NASA astronaut and former University of Hawai'i solar physicist Edward Lu is calling for a new spacecraft that would divert asteroids on a path to slam into Earth.

The small space tractor, costing between $200 million and $300 million, would hover near an asteroid to exert enough gravitational pull that the space rock's orbit would change and a collision with our planet would be averted, Lu said before a crowd packed into a 300-capacity auditorium at the University of Hawai'i-Manoa Monday night.

Lu was part of a panel that included three Hawai'i scientists who characterized the chances of an asteroid colliding with Earth as rare but deserving of the same level of attention as major earthquakes, tsunamis and hurricanes.