"International space agencies have taken particular interest in sending missions to asteroids and comets across the the solar system. Collectively these are called small bodies," says Richard Binzel, EAPS Professor of Planetary Sciences and Margaret MacVicar Faculty Fellow with an appointment in AeroAstro. Nature Astronomy recently asked him, as a senior expert in the field of planetary research specializing in asteroids, to examine the myriad exploration missions and provide insights into their goals and value. "My perspective conveys the common theme of 'Seeking the Origins of Planets and Life' as being the unifying objective for missions by Japan, Europe, and the United States."
When one envisages planetary exploration, massive Jupiter, the giant rings of Saturn or expansive panoramas from Mars often come to mind. Yet 2018 saw spacecraft from two nations arrive at some of the smallest worlds so far explored. They were continuing a parade of missions that seem to go to smaller (and in one case more distant) destinations than ever before. Motivating these missions are diverse scientific objectives that can be linked into a unifying theme: to understand our origins not only in terms of the basic chemistry enabling life but also in terms of the building process of the planets themselves. Both parts are needed to create an environment conducive to life and stable in the long term. Our own spacefaring future and planetary safety have a stake in investigating these small worlds, as they hold potential resources that could sustain future human space travel, while at the same time posing a risk (low, but inevitable over the long term) of hazardous impacts.
Missions like Hayabusa2, OSIRIS-REx and NASA's New Horizons -- motivated by the potential chemistry that these target primordial objects may contain -- are part of a growing interest in small bodies, and are only the first step in a journey to surveying the multitudes of varying asteroids and finding "the most accessible and exploitable near-Earth objects."
Story Image: The asteroid Bennu as seen by the OSIRIS-REx spacecraft. The flying saucer-like shape of Bennu is generated, in part, by its spin. (Credit: NASA Goddard Space Flight Center/University of Arizona)