Itokawa / Hayabusa

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PSI: Hayabusa2 Team Prepares for Asteroid Sample Collection

Post by bystander » Thu Oct 25, 2018 6:57 pm

Hayabusa2 Team Prepares for Asteroid Sample Collection
Planetary Science Institute | 2018 Oct 25
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. ...
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ASU: Water Found in Samples from Itokawa

Post by bystander » Wed May 01, 2019 7:20 pm

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

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
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DLR: Near-Earth Asteroid Ryugu – A Fragile Cosmic 'Rubble Pile'

Post by bystander » Fri Aug 23, 2019 4:23 pm

The Near-Earth Asteroid Ryugu – A Fragile Cosmic 'Rubble Pile'
German Aerospace Center (DLR) | 2019 Aug 22
Ryugu_MASCam14_Night2_Seq3_rgb_enh.jpg
Ryugu at night – a 'cauliflower rock' with bright minerals
Credit: MASCOT/DLR/JAXA

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
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Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
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