The water was murky, swirling from surface winds, keeping divers Terry Bailey and Mike McAllister from seeing more than an arm’s reach in front of them. They had been diving for days, recovering Challenger’s debris, and, now, on this dive, they had only six minutes left in their tanks.

They were about 100 feet down, moving across the seafloor, when they almost bumped into what at first appeared to be a tangle of wire and metal. Nothing that unusual, nothing they hadn’t seen on many dives before.

Then, they saw it. A spacesuit, full of air, legs floating toward the surface. There’s someone in it, Terry Bailey thought.

No, that’s not right, he admonished himself. Shuttle astronauts do not wear pressurized spacesuits during powered flight. They wear jumpsuits. They carry along two pressure suits if they should be needed for a repair spacewalk.

He turned to his partner, Mike McAllister. They just looked at each other and thought, “Jackpot.” This is what we’ve been looking for. The crew cabin.

Low on air, the two divers made a quick inspection, marked the location with a buoy and returned to their boat to report the find.

A cabin intact

Early the next morning, the USS Preserver recovery ship put to sea. The divers began their grim task of recovering the slashed and twisted remains of Challenger’s crew cabin and the remains of its seven occupants.

On first inspection, it was obvious that the shuttle Challenger’s crew vessel had survived the explosion during ascent. A 2-year-long investigation into how the crew cabin, and possibly its occupants, had survived was begun.

Veteran astronauts Robert Crippen and Bob Overmyer, along with other top experts, sifted through every bit of tracking data. They studied all the crew cabin’s systems — even the smallest, most insignificant piece of wreckage. They learned that at the instant of ignition of the main fuel tank, when a sheet of flame swept up past the window of pilot Mike Smith, there could be no question Smith knew — even in that single moment — that disaster had engulfed them. Something awful, something that had never before happened to a shuttle, was upon them like a great beast.

Mike Smith uttered his final words for history, preserved on a crew cabin recorder.

“Uh-oh!”

An ultimate epitaph.

Immediately after, all communications between the shuttle and the ground were lost. At first, many people watching the blast, and others in mission control, believed the astronauts had died instantly — a blessing in its own right.

But they were wrong.

NASA’s intensive, meticulous studies of every facet of that explosion, comparing what happened to other blowups of aircraft and spacecraft, and the knowledge of the forces of the blast and the excellent shape and construction of the crew cabin, finally led some investigators to a mind-numbing conclusion.

They were alive all the way down.

Rise and fall

The explosive release of fuel that dismembered the wings and other parts of the shuttle were not that great to cause immediate death, or even serious injury to the crew. Challenger was designed to withstand a wing-loading force of 3 G’s (three times gravity), with another 1.5 G safety factor built in. When the external tank exploded and separated the two solid boosters, rapid-fire events, so swift they all seemed of the same instant, took place. In a moment, all fuel was gone from the big tank.

The computers still functioned and, right on design plan, dutifully noted the lack of fuel and shut down the engines. It was a supreme exercise in futility, because by then Challenger was no longer a spacecraft.

One solid booster broke free, its huge flame a cutting torch across Challenger, separating a wing. Enormous G-loads snapped free the other wing. Challenger came apart — but the crew cabin remained essentially intact, able to sustain its occupants.

The explosive force sheared metal assemblies, but was almost precisely the force needed to separate the still-intact crew compartment from the expanding cloud of flaming debris and smoke. What the best data tell the experts is that the Challenger broke up 48,000 feet above the Atlantic. The undamaged crew compartment, impelled by the speed already achieved, soared to a peak altitude of 65,000 feet before beginning its curve earthward.

The crew cabin, reinforced aluminum, stayed solid, riding its own velocity in a great curving ballistic arc, reached the top of its curve, and then began the dive toward the ocean.

It was only when the compartment smashed, like a speeding bullet, into the sea’s surface, drilling a hollow from the surface down to the ocean floor, that it crumpled into a tangled mass.

Mercifully unconscious?

But even if the crew cabin had survived intact, wouldn’t the violent pitching and yawing of the cabin as it descended toward the ocean created G-forces so strong as to render the astronauts unconscious?

That may have once been believed. But that was before the investigation turned up the key piece of evidence that led to the inescapable conclusion that they were alive: On the trip down, the commander and pilot’s reserved oxygen packs had been turned on by astronaut Judy Resnik, seated directly behind them. Furthermore, the pictures, which showed the cabin riding its own velocity in a ballistic arc, did not support an erratic, spinning motion. And even if there were G-forces, commander Dick Scobee was an experienced test pilot, habituated to them.

The evidence led experts to conclude the seven astronauts lived. They worked frantically to save themselves through the plummeting arc that would take them 2 minutes and 45 seconds to smash into the ocean.