Space & Tech
Falcon Heavy launches NROL-97 as booster returns bring sonic booms
The rocket lifted off at 11:54 p.m. Thursday from Kennedy Space Center. Two boosters returned to the Cape; NASA’s research explains the sound that follows supersonic flight.
SpaceX’s Falcon Heavy lifted off from Kennedy Space Center at 11:54 p.m. EDT Thursday, October 1, carrying the classified NROL-97 mission for the National Reconnaissance Office. Spaceflight Now’s updated launch report confirms that both side boosters returned to Landing Zones 1 and 2 at Cape Canaveral Space Force Station, producing sonic booms.
The flight was the first Falcon Heavy mission for the U.S. reconnaissance-satellite agency, according to Spaceflight Now. Falcon Heavy combines three first-stage boosters with an upper stage. On this mission, the two side boosters returned while the center core was expended.
Those booster landings explain the later booms associated with the flight. The sound is connected to shock waves from supersonic motion, rather than simply being another burst of launch-engine noise. NASA’s research explains that pressure waves form as a vehicle moves faster than sound and travel outward toward the ground.
A sonic boom is often described as the instant something breaks the sound barrier. NASA says that picture is incomplete: shock waves continue to form during supersonic flight. A person hears the sharp pressure change when those waves reach their location, and the vehicle can already be far from the place where the sound originated.
The sound heard on the ground also depends on the vehicle’s shape, flight path and atmospheric conditions. NASA describes how waves can merge as they travel, so nearby listeners may hear different combinations of sharp booms or rumbling. Its explanation comes from aircraft research and does not establish a measured noise level or a town-by-town footprint for Thursday’s rocket flight.
The launch time can appear under two calendar dates: 11:54 p.m. on October 1 in Eastern Daylight Time is 03:54 UTC on October 2. These describe the same liftoff. The reported launch and booster recovery do not establish details of the classified spacecraft’s operation; the public launch account provides little information about the payload.