Richard Binzel of the Massachusetts Institute of Technology announced his belief that NASA's plan to capture one of the bodies is a bad idea. The asteroid expert called the Asteroid Redirect Mission (ARM) "a multibillion-dollar stunt."
The National Research Council released a report in June 2014, outlining several means by which NASA could send a human crew to Mars, although they did not announce a preferred plan. One of the paths discussed in the study involved the capture of an asteroid, for use as a staging base for a mission to the Red Planet.
Officials at NASA have several options for a trip to Mars. Astronauts could either head straight to the planet, stop at the Moon, or rope an asteroid. The national space agency will need to make this decision prior to the January 2015 budget announcement by President Barack Obama.
"The cost and complexity of human space exploration demands that each element be measured by its value towards the ultimate goal: Mars. But NASA's stated next priority will not contribute to that aim. It will require an ancillary spacecraft deploying either a huge capture bag or a Rube Goldberg contraption resembling a giant arcade-game claw. Neither technology is useful for getting humans to Mars," Binzel wrote in a letter objecting to the proposed program.
Binzel believes a thorough study of smaller asteroids passing close to Earth wold better-suit the goal of sending human beings to the Red Planet. Every year, thousands of rocky bodies, each the size of a large truck, pass as close to the Earth as the Moon. These bodies could be exploited for resources for a trip to Mars, as well as providing records of near-Earth orbits that could, one day, effect our planet.
Space missions should carry people for greater distances, for longer periods, than before, testing systems and crews for a mission to Mars, Binzel argues. The asteroid researcher is also calling for the development of robotic spacecraft that could closely study asteroids, regardless of their shape, size, or spin.
Asteroids exist in large numbers, in a belt between the orbits of Mars and Jupiter. Once in a while, a collision between two of the bodies or the gravitational effect of the largest planet in the solar system knocks an asteroid toward Earth. One of these bodies exploded above the city of Chelyabinsk, Russia, in 2013, injuring 1,100 people.
When NASA does land humans on Mars, perhaps sometime in the 2030's, they may find a colony of people waiting for them on the surface. Private developers Mars One plans to launch space travelers to the Red Planet in 2024.
Binzel's letter was published in the journal Nature.