Asteroids are big bruisers that can lead to a bad day on Earth. Dealing with space rocks that are on-target to strike our planet has prompted a number of planetary defense ideas.
At the Lawrence Livermore National Laboratory (LLNL) in California, a group of physicists, material scientists, engineers and computational researchers have focused their efforts on two principle methods of asteroid deflection – nuclear explosions and hypervelocity projectiles.
Their goal: not to destroy inbound space objects, but rather to nudge their trajectory just enough to make them miss the Earth.
“Each comet and asteroid has its own unique character, which presents a challenge for predicting how an individual target would respond to a deflection attempt,” says LLNL postdoctoral researcher, Megan Bruck Syal.
“The makeup may vary significantly from asteroid to asteroid. An individual body may have an abnormal orbit or rotation, and its size would also affect which method we might use to deflect it,” Bruck Syal notes in an LLNL press statement.
Because so little is known about asteroid strength, researchers are gathering data about how asteroid materials respond under extreme conditions.
Enter LLNL’s Jupiter Laser Facility. Come fall, specially prepared samples of meteorites will be mounted inside the target chamber of the powerful laser.
Months of preparation will come down to a nanosecond laser pulse, sending a haymaker shockwave through the samples.
The Jupiter Laser Facility (JLF) is a unique laser user facility for research in High Energy Density science. Its five diverse laser platforms offer researchers a wide range of capabilities to produce and explore states of matter under extreme conditions of high density, pressure and temperature.
The JLF includes the Titan, Janus, Callisto, Europa, and COMET lasers and associated target chamber.
The two meteorites to be used in the test — around the size of walnuts — were scavenged in Antarctica, later sorted and classified at NASA Johnson Space Center. The space rocks are to be vaporized by the high-powered laser, and the data they yield is expected to inform the prospect of asteroid deflection in the future.
Bruck Syal is teaming up with Laura Chen, a postdoctoral researcher at the University of Oxford, to help determine what sort of laser pulses to use to extract the data they need from the meteorite samples.
Space rocks aren’t like most laser targets. They tend to be much more heterogeneous, often containing chondrules, pebbly inclusions that were melted early in solar system history and embedded in a matrix of finer-grained material.
Moreover, it is this heterogeneous nature that makes it difficult to obtain the experimental data that will ultimately inform how best to deflect an incoming asteroid.
This planetary defense initiative is one of dozens of research efforts that grew out of the capabilities and expertise developed and honed in Lawrence Livermore’s weapons program.
LLNL planetary defense work is part of a confab of NASA, Los Alamos and Sandia national labs experts, along with collaborators across a number of universities and international research centers.
The challenge facing this international coalition of scientists is to detect and deflect the next large Earth-bound object.
“It’s not a matter of if, but when,” Bruck Syal adds, referring to the eventual certainty of a large celestial object impacting the Earth. “Our challenge is to figure out how to avert disaster before it happens.”