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Surprising Science

Forget The 25-Foot Asteroid…How About A 3-Foot “Minimoon”?

Capturing a smaller space object that temporarily enters Earth’s orbit could be a lot easier and cheaper while still providing valuable data, say proponents.

What’s the Latest Development?

While NASA’s asteroid-retrieval mission (ARM) has its focus on grabbing a relatively large 25-foot object to pull into lunar orbit, a group of experts is suggesting that they look for something considerably smaller: tiny asteroids called “minimoons” that temporarily orbit the Earth for around a year before zooming back out into deep space. At around three feet wide, such an object would be easier to catch and bring back to Earth and it could still offer valuable scientific data. 

What’s the Big Idea?

Looking for a space object that’s smaller and closer to home has the added benefit of being cheaper, which could be a good thing considering the ongoing arguments over whether ARM is a good use of NASA funds. Researcher Bill Bottke thinks capturing a minimoon is an exciting idea that can “help achieve NASA’s human spaceflight goals, but at lower cost and reduced risk than the [other] things that are being presented today….[T]hink about [it] almost as a mini-ARM.” One caveat: So far only one minimoon has ever been spotted. However, Bottke says it’s likely that many more exist.

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