12,000 satellites is a lot to keep track of

NASA and SpaceX have signed a special information-sharing agreement to ensure Stalink satellites do not collide with other objects floating around Earth’s orbit. 
The 13-page agreement takes the standard Conjunction Assessment (CA) process and allows deeper cooperation between the National Aeronautics and Space Administration and SpaceX. It’s a non-reimbursable agreement, meaning that it’s designed to be mutually beneficial and not for-profit. 
The agreement is structured around NASA maintaining its planned trajectory with Starlink satellites set to automatically maneuver around NASA objects. In rare instances in which Starlink cannot maneuver, then NASA will do what it can to avoid collision. 
“The veracity and timeliness of the communications between both parties is critical to maintain safe on-orbit operations,” as stated in the agreement. 
Because Elon Musk plans on sending 12,000 satellites into space to create this massive low-Earth orbit (LEO) satellite constellation, ensuring various trajectories don’t cross paths will be critical towards its survival. At the moment, SpaceX has sent 1,325 Starlink satellites into orbit. 
NASA will also provide technical support to Starlink, especially in regards to limiting photometric brightness, which is the reflectivity of a flat or uniform surface. 
SpaceX must inform NASA if Starlink satellites are within five kilometers below or above the International Space Station, or ISS. This, of course, is to prevent collision with the ISS, which would be dangerous as humans could be on board.
NASA is placing much burden on SpaceX to ensure collisions do not occur. And considering every single LEO satellite constellation company has gone bankrupt, safety and profitability is on the forefront of Elon Musk’s mind. 
At the moment, Starlink only gives acceptable coverage to those in upper latitudes in North America, specifically between 44 and 52 degrees north, which includes all of the states of Washington, Montana and North Dakota, most of South Dakota and Minnesota, and large parts of Canada. But Starlink is hoping to cover most of the world by the end of 2021. SpaceX expects completion of the Starlink internet constellation by sometime next year.