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Science in Mind

MIT scientist proposes asteroids as destinations before Mars

A NASA image showed a simulation of asteroid 2012 DA14 approaching in 2013.
A NASA image showed a simulation of asteroid 2012 DA14 approaching in 2013. NASA/JPL-Caltech/Associated Press

Asteroid scientist Richard Binzel is often preoccupied by questions about the rocky bodies that usually sit in a belt between Mars and Jupiter. Spray-painted styrofoam asteroids hang from the ceiling of his Massachusetts Institute of Technology laboratory — evidence of his passion for a topic that tends to capture public attention only when one passes too close for comfort.

In the journal Nature on Wednesday, however, Binzel made a surprising and strong case for thinking about asteroids not for their scientific value but as destinations for human space travel.

Millions of near-Earth asteroids are much closer than Mars. Those, Binzel argues, offer appealing destinations for trips that could test equipment and protocols as technology and systems are developed that could be capable of ferrying people farther and farther — and eventually all the way to Mars.


“It’s the destination that’s important, not the object,” Binzel said in an interview. “Certainly, some objects will be more interesting than others, but the fundamental goal is to have an interplanetary test flight.”

Binzel is critical of a current multibillion dollar NASA plan to lasso an asteroid and tow it close enough so that spacecraft and people could visit it, a feat that Binzel likens to putting an asteroid in a baggie.

Such a stunt would, he argues, neglect the true power of these rocky bodies as landing spots that would be preparation for the two-year round-trip journey to Mars.

Binzel answered a few questions about his ideas. His answers are edited for length.

MIT professor of planetary sciences Richard Binzel
MIT professor of planetary sciences Richard Binzelcourtesy of L. Barry Hetherington

Q: Why do you disagree with a strategy to tow an asteroid close to Earth and then visit it?

A: The main thing is that retrieving an asteroid is a misstep off the path to Mars. . . . Mars is too far, Mars is out of reach of our first steps. When we first start flying our new [human spaceflight] system, we’ll stay in the Earth-moon system because that is a safe place to test out your new hardware [and] that makes great sense. And when we are confident that we are ready to try for the first time to leave the cradle of the Earth-moon system, we can simply go venture out into space and come back. That would be fine, but there is also an abundance of these asteroids and that’s what is new — the realization of nearly 10 million near-Earth asteroids larger than 10 meters. . . . We have an abundance of destinations to go to when we’re ready to take our first interplanetary baby steps.


Q: What kind of asteroid should we visit?

A: The flight matters more than the object you have right outside your window. Eventually, a scientist could say which [asteroids] out of 10 million — maybe there are 50 to 100 that are more perfect [destinations]. Scientists could tell you which one they prefer, but the point is really having stepping stones for advancing toward Mars.

Q: What would you want to do once you get there?

A: I’m an asteroid scientist, but I downplay science. It is not the driver here. This is all about destinations, proving you have destinations capability. . . .

Yes, we can do experiments and explore what these asteroids are like once they’re outside our window, but the most important thing is we’re in interplanetary space.


Q: To identify asteroid destinations, you point out we would need to do a survey of nearby asteroids. Does this have implications for understanding hazardous asteroids that could strike Earth?

A: A survey should be of great interest to the human exploration side of NASA, because a survey will deliver thousands of destinations and sooner or later those destinations are going to come into play for human spaceflight. So isn’t it interesting that the survey that will deliver human exploration destinations will, at the same time, address the long overdue assessment of impact hazards? So they converge. It’s a win-win.

What I’m trying to insert that’s new here is the survey is of enormous value to human exploration — that adds a new element to motivate the survey.

Carolyn Y. Johnson can be reached at cjohnson@globe.com. Follow her on Twitter @carolynyjohnson.