Itokawa / Hayabusa

[bystander]

Hayabusa2 Team Prepares for Asteroid Sample Collection
Planetary Science Institute | 2018 Oct 25

This image of asteroid Ryugu was taken with Hayabusa2's ONC-T (Optical Navigation Camera-Telescopic) on October 15, 2018 from an altitude of 42 meters. Image credit: JAXA, Tokyo University, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji Univeristy, Aizu University, and AIST.

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JAXA’s (Japan Aerospace Exploration Agency’s) Hayabusa2 mission is on track to return samples from its target asteroid, 162173 Ryugu, a C-type Near Earth Asteroid (NEA). The past month has seen the successful deployment of two rovers and a lander. The mission focus is now on the successful retrieval and return of a surface sample.

Two members of the Planetary Science Institute’s (PSI’s) science staff are on the Hayabusa2 science team as part of NASA’s Participating Scientist program, a cooperative effort between NASA and JAXA. Deborah Domingue is a member of both the Optical Navigation Camera (ONC) and Near Infrared Spectrometer (NIRS3) instrument teams. Lucille Le Corre is a Co-Investigator on the ONC team. Their focus, over the past several months, has been in support of data processing and analysis of Hayabusa2 data for landing site selection.

The Hayabusa2 engineering team’s safety constraints restrict where the spacecraft can safely touch down. These constrains include regions of 100 meter diameter with an average slope less than 30 degrees, boulder heights less than 50 centimeters, and an absolute temperature less than 370 degrees Kelvin (97 degrees Centigrade). This limited the selection to a region plus or minus 30 degrees from the equator. The challenge of the science team was to find a region of scientific interest that meet the engineering constraints.

The biggest hurdle seems to be finding regolith in a place that is comprised of boulders less then 50 centimeters, within a 100 meter diameter region. The lack of a powdered, fine-grain regolith on asteroid Ryugu will make it difficult for the Hayabusa2 spacecraft to collect a sample to be returned to Earth. ...

[bystander]

Researchers find water in samples from asteroid Itokawa
Arizona State University | 2019 May 01

Up to half of Earth's ocean water may have come from impacts by asteroids

The samples studied by Jin and Bose came from the feature called the Muses Sea, which is the smooth area in the middle of Itokawa. (Credit: JAXA)

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Two cosmochemists at Arizona State University have made the first-ever measurements of water contained in samples from the surface of an asteroid. The samples came from asteroid Itokawa and were collected by the Japanese space probe Hayabusa.

The team's findings suggest that impacts early in Earth's history by similar asteroids could have delivered as much as half of our planet's ocean water. ...

In two of the five particles, the team identified the mineral pyroxene. In terrestrial samples, pyroxenes have water in their crystal structure. Bose and Jin suspected that the Itokawa particles might also have traces of water, but they wanted to know exactly how much. Itokawa has had a rough history involving heating, multiple impacts, shocks and fragmentation. These would raise the temperature of the minerals and drive off water.

To study the samples, each about half the thickness of a human hair, the team used ASU's Nanoscale Secondary Ion Mass Spectrometer (NanoSIMS), which can measure such tiny mineral grains with great sensitivity.

The NanoSIMS measurements revealed the samples were unexpectedly rich in water. They also suggest that even nominally dry asteroids such as Itokawa may in fact harbor more water than scientists have assumed. ...

New clues to ancient water on Itokawa ~ Ziliang Jin, Maitrayee Bose

• Science Advances 5(5):aav8106 (May 2019) DOI: 10.1126/sciadv.aav8106

[bystander]

The Near-Earth Asteroid Ryugu – A Fragile Cosmic 'Rubble Pile'
German Aerospace Center (DLR) | 2019 Aug 22

Ryugu at night – a 'cauliflower rock' with bright minerals
Credit: MASCOT/DLR/JAXA

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In the summer of 2018, the asteroid Ryugu, which measures only approximately 850 metres across, was visited by the Japanese Hayabusa2 spacecraft. On board was the 10-kilogram German-French Mobile Asteroid Surface Scout (MASCOT) - a lander no bigger than a microwave oven and equipped with four instruments. On 3 October 2018 MASCOT, operated by the control centre at the German Aerospace Center (Deutsches Zentrum fur Luft- und Raumfahrt; DLR) in Cologne, separated from its mother craft 41 metres above the asteroid.

It touched down on the surface for the first time six minutes after deployment, before coming to a halt 11 minutes later, like a dice on a board game moving in slow motion. Over the course of 17 hours, MASCOT carried out experiments in various places amid the large boulders.

Evaluation of the image data from DLR's MASCOT camera (MASCam) showing the descent and Ryugu's surface has now revealed a detailed view of a fragile 'rubble pile' made up of two different, almost black, types of rock with little internal cohesion. The scientific team, led by planetary researcher Ralf Jaumann from the DLR Institute of Planetary Research in Berlin-Adlershof, have now reported on this in the current issue of Science.

"If Ryugu or another similar asteroid were ever to come dangerously close to Earth and an attempt had to be made to divert it, this would need to be done with great care. In the event that it was impacted with great force, the entire asteroid, weighing approximately half-a-billion tonnes, would break up into numerous fragments. Then, many individual parts weighing several tonnes would impact Earth," says Jaumann, who is supervising the MASCam experiment, interpreting the observations.

The asteroid is very similar to carbonaceous meteorites found on Earth, which date back 4.5 billion years. With an average density of just 1.2 grams per cubic centimetre, Ryugu is only a little 'heavier' than water ice. But as the asteroid is made up of numerous pieces of rock of different sizes, this means that much of its volume must be traversed by cavities, which probably makes this diamond-shaped body extremely fragile. This is also indicated by the measurements conducted by the DLR MASCOT Radiometer (MARA) experiment, which were published recently. ...

Images from the surface of asteroid Ryugu show rocks similar
to carbonaceous chondrite meteorites ~ R. Jaumann et al

• Science 365(6455):817 (23 Aug 2019) DOI: 10.1126/science.aaw8627

[neufer]

Click to play embedded YouTube video.

[bystander]

JAXA: Hayabusa2 Departs from Ryugu
Japanese Aerospace Exploration Agency | 2019 Nov 13

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

[neufer]

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

Click to play embedded YouTube video.

Replica of Hayabusa's sample-return capsule (SRC) used for re-entry.

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<<[Hayabusa2] collected and stored the samples in separate sealed containers inside the sample-return capsule (SRC), which has a thermal insulation, 40 cm external diameter, 20 cm in height, and a mass of ~16 kg. In November 2019, Hayabusa2 used its ion engines to leave orbit [with a velocity change of 9.2 centimeters per second] and return to Earth.

When Hayabusa2 flies past Earth in late 2020, it will release the capsule spinning at one revolution per three seconds. The capsule will re-enter the Earth's atmosphere at 12 km/s and it will deploy a radar-reflective parachute at an altitude of about 10 km, and eject its heat-shield, while transmitting a position beacon signal. The sample capsule is planned to land at the Woomera Test Range in Australia. Once on Earth, any volatile substance will be collected before the sealed containers are opened. The samples will be curated and analyzed at JAXA's Extraterrestrial Sample Curation Center, where international scientists can request a small portion of the samples.

After the spacecraft returns and flies past Earth to deliver the sample capsule in late 2020, it is expected to retain 30 kg of xenon propellant, which can potentially be used to extend its service and flyby new targets to explore. One prime candidate is asteroid 2001 WR1 for a flyby on 27 June 2023.>>

[neufer]

Click to play embedded YouTube video.

<<In 2019, the Japanese Space Agency mission Hayabusa2 shot a 2 kg copper slug at more than 7,000 kph into the tiny asteroid Ryugu to understand its surface better and to be able to access subsurface materials. A camera about a kilometer away caught the action as material was ejected in plumes from the crater. The video plays twice at 1 second per frame, then plays twice at 2 seconds per frame. The left is full view, the right zoomed in (the scale bar is 25 meters wide).>>

[neufer]

Click to play embedded YouTube video.

[bystander]

Hayabusa2 Re-entry Capsule Approved to Land in Australia
Japan Aerospace Exploration Agency | 2020 Aug 18

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The Hayabusa2 re-entry capsule will return to Earth in South Australia on December 6, 2020 (Japan Time and Australian Time). The landing site will be the Woomera Prohibited Area. The issuance of the AROLSO gave a major step forward for the capsule recovery. ...

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A member of the recovery team transports the Hayabusa-2 sample capsule recovered from the Australian desert to a secure facility on Dec. 6. (JAXA)

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Early the morning of Dec. 6, Japan's sample-return mission successfully delivered fragments of the asteroid Ryugu by capsule and parachute over the Australian Outback.

Written By: Bob King for the Duluth News Tribune
Dec 6th 2020 - 3pm.

<<A brilliant fireball streaked above Australia's southern Outback early Sunday morning (Dec. 6) as a 16-inch metal capsule plummeted to Earth. Inside were fragments of a small, near-Earth asteroid painstakingly-gathered by Japan's Hayabusa-2 probe. As the capsule reached speeds of more than 26,000 mph, the heat shield's temperature climbed to 3000° C, yet the samples remained cool and secure.

The pod landed safely on the red, sandy ground, its parachute hung up in a tree . A helicopter crew was dispatched and tracked its radio beacon until they made a visual sighting of the landing site. The treasure chest held two separate samples of Ryugu, a dark, "rubble-pile" asteroid 1 km across and currently about 11.5 million km from Earth.

Why go to all the trouble and expense of flying to asteroids when meteorites — fallout from asteroid collisions — are delivered to Earth every year for free? The reason is that falling fragments are less pristine. They're heated during their atmospheric plunge, which releases crucial volatiles, gases and compounds that easily vaporize. Often, meteorites are found days to weeks after they fall, during which time they become contaminated with earthly gases, water and chemicals in the soil. When you go directly to the source and gather specimens in situ, you get true raw material. Among other things, Japanese scientists will also be looking for traces of ancient water in the samples. While comets delivered some of Earth's current water during its tumultuous youth 4.6 billion years ago, asteroids appear a more likely source because the kind of water they possess is a better match.

While the capsule journeys back to Japan, the spacecraft is already off on a second quest. 11 years from now Hayabusa-2 will pay a visit to the near-Earth asteroid 1998 KY₂₆, which measures just 30 meters across and rotates incredibly fast, completing a spin in just 10.7 minutes. Great place to live if you like sunrises and sunsets. Onward!>>