Hitch hike to Mars inside an asteroid

By Aussiegirl

What won't they think of next! However, I don't like the sound of this sentence from the article: Orbital changes could potentially divert it from its close approach to Mars or even put it on a future collision course with the Earth.

Hitch hike to Mars inside an asteroid - space - 23 October 2006 - New Scientist Space

Hitch hike to Mars inside an asteroid
David Shiga

Burrowing inside an asteroid whose orbit carries it past both the Earth and Mars could protect astronauts from radiation on their way to the Red Planet. The idea is being investigated with funding from NASA.

Outside the protective bubble of the Earth's magnetic field, charged particles from the Sun and from beyond our solar system in the form of cosmic rays pose a hazard to astronauts.

Long-term exposure to this space radiation could increase the risk of astronauts developing cancer and could interfere with their memory and attention skills.

Building shielding on Earth to launch with the spacecraft would add a lot of extra weight to the vehicle and would increase the cost of the mission as a result. Other ideas, like a lightweight plasma bubble that could be generated in space are being explored, but have disadvantages of their own.

Now, the NASA Institute for Advanced Concepts (NIAC) in Atlanta, Georgia, US, is funding a study to see whether asteroids could be used for radiation shielding. The study is being carried out by Daniella Della-Giustina, a student at the University of Arizona in Tucson, US.

A small population of asteroids pass by both the Earth and Mars in their orbits. So the idea is that a spacecraft containing Mars-bound astronauts could rendezvous with one of these objects as it goes by the Earth and travel with it until it nears the Red Planet.

In one version of the idea, the astronauts would actually dig a hole in the asteroid, put the spacecraft inside and cover it over with material from the asteroid. Within this protective burrow, the spacecraft would be shielded from cosmic rays during the six- to 10- month journey to Mars.

In a second version, the spacecraft would not contact the space rock. Instead, it would hover nearby, and astronauts or robots would visit it on spacewalks. "You'd have the astronaut actually go to the asteroid and begin to extract material," Della-Giustina told New Scientist.

The material collected could then be brought back and put into a hollow shell surrounding the spacecraft. The shell of rocky debris would make a radiation shield, she says.

The plan has some potential hurdles, but nothing that seems to rule it out, says Daniel Durda of the Southwest Research Institute in Boulder, Colorado, US.

He says it is unlikely that such a rendezvous would significantly alter the asteroid's orbit but that the possibility should be investigated further. Orbital changes could potentially divert it from its close approach to Mars or even put it on a future collision course with the Earth. [....]