March 8, 2013
Engineers Seek To Save Earth From Asteroids
Lee Rannals for redOrbit.com - Your Universe Online
The combination of new technology, a growing interest in astronomy, and more media hype has led to an even bigger fear of "what if" scenarios for potentially hazardous asteroids. However, Iowa State engineers say they are coming up with a few ideas to help save our planet from a repeat of the asteroid-impact that led to the dinosaur annihilation.
The team believes it would take the power of a nuclear missile to break an asteroid into harmless pieces when there isn't sufficient warning to use non-nuclear defenses. He and his team have drawn up a plan for the Armageddon-day scenario.
According to the scenario, a satellite carrying a nuclear device would have to be launched into orbit with a trajectory that would intercept an incoming asteroid that is between 163- and 984-feet across. The satellite could travel for up to 30 days before reaching the asteroid, after which it would be hitting the asteroid at a speed of 6.2 miles per second, creating a large crater in the hazardous asteroid.
Just before the impact, the nuclear device would be released from the back of the satellite, creating a slight delay in detonation, allowing the satellite to create the crater the bomb would set itself off in. The team believes that this explosion from inside the crater would be enough to blast the asteroid apart.
"The overall effect of an explosion under the surface is 20 times larger than an explosion on the surface," Wie said.
The researchers say the asteroid would break up into large chunks, and less than 0.1 percent of those chunks would enter the Earth's atmosphere.
"We have all the technology,” Wie said. “We don´t need anything new. But we need to engineer, integrate and assemble these technologies. And we need practice."
John Basart, a professor emeritus of electrical and computer engineering who is volunteering his time on the research, says that if we are going to prepare for these future scenarios, then we have to get started before actually discovering the asteroid.
"It´s terribly complicated. If we learn an asteroid is going to hit in a year, we don´t have a lot of time to prepare," said Basart. "One thing we´ve learned in science over the last 50 years is how violent our universe is. Yes, we have a violent universe and it´s important for our human race to plan for this. It´s not a matter of if; it´s when."
Wie said it is time to kick start a test mission, by building an unarmed prototype satellite and launch an actual test to see if a target asteroid can be hit. As an example for success, he pointed to NASA's Deep Impact Mission in July 2005. During this mission, a NASA spacecraft crashed into a comet measuring 4.7 by 3 miles, creating a crater 82 feet deep and 328 feet wide. The purpose of this mission was to expose the comet's interior, so the flyby spacecraft would have the opportunity to snap a few photos and collect spectroscopy data.
"We have done that with a large comet, but not with a 300-meter or a 50-meter asteroid," Wie said. "Now is the time to talk about a test mission,” he said. “It is time to develop a plan and demonstrate this concept."
NASA's Deep Impact spacecraft took a series of images of comet ISON over a 36-hour period in January earlier this year. This comet is expected to be making its debut in our sky towards the end of this year, possibly becoming as bright as the moon.