A Japanese spacecraft about 186 million miles from Earth dropped a can of explosives on an asteroid last night, excavating a crater on the rough surface. Eventually, the spacecraft will inspect the new crater, and it may even grab a sample from it, helping scientists learn more about the asteroid’s interior.
The prospecting vehicle is Hayabusa2, a spacecraft operated by the Japan Aerospace Exploration Agency. Launched in 2014, Hayabusa2 traveled to a near-Earth asteroid named Ryugu, and it has been hanging out around the object since last year. The spacecraft’s mission is straightforward: grab samples of material from Ryugu, and bring them back to Earth for further study. But the spacecraft is using a few unique methods to reach its goal, and it has dropped some robots on the asteroid along the way.
In September, Ryugu’s first big maneuver entailed deploying a pair of cylindrical robotic rovers on the asteroid that bounced around the rock’s surface to collect data and images of Ryugu. A couple of weeks later, it dropped a robotic box on Ryugu, which also studied the asteroid’s terrain. Finally, in February, Hayabusa2 got what it came for: it slowly lowered itself toward the asteroid’s surface and shot the rock with a bullet-like projectile, sending materials shooting up inside the vehicle’s collector.
Last night, Hayabusa2 was tasked with striking the asteroid with a little more force. After slowly lowering itself toward the surface of Ryugu again, Hayabusa2 sent a cone-shaped canister filled with little explosives toward the surface and then moved to a safe distance away to avoid debris. The device, called the Small Carry-on Impactor (SCI), deployed from the spacecraft right on schedule, and Hayabusa2 even snapped a picture of it moving toward the asteroid.
[SCI] This is an image taken with the wide angle optical navigation camera (ONC-W1) immediately after (few seconds) the separation of the SCI. The retroreflective sheet on the SCI glows white due the image being shot with a flash. This showed the separation was on schedule. pic.twitter.com/8FPWY470nI— HAYABUSA2@JAXA (@haya2e_jaxa) April 5, 2019
SCI’s explosives then detonated above Ryugu’s surface, sending a copper plate shooting toward the asteroid at 1.2 miles per second. The size of the resulting crater will be determined by what type of material the copper plate hits. Given the right circumstances, the crater could be around 32 feet across.
Hayabusa2 caught all of the action on camera. When it was less than a mile away, the spacecraft deployed a camera to capture the explosion, observing the creation of the crater and the resulting debris. The images will help the Hayabusa2 team find the crater later, as the spacecraft moves back toward the target area.
[SCI] The deployable camera, DCAM3, successfully photographed the ejector from when the SCI collided with Ryugu’s surface. This is the world’s first collision experiment with an asteroid! In the future, we will examine the crater formed and how the ejector dispersed. pic.twitter.com/eLm6ztM4VX— HAYABUSA2@JAXA (@haya2e_jaxa) April 5, 2019
Sometime soon, after all of the debris has settled, Hayabusa2 will return to the region it just clobbered. The mission team will then make a decision about whether they want to grab a sample from within the crater the spacecraft created. If such an operation is deemed too dangerous, Hayabusa2 may grab a sample from another crater that already exists on the asteroid instead.
Getting a sample from inside the new crater would be ideal, though, as it would allow Hayabusa2 to collect material from within the asteroid that hasn’t been exposed to space for billions of years. The whole point of visiting Ryugu and grabbing chunks from it is to learn more about the types of materials that were around at the beginning of the Solar System. Asteroids are thought to be early remnants of our cosmic neighborhood that have remained relatively unchanged since the planets first formed 4.5 billion years ago. The materials within Ryugu are perhaps the most unchanged of all, as they haven’t been worn down or altered by the space environment.
The material within this new crater may hold some detailed secrets of what types of materials existed long ago, and that could tell us a little bit about how Earth and life on it came to be. It’s thought that asteroids may have brought crucial materials and the building blocks for life to our planet, so this crater may get us one step closer to figuring out what asteroids might have delivered to a young Earth long ago.