The DART team applauds after receiving confirmation that their spacecraft had successfully collided with the asteroid moon Dimorphos. Credit: NASA/David C. Bowman
It was a shock for the ages. On September 26, 11 million kilometers from Earth, NASA’s DART (Double Asteroid Redirection Test) spacecraft met a spectacular end when it hurtled toward a small asteroid moon called Dimorphos. This was the first test of whether humanity can alter the orbit of a space rock, accelerating Dimorphos into its orbit.
Both Dimorphos and its parent asteroid are harmless, but NASA wanted to test whether it’s possible to deflect a dangerous space rock, should it ever head toward Earth. Researchers should know the answer relatively soon. But at the same time, DART has shed an uncomfortable light on the world’s faltering efforts at asteroid defense, particularly at locating potentially dangerous asteroids.
The risk of such an errant body crashing into Earth and causing significant loss of life is small, but not zero: Scientists estimate that relatively large space rocks collide every few centuries or millennia. An event with catastrophic consequences—even if it is very unlikely to happen—should be taken seriously. After all, the dinosaurs went extinct 66 million years ago when an asteroid blasted into what is now Mexico.
That’s why it’s time for NASA to take the next step to protect the planet from killer space rocks. The agency is to fully fund the Near-Earth Object Surveyor (NEO), a space telescope that will search for dangerous asteroids.
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As the space agency of the world’s leading space nation, NASA has ended up with the overwhelming responsibility of hunting down asteroids and saving civilization from these threats. In 1994, the US Congress directed NASA to search for any potentially threatening asteroid that was at least 1 kilometer wide. The agency completed this task in 2010. NASA-funded scientists are now using several telescopes around the world to find smaller space rocks that are at least 140 meters in diameter (Dimorphos is about 170 meters in diameter). Smaller rocks are still dangerous: they could cause regional devastation. Researchers have found nearly 30,000 so far. But with current resources and instrumentation, it will take three decades to finish the job.
The small, but non-zero, risk of a dangerous space rock appearing earlier means that this is not good enough. NASA has been slowly developing a space telescope tailored to search for near-Earth objects for many years. It had given small amounts of money to a predecessor mission before embarking on the early stages of NEO Surveyor in 2019. But earlier this year, just as scientists were preparing to finalize the mission’s design, NASA proposed to cut its budget for the current fiscal year from a projected $170 million to $40 million. This would effectively delay the telescope’s launch from 2026 to 2028, if not later.
In a rare (and welcome) moment of bipartisan agreement, Congress has indicated it will restore some of the proposed budget cuts. But that funding would go only partially, providing about $80 million or $90 million for NEO Surveyor, not enough to keep the project moving forward effectively. The longer it takes to build the telescope, the more expensive it will be in the end.
Last month, NEO Surveyor passed a preliminary design review, an important step in confirming the mission’s feasibility. By the end of this year, NASA must decide whether to commit to launching the telescope. In April, a panel of experts on US planetary science priorities gave NEO Surveyor a full recommendation to proceed. Other nations are unlikely to step up and undertake this mission. For the sake of the planet, it’s time to support the mission wholeheartedly and get it going.