Editorials

'A piece of history of the solar system'

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.

Those samples will be compared with the others from the surface. The differences between the two may prove as valuable as the insights gained from examining the excavated samples. Scientists hope to gain a better understanding of the conditions under which rocks like 162173 Ryugu were formed.

Hayabusa2 will remain near the asteroid until the end of this year and return to Earth toward the end of 2020. The entire journey is expected to total more than 5 billion km. Given that distance, the ability of mission scientists to not only land the probe on the asteroid but to do so repeatedly, and to put the final landing within a small 3-meter area defined by the previous encounter — to collect the pristine material, Hayabusa2 had to touch down inside the crater created by the April shot — was extraordinary.

Japan needed this win. The first Hayabusa probe is officially classified as a “success” by the Japan Aerospace Exploration Agency, but it suffered various problems, including power outages, losses of communication, and the failure of its miniprobe. Some problems were the result of bad luck: The mission occurred during the largest solar flare in history, which damaged the probe’s engines. Some problems were engineering failures, however.

As a country, Japan must decide the priority it attaches to space exploration. Satellites are essential to the communications networks that provide the sinews of a modern society, and correspondingly, outer space is assuming greater importance as a domain for national security.

But Japan, like many other nations, has an interest in understanding and, if possible, exploiting opportunities still further from Earth. China just landed the first probe ever on the dark side of the moon and will send another mission to the moon to bring back lunar samples. The United States continues to land probes on Mars — and remains the only country to do so.

Indeed, space exploration is increasingly a contest between those two countries. Each spends as much as $40 billion on space (when military expenditures are included in the totals), sums that dwarf those of other countries. Japan, for example, earmarks an estimated ¥300 billion on its space budget, less than a tenth of what the U.S. spends.

While the importance of near space for national security may reinforce that competition, it is far better for outer space to be viewed as the common heritage of all peoples and those governments, along with others, should work together to learn about the solar system and seize the opportunities that are created. This future is more likely if countries focus on the things they do best. For Japan, this means maximizing its expertise in unmanned space technology. Its boosters are among the most reliable in the world and the success of Hayabusa2 will confirm its place as one of the leaders in developing and returning probes.

Another important shift is taking place in thinking about space exploration: The private sector is moving into the lead. In the U.S., companies like SpaceX and Blue Origin are setting the pace. Japan has Ispace, which is developing robotic spacecraft technologies to discover, map and use the natural resources on the moon. More than 300 private companies collaborated to create Hayabusa2. Japan must ensure the probe returns safely, and then encourage cooperation among the public and private sectors so there are more successes in the future.

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