Salute from Hayabusa-2

    A little more than a month ago, the Japanese Hayabusa-2 device fired its most spectacular shot at Ryugu asteroid. The probe dropped an impactor with explosives (in simple terms, a bomb) and a special camera to look at the explosion from the side, and he hid behind an asteroid. The operation was successful - the camera filmed an explosion, and recently Hayabusa-2 dropped to the impact area and found a fresh crater there.

    Photo 2 (left) and 25 seconds after the explosion


    The protagonists are the Small carry-on impactor (SCI) and the detachable DCAM3 camera.

    SCI, hereinafter JAXA

    SCI images are a small projectile or, rather, a bomb. With a diameter of 30 cm, it weighs 14 kg and carries 9.5 kg of explosive in the form of a funnel, which gives a directional explosion. A 2 mm copper sheet is installed in the lower part, which during the explosion became the main force forming the crater.

    Explosives inside SCI

    The calculated shape of a copper sheet in the first 500 microseconds after a DCAM3 explosion

    DCAM3 is a detachable module, and not with one, but with two cameras, analog and digital. Analog transmits a signal in worse quality, but in real time, digital provides better picture quality, but with a delay. Each camera has its own equipment for processing and transmitting data.

    "Hayabusa-2" went on the trajectory of decline, dropped the impactor, stepped aside, dropped the camera and went beyond the horizon of the asteroid, just in case.

    Scheme of movement

    The target for bombing was the S01 area near the equator and just west of the Kolobok crater. Criteria for selection - the estimated miss to 200 meters does not allow working in high latitudes (risk to miss), the area must be flat so that the crater is visible, and the probe can land.


    On April 5, the Hayabusa-2 onboard camera captured the last flight of the impactor. To the asteroid about 500 meters, time is greatly accelerated.

    185 seconds before the explosion. See the gopher SCI in the photo on the left? And he is there!

    In the very first photo at the top is an image from an analog camera. Digital quality will be better. 3 seconds after the explosion.

    And on April 25, the probe dropped to 1.7 km to find traces of the explosion. In the photo before and after the crater is clearly visible.

    The diameter of the crater was estimated at 20 meters, ahead of its study. For example, based on data on changes in the surface temperature of the asteroid depending on the local day that the TIR-S infrared camera collects, it will be possible to draw conclusions about how porous the crater material is.

    The Earth made the first “bombardment” of the asteroid in 2005 - the Deep Impact probe dropped the impactor onto Tempel Comet 1. Then the collision looked more beautiful - because of the relative speed of 10.6 km / s, the explosion energy was five tons of TNT.

    The impact results of the Impact impactor Deep Impact, NASA photo

    But the possibilities for studying the results were much less - the device was at intersecting courses and, after making a series of shots, flew away. Hayabusa-2 was the first probe to bomb an asteroid from its orbit. According to current plans, he will work with the asteroid until December 2019 and will go to Earth with collected samples, which will be delivered in December 2020.

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