domingo, 18 de maio de 2014
Can NASA Save Us from an Asteroid Ready to Slam into Earth?
We've seen the destruction that even a small meteorite entering the Earth's atmosphere can cause when it impacts our planet, a la the Chelyabinsk meteor that exploded over Russia in February 2013, so the implications of a much larger, scarier meteor on a collision course with Earth are even more dire. If a massive space rock were found to be hurtling towards our planet, would NASA or any of the world's space agencies be able to stop it or at least minimize the impact? NASA's ambitious asteroid lassoing mission will give us a good indication of what our capabilities are, or can be, should we find a large space rock headed in our direction.
NASA announced last year that it plans to capture a near-Earth asteroid in a stable lunar orbit that astronauts will then be able to visit for research and exploration. During this mission NASA may be able to test out Earth's defenses against space rocks.
The mission's details are still being worked out, and NASA officials have stated that different methods could be used to deflect asteroids heading to Earth. If the mission grabs a small space rock or large boulder off an asteroid's surface, a planetary defense demonstration would be involved, which would show the first test of an enhanced gravity tractor in space.
This gravity tractor technique would use a robotic probe flying next to a space rock for months, maybe even years, while a small gravitational tug slowly pushes it off its course. If the probe has a larger mass, it will have a greater gravitational pull. Taking a boulder off an asteroid that could damage Earth will help to significantly increase the mass of the deflection mission.
Lindley Johnson, program exective for NASA's Near-Earth Object (NEO) observations program said:
"We'd go into this enhanced gravity tractor position after we retrieve the boulder and demonstrate that we have even more gravity attraction capability by doing that."
Johnson added that nearly a dozen candidates have been found for the mission, with at least six for each option. The best rock to use for the boulder grabbing mission could be Itokawa, a 1,750-foot-long space rock that was visited by Japan's Hayabusa probe in 2005.
The U.S. government has set a 2025 exploration deadline to have astronauts visit the yet-to-be-selected asteroid. In 2010, President Barack Obama told NASA to land on a nearby asteroid by 2025 and on Mars by the mid 2030s.
The mission is currently in a "preformuation" phase, which means that NASA is still looking over ideas and data for the mission. NASA is hoping to have a basic concept for the mission by the end of 2014.
Publicado por Jorge M. Gonçalves às 8:26 da tarde