But Mark Sykes, president of the Planetary Science Institute in Tucson, Arizona, and chair of NASA’s Small Bodies Assessment Group, remains a big fan of asteroids. He notes that human explorers could search for resources such as water. Scientists could seek to understand the subtle pressure of light that causes asteroids to change their spin, and could retrieve samples for dating and chemical analysis that would offer a clearer picture of Solar System material than do meteorites, which, although they are pieces of asteroids, are altered during their fall through Earth’s atmosphere.
But all this could be done more cheaply with a robotic mission, says Sykes. Without a sustained drive towards something bigger — such as a human presence on Mars — even Sykes isn’t terribly excited. “You go to an asteroid, then what?” he says. “If it’s all performance art, that’s not much of a mission.”