INDIAN RIVER COUNTY — Space shuttle Endeavour’s reentry over Indian River County prompted at least 21 phone calls to 911, according to authorities, after the classic double sonic boom shook windows of many residents’ homes. The Indian River County Sheriff’s Office received 20 calls, according to spokesman Jeff Luther. Vero Beach’s 911 service took one call, spokesman Officer John Morrison said.Endeavour’s 7-member crew ended its 16-day journey of more than 6.5 million miles shortly before 11 a.m. Friday. The shuttle landed at NASA’s Kennedy Space Center in Cape Canaveral. The crew delivered the final piece of the Japan Aerospace Exploration Agency’s Kibo laboratory and a new crew member to the International Space Station.The landing path the shuttles take on re-entry varies depending on the orbit they are in, and most shuttles approach Cape Canaveral on a more west-to-east trajectory rather than coming up from the south as Endeavor did this morning.
Double sonic booms are common with the shuttle’s reentry and are caused by the supersonic flight of an aircraft. “Sonic booms generate enormous amounts of sound energy, sounding much like an explosion,” according to Wikipedia.com.
To break the sound barrier, objects must be traveling at least 761 mph — known as Mach 1 — when measured at sea level and at room temperature.