To look at the stars is to gaze at history. The images we see are millions, if not billions, of years old, an age that reflects their distance and the time that it takes for light to traverse solar systems, galaxies or the universe itself. Science now allows us to pluck pieces of that past from asteroids as they whiz by, a study that can not only tell us about that distant past but may reveal something of our own origins as well.
That search is expected to bear fruit when Japanese scientists crack open the payload from the Hayabusa2, which returned to Earth last week. The spacecraft collected samples from the asteroid Ryugu last year in two mean feats of engineering derring-do. The probe flew five years and 300 million kilometers to land on a rock 1 kilometer wide that was 800 times farther from Earth than the moon. A first landing collected surface soil. After six months of observation, a projectile was fired into the rock and a second probe scooped up a sample of subsurface material.
It is that second sample, the first subsurface asteroid sample ever collected, that has scientists most excited. They believe that this soil has not been contaminated by exposure as Ryugu traveled the solar system. They hope that it will provide insight into how our planet was formed — and perhaps explain the sources of organic materials on Earth.
The Earth and other planets emerged from the gas, ice and dust of the solar nebula some 4.6 billion years ago. The pieces that were not consumed in that process remain as asteroids. The large planets were transformed, becoming increasingly complex ecosystems; asteroids remained unchanged, small preserved samples of that original chemical brew. Those asteroids, scientists argue, offer a picture of our planet at those early stages.
Ryugu is a carbonaceous asteroid, which is thought to contain both organic materials and hydrates, minerals rich in chemically bound water. Life may have begun on Earth when other carbonaceous asteroids crashed into it and deposited the water and those organic materials. They weren’t galactic taxis, carrying life forms across solar systems. Rather, they may have generated amino acids that could trigger chemical processes that produced proteins which could lead to life itself.
Japan’s scientists will compare the Hayabusa2 samples to those collected in 2010 from the asteroid Itokawa. The United States collected a sample from the asteroid Bennu during the OSIRIS-REx mission, which is expected to return to Earth in 2023. Japan and the U.S. have agreed to swap their samples. Hopefully, scientists will also get access to the lunar rocks that China gathered during the time its Chang’e 5 spacecraft spent on the moon. It is scheduled to return to Earth this month. Those rocks are anticipated to be much younger than those collected by the Apollo astronauts during their landings on the moon decades ago and should make for intriguing comparisons.
More such missions are in the works. Japan will launch in 2024 a sample-collecting mission to Phobos, one of Mars’ moons. The U.S. has dispatched another rover to Mars itself, which will store samples for a future trip back to Earth. Scientists are especially excited about the ability to retrieve those collections; not only is there equipment on Earth to run more advanced tests, but storage on Earth allows for the possibility of tests that do not yet exist.
Hayabusa2’s work is not finished. It dropped off the samples during a pass-by of Earth and then headed off to asteroid 1998KY26, a 30- to 40-meter-diameter body that appears to rotate once every 10 minutes. Astronomers call this a “fast rotating micro-asteroid.” It will only observe that body when it arrives in July 2031.
Hayabusa2’s success is rightly trumpeted as a national triumph, especially after the mixed results of the first Hayabusa probe. The Japan Aerospace Exploration Agency (JAXA) studied that experience closely and then assembled a public-private partnership of nearly 300 companies for this mission. The lessons learned and technology developed for Hayabusa2 will be deployed in the private sector and help Japan remain competitive as space is opened up for more activity.
While all governments are alert to the possibilities and importance of a presence in space, the tendency is to see this as a national security issue, and thus a military problem. It is a sad commentary that outer space, once considered the common heritage of mankind, is more commonly viewed as another strategic outpost that can be used for national advantage.
It is a depressing but accurate reflection of our time. We should reclaim those reaches from the strategists and generals and push forward instead the scientists and dreamers who rightly see infinite and revealing possibilities when they look to the heavens, and who can find, in the farthest most distant corners of the universe, insights into our being and existence.
The Japan Times Editorial Board
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