Lasers to shift killer asteroids

A team of scientists and engineers at

(UAH) is conducting research that could one day save humanity from asteroids threatening Earth.

UAH's Laser Science and Engineering Group, headed by Dr. Richard Fork, is conducting research into characterising and deflecting asteroids that may endanger Earth.

Fork, who has more than 40 years of experience working with lasers, said someday it could be possible to locate a laser in space or on the moon to look at the properties of asteroids and perhaps alter their trajectories away from Earth. Members of his group are building a laser system ‘that is the grandfather of the laser that will push the asteroids,’ Fork said.

According to calculations made by the group, an asteroid could be characterised up to 1 AU away (1.5 x 10¹¹ m). Arecibo and other radar observatories can only detect objects up to 0.1 AU away, so in theory a laser would represent a vast improvement over radar.

Fork said the current research relates back to work he performed in the mid-1980s, when he and other researchers at AT&T Bell Laboratories developed the first femtosecond lasers. They used one of the lasers to ablate, or wear away through vaporisation, material by ultra-intense laser pulses with femtosecond time resolution.

‘The laser we are developing now is also being developed to ablate materials,’ Fork said, but the device would be a substantial distance from the target. The system includes an argon laser, a mode-locked Ti-sapphire oscillator, a regenerative Ti-sapphire amplifier, a doubled neodymium-yag pulsed laser and helium-neon line-up lasers, according to Dr. Fork.

The short-term goal of the work is to amplify femtosecond pulses to high peak power at high average power for remote sensing, using unique features associated with the high pulse intensity, Fork said. The work is funded by the US Army and involves a local company that employs several of Fork's former students. The research does not concern characterising or deflecting asteroids, but Fork sees a connection.

‘My vision is that this system is the progenitor of the laser that could characterise and deflect asteroids,’ he said.