The Japan Aerospace Exploration Agency’s (JAXA) Hayabusa2 probe entered orbit around asteroid 162173 Ryugu on June 27 of this year. In practice for its eventual landing on the asteroid, it descended from a height of 12.5 miles (20 km) to a distance of just 2,792 feet (851 meters) above the surface after spending 21 hours in free fall.
From a distance of just 0.6 miles (one km), Hayabusa2 trained its Optical Navigation Camera–Wide Angle on Ryugu’s surface, revealing large rocks and dust.
Mission controllers conducted the descent on August 6 for the purpose of gaining a better understanding of the asteroid’s gravity.
“By monitoring the exact movement of the Hayabusa2, we can see how strong the gravitational attraction is from Ryugu,” a JAXA statement explained.
Several images of Ryugu were taken as the spacecraft fell toward the asteroid.
Although Ryugu occasionally crosses Earth’s orbit and is classified as a potentially hazardous asteroid, it poses no threat to our planet. However, by studying its composition, scientists will likely gain valuable insight into appropriate methods of deflecting or destroying any similar asteroids that may one day pose such threats.
Studying Ryugu’s composition will also provide researchers with important information about the history of the solar system.
In 2010, JAXA’s first asteroid sample return mission, Hayabusa, successfully brought back samples of asteroid 25143 Itokawa to Earth.
The Hayabusa2 spacecraft, launched in December 2014, was built with improved ion engines, navigation technology, guidance technology, antennas, and attitude control systems. It will drop a lander and three rovers onto Ryugu’s surface and use an explosive device to obtain samples of its subsurface.
After collecting samples multiple times, Hayabusa2 will leave Ryugu in December 2019 and return home a year later.
Following its successful closeups of the asteroid, Hayabusa2 fired its thrusters and returned to an altitude of approximately 3.1 miles (five km) above its target’s surface.