The launch takes place on a milestone date, marking 20 years since the STS-114 space shuttle mission took off from Kennedy Space Center Pad 39B. The launch of Discovery on the STS-114 mission on July 26, 2005, marked the return to flight for the space shuttle after the Columbia tragedy investigation.

SpaceX plans to launch 24 Starlink satellites from its Falcon 9 rocket on Saturday, which may be visible above Southern California.

The issue concerns sunlight reflecting off the satellites’ surfaces. SpaceX has attempted to reduce the brightness of the reflected light by coating the satellites in a dark material, and also by adding reflective film to redirect the sunlight away from Earth.

China’s biggest networks have deployed less than 1 percent of their planned satellites, falling far behind SpaceX for dominance in space communications.

Letting AST launch its proposed spacecraft without addressing the collision risk 'would be irresponsible' and potentially subject other satellite providers to 'unnecessary risk,' SpaceX says.

The new US missile defense system will explore alternatives to Elon Musk's SpaceX, with Amazon. com's Project Kuiper among the main contenders.