Back in February of this year, NASA announced it had selected two organizations to host the final phase of its four-year series of increasingly complicated technical demonstrations involving small Unmanned Aircraft Systems (UAS), commonly known as drones.

According to a news report, several drones were spotted last week, flying at the same time in Reno, Nev., including one from the rooftop of a casino parking garage. Similar tests have been conducted in rural areas, says the report. 

The tests will continue throughout the following months in Reno, Nev. and will start in Corpus Christi, Texas in July. 

This phase represents the most complicated demonstration of advanced UAS operating in a demanding urban environment that will have been tested to date,” said Ronald Johnson, NASA’s UTM project manager.

With these tests, NASA hopes to " the commercial drone industry understand the challenges posed by flying in an urban environment." The results of the flight demonstrations also will help inform future rules, policies and traffic management procedures for operating drones safely over populated areas.