Tag: Ryugu

Ryugu from 25 miles

8:56 am

Ryugu from 25 miles

The Hayabusa-2 science team has released its first image of Ryugu, posted to the right, from a distance of only 25 miles. From the project manager:

The shape of Ryugu is now revealed. From a distance, Ryugu initially appeared round, then gradually turned into a square before becoming a beautiful shape similar to fluorite [known as the ‘firefly stone’ in Japanese]. Now, craters are visible, rocks are visible and the geographical features are seen to vary from place to place. This form of Ryugu is scientifically surprising and also poses a few engineering challenges.

First of all, the rotation axis of the asteroid is perpendicular to the orbit. This fact increases the degrees of freedom for landing and the rover decent operations. On the other hand, there is a peak in the vicinity of the equator and a number of large craters, which makes the selection of the landing points both interesting and difficult. Globally, the asteroid also has a shape like fluorite (or maybe an abacus bead?). This means we expect the direction of the gravitational force on the wide areas of the asteroid surface to not point directly down. We therefore need a detailed investigation of these properties to formulate our future operation plans.

They are going to have to spend some time in orbit to figure out not only where to land, but how to do it. More information on the mission can be found here.

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Ryugu seen from 150-200 miles

8:41 am

Ryugu from 150 milesl

Cool image time! Hayabusa-2’s approach to asteroid Ryugu continues. The image to the right, cropped to post here, shows one of four images taken by the spacecraft on June 17 and June 18. In this image the distance is about 150 miles. As noted in the Hayabusa-2 press release,

The shape of the asteroid looks like a spinning top (called a “Coma” in Japanese), with the equatorial part wider than the poles. This form is seen in many small asteroids that are rotating at high speed. Observed by radar from the ground, asteroid Bennu (the destination of the US mission, OSIRIS-REx), asteroid Didymous (the target of the US DART project), and asteroid 2008 EV5 that is approaching the Earth, all have a similar shape.

On the surface of asteroid Ryugu, you can see a number of crater-like round recessed landforms. In the first image, one large example can be seen with a diameter exceeding 200m. This moves to the left and darkens as the asteroid rotates and the lower part becomes cast in shadows.

The bulge at the equator forms a ridge around the asteroid like a mountain range. Outside this, the surface topology appears very ridge-shaped and rock-like bulges are also seen. These details should become clearer as the resolution increases in the future.

Based on the visible landforms, they presently estimate Ryugu’s rotation period to be about 7.5 hours.

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Hayabusa-2 takes first photos of target asteroid Ryugu

8:34 am

On June 10 Hayabusa-2 took its first photos of Ryugu, the asteroid it will reach later this month.

The Sunday photos were taken when Hayabusa2 was about 930 miles (1,500 kilometers) from Ryugu. Last week, JAXA released a few ONC-T images taken on June 6, when the probe was 1,615 miles (2,600 km) from the space rock.

Hayabusa2, which launched in December 2014, is scheduled to arrive at Ryugu on or around June 27. At that time, the probe will begin orbiting the asteroid at an altitude of about 12 miles (20 km), JAXA officials have said.

Hayabusa2 will then start prepping for a series of complex, up-close studies of the space rock. If all goes according to plan, over the ensuing 12 months, the spacecraft will deploy three rovers and a lander on Ryugu’s surface, gouge out a small crater using an explosives-bearing impactor, and collect samples from the newly created crater.

The spacecraft will depart Ryugu in November or December 2019, and its collected samples will come back to Earth in a special return capsule in late 2020.

The image suggests that the asteroid is “not significantly elongated.”

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