Space debris tracking. LeoLabs announced that they plan to build four additional radar installations for tracking space debris. Their current installations can track objects down to about a 10 cm diameter, but with their new installations they’ll theoretically be able to track objects as small as 2 cm. In general, current radar systems tend to be limited on the lower end to objects in the 5-10 cm range. Systems like LeoLabs’ and the US Air Force’s upcoming Marshall Islands-based Space Fence will improve coverage, but still won’t see the 128 million objects from 1 mm to 1 cm. For perspective, a collision with a 10 cm object will likely completely destroy a satellite, a 1 cm object will likely disable it, and a 1 mm object may disable a subsystem. At closing velocities around 10 km/s, the kinetic energy of even an untrackable chip of paint is greater than the destructive power of an equivalent mass of stationary TNT. Whipple shields around the ISS’s crewed areas are built to absorb impacts with objects of up to around 1 cm. For anything bigger, an avoidance maneuver is used (if we see it coming). This very detailed article about Space Fence also examines the variety of space situational awareness systems currently deployed worldwide.