By ANDY FLEMING
As an asteroid roughly half as large as a
football field -- and with energy equal to a large hydrogen bomb -- readies for
a fly-by of Earth on Friday, two California scientists are unveiling their
proposal for a system that could eliminate a threat of this size in an hour.
The same system could destroy asteroids 10 times larger than the one known as
2012 DA14 in about a year, with evaporation starting at a distance as far away
as the Sun.
UC Santa Barbara physicist and Professor Philip
M. Lubin, and Gary B. Hughes, a researcher and professor from California
Polytechnic State University, San Luis Obispo, conceived DE-STAR, or Directed
Energy Solar Targeting of Asteroids and exploRation, as a realistic means of
mitigating potential threats posed to the Earth by asteroids and comets.
"We have to come to grips with discussing
these issues in a logical and rational way," said Lubin, who began work on
DE-STAR a year ago. "We need to be proactive rather than reactive in
dealing with threats. Duck and cover is not an option. We can actually do
something about it and it's credible to do something. So let's begin along this
path. Let's start small and work our way up. There is no need to break the bank
to start."
Described as a "directed energy orbital defence
system," DE-STAR is designed to harness some of the power of the Sun and
convert it into a massive phased array of laser beams that can destroy, or
evaporate, asteroids posing a potential threat to Earth. It is equally capable
of changing an asteroid's orbit -- deflecting it away from Earth, or into the
Sun -- and may also prove to be a valuable tool for assessing an asteroid's
composition, enabling lucrative, rare-element mining. And it's entirely based
on current essential technology.
"This system is not some far-out idea from
Star Trek," Hughes said. "All the components of this system pretty
much exist today. Maybe not quite at the scale that we'd need -- scaling up
would be the challenge -- but the basic elements are all there and ready to go.
We just need to put them into a larger system to be effective, and once the
system is there, it can do so many things."
The same system has a number of other uses,
including aiding in planetary exploration.
In developing the proposal, Lubin and Hughes
calculated the requirements and possibilities for DE-STAR systems of several
sizes, ranging from a desktop device to one measuring 10 kilometres, or six
miles, in diameter. Larger systems were also considered. The larger the system,
the greater its capabilities.
For instance, DE-STAR 2 -- at 100 meters in
diameter, about the size of the International Space Station -- "could
start nudging comets or asteroids out of their orbits," Hughes said. But
DE-STAR 4 -- at 10 kilometres in diameter, about 100 times the size of the ISS
-- could deliver 1.4 megatons of energy per day to its target, said Lubin,
obliterating an asteroid 500 meters across in one year.
The speed of interplanetary travel -- far beyond
what is possible with chemical propellant rockets used today -- could be
increased with this sized system, according to Lubin. It could also power
advanced ion drive systems for deep space travel, he said. Able to engage
multiple targets and missions at once, DE-STAR 4 "could simultaneously
evaporate an asteroid, determine the composition of another, and propel a
spacecraft."
Larger still, DE-STAR 6 could enable
interstellar travel by functioning as a massive, orbiting power source and
propulsion system for spacecraft. It could propel a 10-ton spacecraft at near
the speed of light, allowing interstellar exploration to become a reality
without waiting for science fiction technology such as "warp drive"
to come along, Lubin said.
"Our proposal assumes a combination of
baseline technology -- where we are today -- and where we almost certainly will
be in the future, without asking for any miracles," he explained.
"We've really tried to temper this with a realistic view of what we can
do, and we approached it from that point of view. It does require very careful
attention to a number of details, and it does require a will to do so, but it
does not require a miracle."
Recent and rapid developments in highly
efficient conversion of electrical power to light allow such a scenario now,
Lubin said, when just 20 years ago it would not have been realistic to
consider.
"These are not just back-of-the-envelope
numbers," Hughes concurred. "They are actually based on detailed
analysis, through solid calculations, justifying what is possible. And it's all
available under current theory and current technology.
"There are large asteroids and comets that
cross the Earth's orbit, and some very dangerous ones going to hit the Earth
eventually," he added. "Many have hit in the past and many will hit
in the future. We should feel compelled to do something about the risk.
Realistic solutions need to be considered, and this is definitely one of
those."
Original Source: University of California at
Santa Barbara
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