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As the four Artemis II astronauts looped around the moon this week before their return trip to Earth, so did four transparent chips, each about the size of a USB thumb drive and seeded with their bone marrow cells. Each chip is an “avatar” — an attempt to model key aspects of the biology of Victor Glover, Jeremy Hansen, Christina Koch and Reid Wiseman, the four humans whose courage and wonder have captivated the world. (Johnson, 4/9)

The Artemis astronauts’ reflections echo a long described change that occurs when humans are given the chance to view Earth from space. (Wattles, 4/8)

Research suggests that rocket exhaust and debris could be threatening the ozone layer, though many uncertainties persist. (Skibba, 4/6)

New research is upending what we thought about the consciousness of patients, leaving families with agonizing choices. (Engelhart, 4/9)

Matthew Shifrin loved building Lego sets as a child. But since he's blind, he relied on others for help. (Casey, 4/6)

Plastic ice rinks almost certainly generate microplastics because they are made of polyethylene and exposed to constant friction from skates — but there has been little rigorous study of how much is produced, said Sanjay Mohanty, an associate professor of environmental engineering at the University of California, Los Angeles. “Even seemingly small amounts, like a couple of grams of plastic shavings per square meter per month, translate into millions of particles,” he said. (Belson and Tabuchi, 4/5)

In places like Indonesia, plastic refuse is often burned in unregulated low-tech furnaces that pose grave health risks. (Gardiner, 4/10)