Tag: Ryugu

Ryugu’s most primitive boulders

1:18 pm

In a just published paper scientists reveal how they think they have identified the oldest rocks on the rubble pile asteroid Ryugu, and found them to be distributed across the entire face of the asteroid.

These boulders are light enough that they would float on water.

Ryugu is thought to have initially formed as a fluffy planetesimal that coalesced from accumulated dust in the early Solar System, and subsequently underwent processes such as thermal evolution and compression. This parent body was then later destroyed in a collision and fragments of this reaccumulated into the asteroid. However, planetesimals have never been seen, so whether they really existed or what they may have looked like is one of the biggest challenges in understanding the planet formation process. The boulders discovered in this research are thought to be a material that most strongly retains the appearance of the fluffy planetesimals that triggered the birth of the planets in the Solar System.

Additionally, the data from all the scientific instruments onboard Hayabusa2 that were used to examine the surface of Ryugu revealed that fragments of material similar to those of the ultra-high porosity boulders are globally distributed over the asteroid surface, and may have been collected in the sample taken by Hayabusa2. If highly primitive material with the ultra-high porosity discovered here is also found in the collected samples, it will both clarify the formation and evolutional history of Ryugu’s parent body, and also provide evidence of planetesimal formation in the early stage of the Solar System formation process.

There is no word yet from the scientists studying the Hayabusa-2 samples on what they have found. This paper gives them an idea of what could be the most important type of rock to look for.

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Hayabusa-2 begins journey to two asteroids

7:59 am

On January 5, 2021, after successfully delivering its samples of Ryugu to Earth, Hayabusa-2 fired up its ion engines and began its ten-year journey to two different asteroids.

Hayabusa2’s first extended-mission destination is the roughly 2,300-foot-wide (700 meters) asteroid (98943) 2001 CC21, which the probe will fly by at high speed in 2026, if all goes according to plan. A more in-depth rendezvous with yet another space rock, 1998 KY26, is scheduled to follow in 2031.

In a previous post I had mistakenly left out the first target asteroid. However, their primary target remains the tiny 100-foot-wide 1998 KY26, since it is so small. This will be the first close-up view of such a small asteroid, in space. Since such asteroids are many, it will tell us much about the make-up and history of the solar system.

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First look at Ryugu samples

8:55 am

Japanese scientists have taken their first look at the Ryugu sample material brought back by Hayabusa-2 and found they resemble charcoal.

The samples Japanese space officials described Thursday are as big as 1 centimeter (0.4 inch) and rock hard, not breaking when picked up or poured into another container. Smaller black, sandy granules the spacecraft collected and returned separately were described last week.

…The sandy granules the Japan Aerospace Exploration Agency described last week were from the spacecraft’s first touchdown in April 2019.

The larger fragments were from the compartment allocated for the second touchdown on Ryugu, said Tomohiro Usui, space materials scientist. To get the second set of samples in July last year, Hayabusa2 dropped an impactor to blast below the asteroid’s surface, collecting material from the crafter so it would be unaffected by space radiation and other environmental factors.

Usui said the size differences suggest different hardness of the bedrock on the asteroid. “One possibility is that the place of the second touchdown was a hard bedrock and larger particles broke and entered the compartment.”

The analysis of these samples has only just begun. Dating them is likely next, and that will probably reveal some startling results.

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Samples from space!

9:16 am

Scientists from both the Japanese Hayabusa-2 mission to the asteroid Ryugu and the Chinese Chang’e-5 mission to the Moon announced yesterday the total amount of material they successfully recovered.

The numbers appear to diminish the Japanese success, but that is a mistake. Getting anything back from a rubble-pile asteroid that had never been touched before and is much farther away from Earth than the Moon was a very great achievement. The 5.4 grams is also more than fifty times the minimum amount they had hoped for.

This is also not to diminish the Chinese achievement, They not only returned almost four pounds, some of that material also came from a core sample. They thus got material both from the surface and the interior of the Moon, no small feat from an unmanned robot craft.

Scientists from both nations will now begin studying their samples. Both have said that some samples will be made available to scientists from other countries, though in the case of China it will be tricky for any American scientist to partner with China in this research, since it is by federal law illegal for them to do so.

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Scientists confirm ample Ryugu material in first Hayabuse sample chamber

8:01 am

Japanese scientists have opened the first chamber that stored the Ryugu asteroid samples obtained during its first touch-and-go sample grab, and confirmed that it holds ample material.

They also noted that the chamber itself contained gas from the asteroid as well.

The Japan Aerospace Exploration Agency (JAXA) has confirmed that the gas collected from the sample container inside the re-entry capsule of the asteroid explorer, Hayabusa2, is a gas sample originating from asteroid Ryugu.

The result of the mass spectrometry of the collected gas within the sample container performed at the QLF (Quick Look Facility) established at the Woomera Local Headquarters in Australia on December 7, 2020, suggested that the gas differed from the atmospheric composition of the Earth. For additional confirmation, a similar analysis was performed on December 10 – 11 at the Extraterrestrial Sample Curation Center on the JAXA Sagamihara Campus. This has led to the conclusion that the gas in the sample container is derived from asteroid Ryugu.

They think that this gas must have outgassed from the samples themselves. I suspect it was released either during the long journey or when the samples were subjected to the high accelerations and impact during its return to Earth. Research is going to have to try to pin this down, however.

They plan to open the two remaining sample chambers containing material sometime next week.

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Scientists confirm Hayabusa-2’s return capsule brought back material from Ryugu

8:56 am

Based on their first observations of the return capsule from Hayabusa-1, Japanese scientists yesterday confirmed that it successfully has returned material from the asteroid Ryugu.

JAXA said in a statement that they observed the sandy material at the entrance of the collection chamber, but have yet to look inside to see if more asteroid dust is lurking there. It is only the second time that scientists have returned material from an asteroid.

This find in the entrance portends a gold mine of material in the collection chamber itself.

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Hayabusa-2’s samples from Ryugu land in Australia

2:07 pm

The return capsule carrying the asteroid samples grabbed by Hayabusa-2 from Ryugu successfully parachuted down in the outback of Australia today.

Officials from the Japan Aerospace Exploration Agency, or JAXA, confirmed shortly after 1 p.m. EST (1800 GMT) that the Hayabusa 2’s nearly 16-inch (40-centimeter) sample carrier landed in Australia. Touchdown likely occurred several minutes earlier.

Recovery teams dispatched via helicopter began hunting for the 35-pound (16-kilogram) capsule using estimates of its landing site derived from a radio beacon signal. Mission managers expected it could take several hours to find the capsule and recover it. The landing occurred before dawn in Australia.

Since the article above was posted the capsule was located, and it was found much quicker than first expected.

This was the second sample return mission by the Japanese. The first, Hayabusa-1, successfully returned its capsule in 2010, but because of many technical problems during the mission it only brought back a few microscopic samples. In fact, the technical problems were so bad it was really a miracle the capsule came back at all.

Hayabusa-2 however has been a complete success, showing that they learned from the first mission and applied those lessons to the second.

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Hayabusa-2’s impactor shook Ryugu

8:26 am

When Hayabusa-2 fired an impactor into the asteroid Ryugu in order to access subsurface material in a sample grab, it apparently shook the asteroid, shifting boulders and rocks as far as 130 feet away.

The artificial impactor disturbed boulders within a 30m radius from the center of the impact crater- providing important insight into asteroids’ resurfacing processes.

Professor ARAKAWA Masahiko (Graduate School of Science, Kobe University, Japan) and members of the Hayabusa2 mission discovered more than 200 boulders ranging from 30cm to 6m in size, which either newly appeared or moved as a result of the artificial impact crater created by Japanese spacecraft Hayabusa2’s Small Carry-on Impactor (SCI) on April 5th, 2019. Some boulders were disturbed even in areas as far as 40m from the crater center. The researchers also discovered that the seismic shaking area, in which the surface boulders were shaken and moved an order of cm by the impact, extended about 30m from the crater center. Hayabusa2 recovered a surface sample at the north point of the SCI crater (TD2), and the thickness of ejecta deposits at this site were estimated to be between 1.0mm to 1.8cm using a Digital Elevation Map (DEM).

This data makes all the more important for OSIRIS-REx to get post-sample-grab images of its Nightingale site, if at all possible.

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Ryugu, like Bennu, appears to have rocks from other asteroids

9:21 am

Japanese scientists today announced that 21 rocks identified by Hayabusa-2 on the asteroid Ryugu have a composition that suggests they were formed on another asteroid.

Although Ryugu’s surface is uniformly dark [because it is a C-type asteroid], the scientists behind the new research found numerous boulders scattered across the asteroid that were 1.5 or more times brighter than their surroundings — that is, they reflected at least 50% more light than most of the rest of Ryugu. This contrast made the researchers suspect these boulders may have come from outside the asteroid.

By analyzing the spectrum of light reflected off 21 of these boulders, the scientists deduced they were made of minerals known as anhydrous silicates. Prior studies have suggested that such water-poor, silicon-rich rocks make up silicaceous or S-type asteroids, the most common kind of asteroid found in the inner main asteroid belt. The brightness of these boulders also matches the brightness of S-type asteroids.

This result compliments the result yesterday from scientists studying Bennu with OSIRIS-REx, and was in fact released at the same time. Both asteroids apparently contain material from other asteroids, suggesting that asteroids in their initial formation (as rubble piles) are routinely a mixture of material from many asteroids, thrown out during impacts and then recaptured.

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Hayabusa-2’s future asteroid targets

10:02 am

Link here. There are two prime candidate asteroid targets, both near Earth astroids.

The possible secondary targets include the oblong asteroid 2001 AV43 or the asteroid 1998 KY 26. They’re each about the size of a large house and both orbit the Sun in roughly 500 days. The proposed plan would see Hayabusa 2 arriving at 2001 AV43 in the late 2029 time frame, or reaching 1998 KY 26 in July 2031. Both asteroids have a low enough relative speed relative to the spacecraft to put them within (eventual) reach after Hayabusa 2’s December flyby.

Interestingly, 2001 AV43 will fly 313,000 km from Earth (0.8 times the Earth-Moon distance) on November 11, 2029.

The two asteroids were selected from an initial field of 354 candidates, which was winnowed down based on accessibility and scientific interest. Both are fast rotators, as evidenced by their light curves, each spinning on its respective axis once every 10 minutes. This represents the shortest “day” of any known object in the solar system, suggesting that these asteroids are in fact solid objects and not simply loosely aggregated “rubble piles.” A visit to one of these asteroids would mark the first time a space mission has seen such an enigmatic fast rotator up close.

The asteroid 1998 KY26 is also a possible carbonaceous (C-type) asteroid, and Hayabusa 2’s exploration of such a space rock would be another first.

Going to 1998 KY26 would also require a distant pass of another asteroid. Going to 2001 AV43 would require a fly-by of Venus, which could provide more data on that planet. Based on this information, my guess is that they will opt for 1998 KY26.

The decision must likely be made before Hayabusa-2 drops off its Ryugu samples to Earth on December 6, 2020.

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