The US Navy this week successfully launched an unmanned plane from an aircraft carrier, marking what officials are calling "an inflection point" in the military's use of drone aircraft. The X-47B prototype drone, manufactured by Northrop Grumman, took off from aboard the USS George HW Bush Tuesday, and made two low approaches before circling back to land. The test, held off the coast of Virginia, marks the first time that the Navy has ever launched an unmanned aerial vehicle (UAV) from an aircraft carrier.

"These are exciting times for the Navy as we are truly doing something that has never been done before," Rear Admiral Mat Winter wrote in a blog post this week, "something I never imagined could be done during my 29-year naval career."

The fully autonomous X-47B was designed specifically for aircraft carrier operations. According to the navy, it can reach a height of more than 40,000 feet, and has a range of more than 2,100 nautical miles. Unlike other drones, which are controlled by remote operators, the X-47B is controlled through computer software, though human operators can intervene if necessary.

Winter notes that the X-47B is "not intended for operational use," adding that Tuesday's flight was designed to "assess the feasibility of X-47B's seamless integration into the carrier systems and environment." The next step is to successfully land the craft on a moving aircraft carrier — a far more difficult task.

"For us, the question is where do you draw line?"

Navy officials have previously said they have no intent to arm the aircraft, saying that it will instead be used to gather intelligence and conduct surveillance; but the idea of an autonomous plane one day roaming the skies hasn't sat well with some critics.

"For us, the question is where do you draw line?" Steve Goose, director of the arms division at Human Rights Watch, told the Guardian. "We're saying you need to draw the line when you have a fully autonomous system that is weaponized. We're saying you must have meaningful human control over key battlefield decisions of who lives and who dies. That should not be left up to the weapons system itself."

The US Department of Defense has issued a directive that strictly regulates the use of autonomous weapons, requiring humans to oversee their use at all times, and calling for a "rigorous" review process before deployment. Officials say it will likely be several years before any autonomous systems are deployed.