Watch The World’s Largest Rocket Send a Top Secret Spy Satellite into Orbit

On Saturday afternoon, a top secret American spy satellite called NROL-37 was launched into orbit by the most powerful rocket currently operating in the world—the Delta IV Heavy vehicle, manufactured by United Launch Alliance (ULA).

Liftoff for NROL-37. Video: YouTube/United Launch Alliance/Horizon Productions SFL

Given that NROL-37 is a highly classified mission run by the US National Reconnaissance Office (NRO), the agency that oversees America's fleet of spy satellites, few details about its specs and directives have been released. But spaceflight sleuths have gleaned a few clues from the circumstances of the launch.

For starters, the choice to use such a beefed-up rocket suggests that the payload itself is fairly sizeable. Standing nearly 22 stories high and propelled by three hulking booster cores, the Delta IV Heavy rocket is only schlepped out to the launchpad for special occasions. Since it was first introduced in 2004, the Heavy has flown just eight times, with its most recent liftoff occurring in December 2014.

The rocket can deliver payloads of 14,880 pounds to geosynchronous Earth orbit, over 22,000 miles above Earth, which is where NROL-37 is expected to park itself. This flight path has led to a consensus among space detectives that NROL-37 is part of the Orion series of spy satellites (also known as "Advanced Orion" and "Mentor"), which dates back to the 1980s.

The finer details, however, are open to speculation. The public access to the satellite's communications were promptly cut off when its payload fairing was jettisoned 6.5 minutes after liftoff from Cape Canaveral. This prescheduled radio silence is standard protocol for an NRO launch.

But despite all the mystery, one thing about the mission is abundantly clear: It has a seriously badass insignia patch. Behold, Sir NROL-37, the dark knight of American reconnaissance spaceflight.

It's not often that a spaceflight mission logo could double as a Game of Thrones character.

According to the NRO's Facebook page, "the mission patch depicts a knight, a symbol of courage with a chivalrous code of conduct representing bravery, training, and service to others."

"The knight stands in front of the US flag in a defensive posture as to protect at all cost," the post says. "The eagle on the chest is a symbol of both freedom and the United States of America. The sword is a message of tenacious, fierce focus with the claws representing extreme reach with global coverage."

Just in case you were wondering if this kind of imagery is a one-off for NRO missions, check out this mission patch for NROL-39, which launched in 2013.

More of these flamboyant design choices are catalogued in this fantastic Smithsonian feature on US spy satellite insignias.

If SpaceX's Falcon Heavy rocket meets by its target deadline of a November 2016 maiden flight, Saturday's launch may mark the Delta IV Heavy's last voyage as the world's largest and most powerful operational rocket.