Graffiti often pops up at unexpected heights and locations, but tagging asteroids may prove useful in deflecting them from Earth, an aerospace researcher contends.
Dr. David Hyland, of Texas A&M University, has suggested shooting paint powder with an electrical charge through a tribocharging gun from a satellite—essentially, spray painting the asteroid.
It's a timely theory, as NASA is predicting an asteroid in Earth's neighborhood this week..
"The coat of paint would be very thin, almost like a Saran Wrap layer," Hyland told Wired magazine. "If we push in the right direction, we can get the asteroid to cease crossing Earth's orbit and completely eliminate the threat."
Hyland leads a team that has been studying this method for years, and he's not the only one to have profferred a paint solution to the asteroid problem.
From the Smithsonian Scientific Series (1929), taken by the U.S. Army Air Service
Between 20,000 and 50,000 years ago, a small asteroid about 80 feet in diameter impacted the Earth and formed a crater in Arizona. The 2012 DA14 asteroid that is expected to pass close to Earth on Feb. 15 is estimated at 150 feet in diameter.
The Yarkovsky Effect
The tribocharging method forces particles through a narrow tube where they rub against the walls, picking up extra electrons, and becoming negatively charged.
The solar wind in the solar system should give the asteroid a small positive charge, and once the sun bathes the asteroid in ultraviolet light, the paint particles would melt together and cover the asteroid.
It may seem advanced, but the entire process relies on a concept developed well over 110 years ago—the so-called Yarkovsky effect.
Named for Russian engineer Ivan Yarkovsky, the Yarkovsky effect suggests that by heating an object rotating in space, a small force could be exerted on the object.
As an asteroid heats up from the sun, the surface being warmed will move to face space. Escaping radiation generates a tiny rocket thrust, slightly slowing the asteroid down and minutely changing its direction. The process is slow, but this tiny push adds up over years, and eventually can change an asteroid's orbit significantly.
If an asteroid is made to be lighter or darker, it will absorb a different amount of radiation, thus increasing or decreasing this tiny thrust.
Hyland and his team are hoping to get funding for a 2021 mission to test their spray paint method on asteroid Apophis. He is currently working toward launching hardware tests in 2014 or 2015 on the International Space Station or in low-Earth orbit.
Jay Melosh, a geologist from Purdue University, and co-author of a 2010 study called "Defending Planet Earth," said that while asteroids should be positively charged, scientists don't actually know the electric field in that close of a vicinity to the asteroid.
Melosh's study reportedly favored methods involving nuclear warheads and giant impactors over techniques with slower results.
Former astronaut and co-founder of the B612 Foundation, Rusty Schweickart, says the spray painting method would probably only work for a few specific asteroids, such as Apophis.
"The problem is that Apophis is not that typical and what you'll need you'll need for most deflections is a precise orbital change. A gravity tractor that pulls an asteroid into a specific orbit would be more useful for the majority of cases," said Schweickart.
Hyland knows that his method won't be perfect for everything. "This is not going to be the sole method of asteroid deflection," he said. "And I think we need as many tools in our box as we can get."
NASA / JPL-Caltech
The 2012 DA14 asteroid will be the closest an asteroid of this size has been known to pass by Earth.
Last year, Sung Wook Paek, a graduate student in MIT's Department of Aeronautics and Astronautics, also suggested using the Yarkovsky effect to deflect asteroids. His novel method involved launching rounds of paint powder-filled pellets.
If timed just right, and launched from a spacecraft at a close distance, the paintballs would cover the front and back of the asteroid, doubling its reflectivity.
However, the paintballs would have to be tough enough to not explosively decompress, yet weak enough to splatter on the asteroid's surface, Hyland said.
Near Earth Objects
According to NASA's Near Earth Object Program, the 2012 DA14 asteroid will pass very close to Earth on Friday (Feb. 15) at about 2:24 p.m. ET. In fact, it will pass so close that it will be inside the ring of weather and communications satellites.
At its closest distance, the asteroid will be about 1/13th of the distance to the Moon.
The NASA program can accurately predict the asteroid's path, and NASA said that, "... it is therefore known that there is no chance that the asteroid might be on collision course with the Earth."
Astronomers estimate that the asteroid is about 150 feet, or 45 meters, across.
The close approach is a record for a known object of this size. An actual collision by an object of this size is expected about once every 1200 years, according to the NEO Program.
"There are lots of asteroids that we're watching that we haven't yet ruled out an Earth impact, but all of them have an impact probability that is very, very low," said Don Yeomans, manager of the NEO Program, at a press briefing.