Japan's Hayabusa2 space probe made history last week when it collected samples from beneath the surface of an asteroid. The feat was an engineering and mathematical marvel that will, if the mission is completed as planned, provide unprecedented insight into conditions in the solar system before planets were formed. It is, as one project manager exulted, like holding "a piece of history of the solar system." It is a much-needed accomplishment for Japan's space program, and a reminder of the value of investing in this effort.
The Hayabusa2 probe was launched in December 2014 and rendezvoused with asteroid 162173 Ryugu 3½ years later in June 2018. The asteroid, about 900 meters in diameter, is 300 million kilometers from Earth. (Most asteroids are further away; this one was chosen for investigation because its orbit periodically brings it closer to Earth.) The probe has been busy since it came into contact with the rock; it has not landed permanently on it but instead has periodically lowered itself to the surface and then returned to a height some distance away.
Last September, it dropped two small rovers onto the asteroid surface and a third was deployed a few months later. In February, samples were collected. In April, a projectile was fired into the asteroid to create a crater to expose its interior, rock that had been covered up since Ryugu's creation hundreds of millions, if not billions, of years ago. Last week, the probe returned to the surface and fired a second "bullet" into that crater; it then collected the debris that was dislodged.