  Orbital debris in low Earth orbit (LEO) are now sufficiently dense that the
use of LEO space is threatened by runaway collisional cascading. A problem
predicted more than thirty years ago, the threat from debris larger than about
1 cm demands serious attention. A promising proposed solution uses a high power
pulsed laser system on the Earth to make plasma jets on the objects, slowing
them slightly, and causing them to re-enter and burn up in the atmosphere. In
this paper, we reassess this approach in light of recent advances in low-cost,
light-weight modular design for large mirrors, calculations of laser-induced
orbit changes and in design of repetitive, multi-kilojoule lasers, that build
on inertial fusion research. These advances now suggest that laser orbital
debris removal (LODR) is the most cost-effective way to mitigate the debris
problem. No other solutions have been proposed that address the whole problem
of large and small debris. A LODR system will have multiple uses beyond debris
removal. International cooperation will be essential for building and operating
such a system.
