Scanning the skies for near-earth asteroids might be the best first step for getting humans to Mars. planetary scientist Richard Binzel argues that NASA should abandon the AsteroidRedirect Mission, the space agency’s plan to snag a space rock and jockey it into lunar orbit for astronauts to explore. Instead, NASA should beef up its telescope surveys to search for asteroids that come closer to home. At least one whizzes between the Earth and the moon every week, Binzel writes. Sending humans out to these nearby asteroids would save scientists the trouble of wrangling a far-outspace rock, and it would giveastronauts a smorgasbord ofdifferent stepping stones to Mars, he notes.