Paintballs Could Deflect An Asteroid
That’s it… Astronomers have discovered an asteroid heading right towards Earth. What can be done about it to save us? According to an MIT graduate student.We could aim some paintballs its way and deflect its course. Paintballs? Surely nothing short of a nuclear device is going to change things. Or could it? In this new scenario, the answer is simple – very simple. Just a few minor changes could deflect an incoming asteroid without using catastrophic methods.
Sung Wook Paek, a graduate student in MIT’s Department of Aeronautics and Astronautics, says if timed just right, pellets full of paint powder, launched in two rounds from a spacecraft at relatively close distance, would cover the front and back of an asteroid, more than doubling its reflectivity, or albedo. How does this change things? First off, the tiny difference of being impacted by the paint pellets would help change its course and, over time, the Sun’s photons would push it even further.
As the winner of the “2012 Move An Asteroid Technical Paper Competition”, Paek’s unconventional thinking ended up being one the most creative solutions. Science has proposed many methods of avoiding an asteroid collision – from shooting it with a projectile to towing it off course. However, Paek’s thinking is almost organic in its simplicity and builds off a solution submitted last year – deflection though a cloud of solid pellets. By adding paint to the pellets, this solution utilizes solar radiation pressure – the force exerted on objects by the Sun’s photons. Does it work? You bet it does. Researchers are already aware this pressure affects the orbits of geosynchronous satellites – so why not an asteroid?
An artist's rendering of the asteroid Apophis. Image: European Space Agency
What better way to test his theory than to use asteroid Apophis as a test subject? According to observations. the 27-gigaton rock should pass close to Earth in 2029 and 2036. Paek determined it would take about 5 tons of paint to cover the 14,800 diameter behemoth. By employing the asteroid’s natural rotation, it would take two rounds of paintballs to achieve the task – splattering the rock on both sides with about a five micrometer layer reflective paint. This reflective surface would then make use of the Sun’s photon energy to nudge it off its course.
According to his calculations, Paek thinks it would be about 20 years before the cumulative effect of the solar radiation would pull the asteroid off its Earth-bound trajectory. However, there are drawbacks to this plan. A traditional launch wouldn’t be exactly the ideal, since the violent takeoff could rupture the paintballs, but assembling them in space, such as onboard the ISS, could be a viable option. Paek also adds that the “paintballs” don’t necessary have to hold paint, either. For example, they could hold an aerosol that, when fired at an asteroid, “impart air drag on the incoming asteroid to slow it down,” Paek says. “Or you could just paint the asteroid so you can track it more easily with telescopes on Earth. So there are other uses for this method.”
Lindley Johnson, program manager for NASA’s Near Earth Objects Observation Program, says Paek’s proposal is “an innovative variation” on a method used by others to capitalize on solar radiation pressure. For example, MESSENGER, a spacecraft orbiting Mercury, is equipped with solar sails that propel the craft with solar radiation pressure, reducing the fuel needed to power it.
“It is very important that we develop and test a few deflection techniques sufficiently so that we know we have a viable ‘toolbox’ of deflection capabilities to implement when we inevitably discover an asteroid on an impact trajectory,” Johnson says.
William Ailor, principal engineer for Aerospace Corp. in El Segundo, California, adds that the potential for an asteroid collision is a long-term challenge for scientists and engineers.
“These types of analyses are really timely because this is a problem we’ll have basically forever,” Ailor says. “It’s nice that we’re getting young people thinking about it in detail, and I really applaud that.”
Original Story Source: MIT News. Submitted by Tammy Plotner for “Dave Reneke’s World of Space and Astronomy News”.
Russia May Build Rocket To Destroy Earth-Threatening Asteroids
Russia could start building a space rocket capable of destroying asteroids threatening the Earth, chief of rocket and space corporation Energia said recently.
“There are three large asteroids, including Apophis, whose orbits cross the Earth’s orbit and which could hit the Earth in the next several decades,” Vitaly Lopota told the state newspaper Rossiyskaya Gazeta.
To change the orbit of a small planet of Apophis’ size, a 70-ton rocket was needed to “tow” an asteroid away from Earth or to destroy it with a thermonuclear blast, Lopota said.
Apophis was discovered in 2004. It will approach the Earth dangerously close, at about 30,000 km, which is less than one-tenth of the Moon’s distance from Earth, in 2029.
Experts calculate impact of a collision between Apophis and the Earth will be equal to a 1,700-Megaton explosion.
Lopota said existing Russian rocket carriers with RD-171 engines could be redesigned to produce a rocket capable of destroying an asteroid. Energia was ready to build such a rocket within three to five years, he said.
Currently, RD-171 engines made by NPO Energomash have been used on Zenit-3SL missiles employed in the Russia-Ukraine-Norway-U.S. joint project Sea Launch.
“We call them Tsar Engines, which no other country possesses,” Lopota said, referring to Russian artifacts, the Tsar Cannon and Tsar Bell, which were the world’s largest in their time. Source: SpaceDaily
