Ars
Technica: Conjunction assessment (CA) is the jargonistic
term for monitoring satellites and debris in orbit around Earth
and identifying likely major collisions. NASA's
Goddard
Space Flight Center began monitoring for potential
collisions in 2004, and NASA formalized a policy in 2007: All
hardware with maneuver capability in low Earth orbit (LEO) or
geosynchronous Earth orbit (GEO) must have CA performed
regularly. To do that, NASA partnered with the Department of
Defense's
US Strategic Command,
which tracks objects in Earth orbit as part of its missile
launch detection and monitoring mission. Goddard's CA system is
now heavily automated. Downloads of updated tracking data are
processed daily, with analyses of future paths run forward 7
days for LEO and 10 days for GEO. The system uses Matlab to
perform two-dimensional, Monte Carlo, and nonlinear analyses to
determine collision probabilities, which are flagged for
monitoring. If a probability doesn't decrease, the system can
also calculate the necessary maneuvers to move the threatened
satellite.
