Thursday marks 30 years since the space shuttle Challenger lifted off on a cold Florida morning and passed into history when the ship carrying seven astronauts – one the first “civilian” in space — exploded some 73 seconds into its flight.
Below is a look back at what happened three decades ago and the events that lead to the destruction of Challenger.
What happened that day: The Challenger, officially STS-51L, was readied for launch on the morning of Jan. 28, 1986. The launch had been delayed several times, and NASA officials were anxious to get Challenger into space to meet a schedule of 16 planned missions for 1986. With all systems registering “go,” the countdown began and the shuttle blasted off at 11:38 a.m.
The shuttle cleared the launch pad and headed into a brilliant blue Florida sky, performing perfectly, or so everyone thought. Seventy-three seconds into the flight, witnesses began to see a flame move up the side of the external fuel tank, then what looked like an explosion as the tank collapsed, and its contents — the fuel propellants — mixed and ignited. The tank was ripped away from the body of the shuttle and it spun wildly out of the sky.
At first, Johnson Space Center officials in Houston were not aware of what happened and continued the routine of relaying trajectory and speed information. Seconds later it was clear what everyone had seen was not what was supposed to happen, and NASA commentator Steve Nesbitt alerted those listening to the tragedy when he said, “Flight controllers here are looking very carefully at the situation. Obviously a major malfunction.”
The fall back to Earth: The shuttle was 46,000 feet in the air when the accident happened, traveling at twice the speed of sound. The craft continued its upward trajectory, reaching 65,000 feet about 25 seconds later. The shuttle, having lost the other two fuel tanks, was at the mercy of physics and was quickly torn apart by aerodynamic forces. Challenger, now in pieces, began its fall back to Earth, hitting the Atlantic Ocean at 207 mph some two minutes and 45 seconds after the breakup.
The shuttle pieces struck the ocean surface at 200 times the force gravity, ”far in excess of the structural limits of the crew compartment or crew survivability levels,” a NASA report later read.
What caused it: The official report concluded that a leak in the solid rocket booster joint allowed superheated gas to escape and burn through the external tank, causing the collapse of the tank. Many blamed the cold weather in Florida that day for the problem, saying the rings that helped seal the tank joints were not made to be used in weather so cold. The official report of the accident lists weather only as a contributing factor.
The rings – called O-rings – meant to seal the segments of the booster had failed to do their job in the right-side solid rocket booster. That is where the superheated gas leaked through and burned the side of the rocket, starting the chain reaction that would bring the shuttle down.
Why didn’t they know about it: Engineers at the company that made the O-rings, Morton Thiokol, said they tried to warn their bosses the night before the launch that they seals could be brittle because of the cold and needed to be replace, but they said they were overruled and told the launch would go on as scheduled.
Who we lost: The team on Challenger was different than any that had come before it. A “civilian” was to fly with the crew. Christa McAuliffe, a New Hampshire high school teacher, had been chosen to go into space and teach lessons from the shuttle. She, Hughes Aircraft Co. satellite engineer Gregory Jarvis and physicist Ronald McNair were on the lower deck of the crew cabin at lift-off. On the upper deck were engineers Judith Resnik and Ellison Onizuka, the shuttle’s pilot Michael Smith and the ship’s commander, Dick Scobee. It was the first flight for Jarvis and Smith, the rest of the crew, save McAuliffe, had all flown on shuttle missions before.