more insight into Ryugu:
The third shot was taken directly from Ryugu. It was sent by the MINERVA-II1a apparatus, known from the first blurred photograph:
Robots move around the asteroid by jumping. It was during such a maneuver that this picture was taken. The bright white spot is the Sun.
Of course, not everyone was happy with the quality of the photos. More precisely, nobody was happy. But the main thing is different. For example, Tetsuo Yoshimitsu, responsible for the robots MINERVA-II1, said about the importance of the mission:
Although I was disappointed with the blurry images, it is important that they were made by self-propelled vehicles. A photograph taken at the moment the robot jumps on the surface of an asteroid confirms the effectiveness of such a movement mechanism.
Tetsuo Yoshimitsu
Responsible for MINERVA-II1
What is Hayabusa2's mission?
The main goal of the mission is to investigate a specific asteroid Ryugu. The study will take place in two stages: photographing and sampling the asteroid's rocks. In the second case, an impactor will shoot from the Hayabusa2 spacecraft towards the asteroid. Upon collision with Ryugu, it will explode, and in its place will be a meter deep crater.
The mission was launched on May 9, 2014. Its total cost, according to NewScientist, is $ 150 million. That is, it is more than four times cheaper than the Zenit-Arena stadium eaten by cormorants.
As the name suggests, this is the second mission in the Hayabusa cycle. The first was launched in May 2003. Seven years later, a first-generation spacecraft delivered soil samples from the asteroid Itokawa. As it turned out, it has a very low content of chondrites. This suggests that the temperature on Itokawa has been above 800 ⁰C for a long time, and this is possible only if the asteroid was part of a much larger space object.
Why is the asteroid Ryugu so remarkable?
Almost nothing. It was opened in 1999 and is no more than 900 meters long. A very typical class C asteroid - the oldest asteroids. They are considered to be rather primitive. And this is where he is interesting. Its age is approximately 4.57 billion years, it originated with Solar system... During this time, Ryugu has hardly changed, unlike the planets. So scientists hope to use it to understand how our system was formed.
Timelapse of Hayabusa2 approaching Ryugu What are these robots?
Robots moving along the surface of the asteroid Ryugu look like flattened cylinders. Both are 18 cm in diameter and 7 cm in height. Each weighs 1.1 kg. They're lighter than the MacBook Air!
The black plates are solar panels. Both robots are equipped with cameras with wide-angle lenses, stereo cameras, and thermometers.
MINERVA stands for MIcro Nano Experimental Robot Vehicle for Asteroid. It doesn't sound very cool in Russian, and the first letters cannot be combined into something poetic: "Micro-nano experimental robotic vehicle for asteroids."
In addition to two MINERVA-II1 robots, there is a MINERVA-II2 robot on board the Hayabusa2. It will be launched onto an asteroid next year. It is one hundred grams lighter than its two counterparts, slightly smaller in diameter - 15 cm, but taller - 16 cm.
Positioning the MINERVA rover on spaceship Hayabusa2 The MINERVA-II2 has two cameras, an accelerometer, a thermometer, and optical and UV LEDs for lighting.
There is also a MASCOT robot on the spacecraft. It is larger, weighs almost 10 kg, and has an infrared spectrometer, magnetometer, radiometer and camera on board. For 16 hours, which will operate his non-rechargeable battery, he will explore the surface structure and its mineralogical composition, temperature and magnetic properties of the asteroid. The launch is scheduled for next week - October 3, 2018.
MASCOT Robot Very soon Ryugu will enter the orbit of the asteroid (162173) by an automatic interplanetary station (AMC) Japanese Aerospace Exploration Agency (JAXA) Hayabusa-2 (Jap. は や ぶ さ 2 - "Sapsan-2"). This station has been moving towards its cherished goal for more than three and a half years, and now it has almost reached it. Soon we will learn a lot about the asteroid (162173) Ryugu, but for now it is worth considering the Japanese device itself.
AMC "Hayabusa-2" as presented by the artist.
The station will explore (162173) Ryugu for more than a year, simultaneously launching four small probes onto its surface. In December 2019, if everything goes according to plan, the AMC will fly back to Earth with soil samples. And in December 2020, these samples will be delivered to Earth in a special capsule.
The purpose of AMC
The AMC's target is the asteroid (162173) Ryugu, or 1999 JU 3. The asteroid was discovered on May 10, 1999 as part of the LINEAR project at the Socorro Observatory. The celestial body received its name - Ryugu - in September 2015, and precisely because of the launch of a probe to it. This name comes from Japanese mythology, in which Ryugu-jo is the underwater palace-residence of the dragon Ryujin, the ruler of the underwater world and the sea element. According to legend, the palace is built of white and red coral in the deepest part of the ocean and is very richly furnished.
(162173) Ryugu is a typical near-Earth asteroid from the Apollo group. Belongs to dark spectral class C, subgroup (according to SMASS) - Cg. Asteroids of this class are characterized by very low albedo (0.03 - 0.10), the spectrum of the Cg subclass has bright features in the short-wavelength part (<550 нм) и становится плоским или слегка красноватым в остальной. Астероиды класса С очень распространены: более 75% всех известных астероидов принадлежат именно к этому классу.
(162173) Ryugu. In the near future, better images of this celestial body will be obtained. Credit: JAXA.
The size (162173) of Ryugu is estimated at 920 meters. By no means the largest asteroid known to us. Perihelion ( orbital point closest to the Sun) it is 0.96 AU, and the aphelion ( orbital point farthest from the Sun) - 1.42 a.u. Crosses the orbit of Earth and Mars. The period of rotation around its axis is 7.63 hours, and its axis of rotation is perpendicular to the orbit (ie, the asteroid rotates as if "on its side"). The period of revolution around the Sun is 1.3 Earth years.
Orbit of asteroid (162173) Ryugu (1999 JU 3).
Previous Japanese mission
Hayabusa 2, as the name implies, is not the first Japanese station launched to explore asteroids. The first Japanese station was the Hayabusa space station, launched on May 9, 2003 to the asteroid (25143) Itokawa. This asteroid, unlike (162173) Ryugu, has a smaller size and belongs to the class S. Both vehicles have a similar design.
Hayabusa in orbit (25143) Itokawa as seen by the artist. More details about the differences between the devices will be discussed later in the article.
The first Japanese station, Hayabusa, was launched from the Uchinoura Space Center in Kagoshima Prefecture using a Mu-5 solid-propellant launch vehicle (LV). The approach of the probe to the asteroid occurred in September 2005, but the soil was delivered to Earth only in the summer of 2010.
Moreover, this soil was delivered with grief in half: the specialists in charge of the mission faced a huge number of problems in the work of the AMC. During the flight to a celestial body, a strong solar flare occurred, which disrupted the operation of solar panels, and problems with ion engines also arose. This reduced the maneuverability of the vehicle to a minimum. Because of this, the spacecraft only reached the asteroid in September 2005, and not in July. But the problems with the probe did not end there. When "Hayabusa" flew (finally) to the asteroid, the experts discovered a new problem: several gyroscopes on the AMS broke down. After some time, the station began to approach the surface; in total, it had to carry out three short landings on Itokawa - one test and two regular ones. But the first landing was unsuccessful due to a series of failures. In addition, the device was supposed to release a tiny robot "Minerva" to the surface. This small cylindrical device (12 cm in diameter, 10 cm in length) was equipped with three cameras, solar panels and a transmitter. However, no connection with Minerva could be established. The device, according to experts, missed the asteroid and flew into space. The most recent planting involved a fresh attempt at surface sampling. But here, too, everything went wrong: at the moment of closest approach to the surface of the asteroid, a computer malfunction occurred, the device lost its orientation and damaged one of the engines. And after that, the specialists completely lost touch with him ...
After some time, the connection was still restored. But the ion engine could not be restarted until 2009, and all this for a long time, the return of the station with soil to Earth was a big question. But in June 2010, the station still flew to Earth, firing off a capsule with soil samples. The capsule landed in the vicinity of the Woomera test site, in southern Australia, and the Hayabusa itself burned up in the Earth's atmosphere, completing its long and difficult mission.
Return to Earth of the capsule with soil. Woomer's polygon. The picture was taken with a long exposure. Credit: NASA / Ed Schilling.
Hayabusa burned up in Earth's atmosphere ... Credit: Ames Research / NASA.
When creating the Hayabusa-2 AMS, the Japanese analyzed all the failures and accidents on the previous mission. And so far, fortunately, the new station has no problems.
Hayabusa-2
The station was designed and manufactured by the Japanese company NEC Toshiba Space Systems.
The Hayabusa-2 station was launched on December 3, 2014 from the Tanegashima Space Center cosmodrome, located in Kagoshima Prefecture. RN H-IIA was used for launch.
The launch weight is 609 kg. Dimensions - 1 × 1.6 × 1.25 m. The energy source is solar panels. At a distance of 1 AU solar panels will provide up to 2.4 kW of power, and in the aphelion of an asteroid (1.4 AU) - 1.4 kW.
Hayabusa-2 was equipped with four modified μ10 ion thrusters, each of which provides thrust up to 10 mN. On the previous AMS "Hayabusa" μ10 engines were also installed, but they had a lower thrust (8.5 mN each). The working body is xenon. The motor can operate in four switching steps with a power of 250 W / 500 W / 750 W / 1000 W (1 kW) at each step respectively. An improved system for supplying the working fluid to the engines was also installed on Hayabusa-2.
Ion engines are used as cruise engines. Shunting engines run on hydrazine.
Instead of the parabolic reflector antenna installed on the Hayabusa, a flat antenna (operating at 32 GHz) with a high gain was installed. A very similar antenna was installed on the Akatsuki AMC. The connection between the Earth and the apparatus will be maintained in the Ka-band. However, Japan does not have enough of its own stations for receiving / transmitting signals in this range, so for communication the Japanese mainly use NASA's deep space communications network (DSN) and the European space communications network ESTRACK.
AMC "Hayabusa-2" during assembly. Credit: JAXA / NEC.
ASC "Hayabusa-2" during the approach to the asteroid in the artist's view.
The orientation system was also improved on Hayabusa-2. New, more reliable gyroscopes were installed. And now there are four of them at once, and not three, as it was on the Hayabusa.
The AMC has an all-metal shock charge Small Carry-on Impactor (SCI), consisting of a copper projectile and an explosive charge (plasticized HMX) to form an impact nucleus. The entire mass of SCI is 18 kg, of which 4.7 kg are explosives. The mass of the copper plate, from which the impact core will be formed, is 2.5 kg. The charge would have to form an artificial crater, exposing deeper material. The station will investigate this material in the future. For safety reasons, Hayabusa-2 itself at this moment will be in the shadow of the asteroid, and the explosion will be carried out on its illuminated side (ie, on the opposite side from the AMS). Therefore, the station will not be able to observe the explosion. But what should be done? To observe the explosion, the station will release a special device - DCAM 3, there will be a camera on it. DCAM 3 will transmit the image to the Hayabusa-2 AMS itself, and it will already transmit data to the Earth. DCAM 3 will begin surveying (162173) Ryugu from the moment it separates from AMC.
The DCAM 3 device, which is separated from the AMC, is based on the IKAROS probe. And the latter, by the way, was tested in space just a few years before the launch of Hayabusa-2.
IKAROS model at the 61st International Astronautical Congress. Prague. Credit: ISAS / JAXA / Pavel Hrdlička.
A lot of cameras were installed on Hayabusa-2: three optical navigation cameras (ONC-T, ONC-W1, ONC-W2), a CAM-C on the sampler and a thermal-infrared camera (TIR). The latter is a thermal imager, that is, it can determine the surface temperature (162173) Ryugu. There is also a lidar and a spectrometer.
Optical navigation cameras (eng. Optical Navigation Cameras, ONC) are used for remote sensing, as well as when the station approaches (162173) Ryugu. The ONC-T camera has a 6.35 ° × 6.35 ° field of view and a filter system. ONC-W1 and ONC-W2 are already wide-angle cameras (65.24 ° x65.24 °), operating in the range from 485 to 655 nm.
Near infrared spectrometer (eng. Near-Infrared Spectrometer, NIRS3) is designed to analyze the composition of the asteroid's matter.
Thermal imager TIR (eng. Thermal-Infrared Imager) will be used to determine the surface temperature (162173) of Ryugu in the range of -49 to 150 ° C (224-423K). The temperature is determined using a two-dimensional microbolometric grating. TIR spatial resolution is 20 m at 20 kilometers and 5 cm at 50 meters.
Lidar device measures the distance from the spacecraft to the surface of the asteroid. The principle of operation is as follows: a directed beam from a radiation source is reflected from a target (surface of an asteroid), returns to the source and is captured by a highly sensitive receiver; the response time is directly proportional to the distance to the surface. And if you know the response time and the speed of light, then you can easily determine the distance from the surface of the asteroid to the probe.
Soil sampling system similar to that installed on the Hayabusa, but is, unsurprisingly, more perfect. The collection will take place using a special sampler, which is a special tube. When the AMC touches the surface of the asteroid with it, the automation will fire a special cone-shaped tantalum projectile inside the tube. The projectile, which has a mass of five grams, will crash into the asteroid's surface at a speed of 300 m / s and lift part of the regolith. The latter, moving under microgravity conditions, will independently fall into a special collection. But even if this mechanism does not work, then the possibility of collecting samples still remains: the engineers additionally installed another special mechanism that can pick up and raise the regolith.
A special chamber was also installed on the sampler CAM-C... It will record the process of collecting regolith by the station.
Landing Probes
Hayabusa-2 will launch several miniature probes to the surface of the asteroid at once, some of them are placed in special containers: MINERVA-II-1 (contains ROVER-1A and ROVER-1B), MINERVA-II-2 (contains ROVER-2) and MASCOT. The AMS will leave them 60 meters above the asteroid. After that, the containers will begin to slowly descend to the surface (if their speed is less than the first space speed for (162173) Ryugu). The acceleration of gravity on such a small celestial body is very small, so the devices are not in danger.
ROVER-1A and ROVER-1Bdesigned by JAXA and Aizu University are cylindrical with a diameter of 18 cm and a height of 7 cm. Each device weighs 1.1 kg. They have two cameras (wide-angle and stereo cameras) and a thermometer. But even more interesting is how they will move along the surface of the asteroid. Inside them are small electric motors, on the axis of which an eccentric is installed. The rotation of a motor with an eccentric leads to a change in the center of gravity, and under the action of inertia, movement occurs: the devices bounce over the surface, so that they can safely move along it in microgravity conditions.
The MINERVA-II-2 container will accommodate ROVER-2... This device was developed by several universities, led by Tohoku University. It is an octagonal prism that, like the ROVER-1A and ROVER-1B, can move on the surface. The diameter of the circumscribed circle around the base is 15 cm, the height is 16 cm. The mass is 1 kilogram. It has two cameras, a thermometer and an accelerometer, and also has LEDs operating in the visible and ultraviolet ranges. They are designed to illuminate the dust flying over the asteroid.
The power source for all these devices is solar panels.
MASCOT (eng. Mobile Asteroid Surface Scout) Is the largest lander of all. It has larger dimensions: 29.5 × 27.5 × 19.5 cm. Weight - 9.6 kg. MASCOT is equipped with an infrared spectrometer, magnetometer, radiometer and camera. Able to move along the surface of the asteroid in the same way as other probes. It was developed by the German Center for Aviation and Space (DLR) in conjunction with the French National Center for Space Research (CNES). The device has a lithium-ion battery, its charge should be enough for 16 hours of continuous operation.
All these devices will communicate with the Earth, as is the case with DCAM 3, via AMC.
Conclusion
Thanks to the Hayabusa-2 AMS, people will be able to learn a lot of new things, albeit about a small, but unusual and interesting world. New knowledge will help us learn a lot about the solar system, for example, about its evolution. JAXA has already stated that it wants to try to find organic molecules on (162173) Ryugu. Scientists, finding / not finding them, will be able to understand more about the role of asteroids in the origin of life on Earth.
The Japanese, having analyzed all the shortcomings of the previous mission, created a new, more reliable apparatus. The station still has a lot of work to do, but there are no problems with it yet. Let's hope there won't be any.
17:23 28/09/20180 👁 880
AstronomyCosmonauticsHayabusa-2 Adventure 16:40 28 Sep. 2018 Complexity 3.1 The Hayabusa-2 probe has sent the most detailed image of the surface of the asteroid Ryugu Image of the surface of Ryugu obtained by the ONC-T Hayabusa-2 camera from a distance of 64 meters. JAXA, University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, Aizu University, AIST
The interplanetary station Hayabusa-2 sent the most detailed photograph of the surface of Ryugu to date, taken during the landing of MINERVA-Ⅱ 1. It turned out that the surface layer of Ryugu consists of larger particles than the soil of the Itokawa asteroid studied by the Hayabusa mission. reported in a press release on the mission website.
The automatic interplanetary station Hayabusa-2 was launched into space on December 3, 2014 and is designed to deliver soil samples from the near-earth asteroid 162173 Ryugu, which belongs to the C-class asteroid. him. According to the plan, the scientific program of the mission will last a year and a half, during which the device will explore Ryuga from orbit, and also, during approaching it, will shoot at the surface with an SCI (Small Carry-on Impactor) device, consisting of a copper projectile and an explosive charge, thus researchers will have the opportunity to study the composition of the asteroid's upper soil layer, and will also launch the MASCOT (Mobile Asteroid Surface Scout) and MINERVA-Ⅱ 2 descent modules onto its surface. After taking a soil sample from the Ryugu surface, the station will go back to Earth and drop a capsule with asteroid matter in December 2020 year. You can read more about the mission, its tasks and tools in our material "Collecting the Past Bit by Bit".
On September 21, 2018, the Hayabusa-2 station descended to a height of 55 meters from the Ryugu surface and dropped two small MINERVA-II 1 descent modules onto it. The Rover-1A and 1B modules each have a diameter of 18 centimeters, a height of 7 centimeters and a weight of about 1.1 kilograms. They are equipped with cameras, sensors for measuring ground temperature, optical sensors, an accelerometer and a gyroscope and are able to move along the surface of the asteroid using a hopping mechanism. On September 22, confirmation of the successful landing of modules came to Earth, which are now in working order and are sending new photographs taken during movements on the surface of Ryugu.
During the descent, when Ryugu was 64 meters away, the orbiter was able to obtain with the help of its on-board ONC-T (Optical Navigation Camera - Telescopic) camera the most detailed image of the asteroid's surface, uneven and dotted with boulders of various sizes. Subsequently, another ONC-W1 camera acquired an image of a larger area from a distance of 70 meters from the asteroid's surface. The predecessor of Hayabusa-2, the Hayabusa (or MUSES-C) mission, which operated in 2003-2010 and explored the near-Earth asteroid S-class (25143) Itokawa, received the clearest image of its surface from a distance of 63 meters, which can be seen that, unlike Ryugu, the surface layer of Itokawa consists of smaller particles, ranging in size from a few millimeters to several centimeters.
Hayabusa-2 is neither the first nor the last soil survey project. July 2005 surface survey