High-power lasers control tiny satellites

17 Jun 2002

Laser ablation will provide an inexpensive way to put small satellites into orbit and keep them on the right course.

Photonics Associates, of Santa Fe, New Mexico, US has just started the second phase of developing a prototype laser plasma thruster for micro- and nano-satellites, which have masses of between 1 and 100 kg. Earlier this year the US Air Force Office of Scientific Research gave Photonics Associates a USD 400,000 grant to support this research.

Tiny satellites require small bursts of power but the behavior of conventional thrusters at small scales cannot be predicted from their behavior at larger scales. Photonics Associates' micro-laser plasma thruster works by laser ablation, in which an intense laser beam causes one or many atomic layers to be ejected from a condensed-phase surface. In a weightless environment the momentum rate of the ejected mass is enough to propel a small object forwards or change its trajectory. The laser beam is focused to a small point with a lens and produces sparks in precise bursts.

The Photonics Associates team, led by Claude Phipps, uses a 935 nm high-brightness semiconductor or glass fiber driven by a simple, low-voltage semiconductor switch.

The laser plasma thruster could have a total mass of just a few ounces. The anticipated lifetime output of the prototype that is currently being developed is about 500 newton seconds. This is sufficient to re-enter a 5 kg satellite in low Earth orbit. Phipps estimated that laser space propulsion could make the cost of putting satellites into low-energy orbit (currently about USD 15,000) one hundred times cheaper.

This phase is anticipated to take about two years. Following that the company plans to attract venture-capital funding to commercialize the product. Photonics Associates works with the New Mexico Engineering Research Institute, at the University of New Mexico, in this research.