Sunday, April 7, 2019

Hayabusa 2 Tries to Create Crater on Asteroid Ryugu by Dropping Bomb

An image of separated SCI taken with the Optical Navigation Camera - Wide angle (ONC-W1) on April 5, 2019 at an onboard time of around 10:56 JST Photographed from approximately 500 meters above Ryugu Image credit: JAXA, The University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, The University of Aizu, AIST

Japan Aerospace Exploration Agency (JAXA) scientists sent a signal to the Hayabusa 2 space probe on April 5 cueing it to drop a bomb over the asteroid Ryugu to blast a crater into it. JAXA officials said Hayabusa 2 then descended to about 500 meters above the asteroid, where it released the explosive device.

"Japan Aerospace Exploration Agency has carried out operations to separate the SCI (Small Carry-on Impactor) onboard the asteroid explorer Hayabusa 2 for deployment to the asteroid Ryugu. The SCI separation has been confirmed using Hayabusa 2’s Optical Navigation Camera-Wide (ONC-W1), it is our assessment that separation of the SCI went as planned," JAXA said.

The probe's impactor device is programmed to descend for about 40 minutes after getting the signal to a height of about 200 meters and then detonating, sending an approximately 2-kg copper mass into Ryugu's surface at a speed of 2 kilometers per second.

JAXA project manager Yuichi Tsuda said the camera that separated from the probe captured the explosion and the photo showed material blown up from the Ryugu surface, indicating the mass had hit its mark.

It would be a world first if the JAXA probe succeeded in creating the crater. Plans call for Hayabusa 2 to briefly land on the asteroid sometime after late May to collect rock and sand samples from the crater.

The candidate site for the crater is near the asteroid's equator and the impact of the copper mass is supposed to create a hole several meters in diameter.

To avoid being damaged by the force of the explosion, Hayabusa 2 was programmed to move to the other side of the asteroid after it releases the bomb.

This could prove tricky since the probe will have to move at its maximum speed of 3 meters per second. Since reaching Ryugu in June 2018, Hayabusa 2 has not moved at a speed of more than 1 meter a second.

The maneuver to avoid the explosive impact is to be conducted while the space probe is, in effect, blindfolded, since its sensors to confirm position and direction will not be used.

Despite the challenges, Hayabusa 2 appeared to be operating normally after the scheduled time for the bomb to go off had passed.

Because the impact of the copper mass could send up floating debris from Ryugu that could smack into the space probe, Hayabusa 2 will ascend to an altitude of about 20 km over a two-week period. Subsequently, it will again descend to check the area around the crater.

If the probe finds no obstacles to landing on the asteroid, it will attempt to touch down on it after late May.

Hayabusa 2 made a short landing on Ryugu on Feb. 22 to fire a bullet into its surface and collect samples from the asteroid.


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