Soyuz 5's flaming return

Flight Journal, Jun 2002 by Oberg, James

Cosmonaut survived a reversed reentry

Fliers love to tell their stories of overcoming hazards, and the more dangerous and unusual, the better. But for Russian cosmonaut Boris Volynov, his brush with a fiery death on a space flight 33 years ago was such a state secret that it was made public only recently. As his Soyuz landing capsule plunged wrong-way-forward into the flames of reentry and smoke filled the cabin, he and everyone at mission control in Moscow assumed that he was about to die. But when he didn't, the next order of business was to pretend that it had never happened, and Volynov was ordered not to tell the story. The ferocious energy required for a rocket to climb into space is obvious in the flames and roar of a liftoff. Clawing against gravity's embrace, the rocket expels tons of mass by burning it and pushing the hot exhaust toward the ground. The thunderous tail of flame is an unforgettable image of space flight. The result is that 95 percent of the rocket's original weight winds up as smoke, while the other five percent is thrust upward, and, when sideways above the atmosphere, it is moving fast enough to "fall over" Earth's horizon. The payload is then "in orbit," safely in space, and its continued tremendous velocity is the key to remaining there.

The reverse process-returning to earth-is just as fiery and fierce, but usually not as well publicized or as widely witnessed. We know that, using small rockets, the spacecraft slows down maybe by two percent of its speed, and then enters the atmosphere. Air drag slows it the rest of the way, but at Mach 25.0, it encounters tremendous temperatures from the supercompressed shock wave in front of it. The temperatures are as high as those on the sun, and the air molecules are torn into ions.

These temperatures would incinerate a spacecraft in the same way as meteors flare in their descent through the sky. But by aiming a specially shielded portion of the vehicle forward into the flames, space fliers have been able to survive reentry and the process by which the tremendous energy in their fast-moving craft bleeds off as heat.

Space travelers see an incandescent trail behind them through their overhead windows, and they might occasionally see flames where the front shock wave licks upward past their side windows. But Boris Volynov, alone among Earth's space voyagers, had a straightforward view into the flames because his spacecraft had been incorrectly aligned, and the flames washed over the less insulated, or weaker, end of his vehicle. He expected it to be the last thing he would ever see, but he could not bring himself to close his eyes.

The Soyuz spacecraft comprises three connected modules. In the center is the "descent module," in which the crew rides during launch and landing; attached to the rear of this is the "equipment module," which contains the rocket engines and power supplies for the spacecraft. At the front is the "orbital module," which contains an additional living area, radios and docking equipment for linking with other space vehicles.

In the first years of its use, the Soyuz suffered two fatal accidents. In 1967, Vladimir Komarov, a lone pilot, struggled in space with malfunctioning controls for a day until he at last managed to head back into Earth's atmosphere. During reentry, a hardware flaw caused his capsule's parachute to malfunction, and the capsule hit the ground at about 300mph. Then, in 1971, as a threeman crew returned from a pioneering space-station mission, an air valve prematurely opened while they were still in space, and they suffocated.

Boris Volynov's near disaster happened in January 1969; aboard Soyuz 5, he was returning to Earth alone after his ship had docked in space with a Soyuz 4 and transferred two of its crew to it. The "moon race" was in full swing, and this double Soyuz flight had tested the spacewalking techniques that were to be used by the cosmonauts during their moon landing, which they hoped would be ahead of America's.

The 34-year-old rookie space pilot had completed the course change back to Earth, and the Soyuz spaceship was to jettison its extra modules so that the descent module would be able to enter the atmosphere safely. Flying over the South Atlantic and heading northeast, Volynov expected to be on the ground within half an hour. But something went wrong: the equipment module failed to fully separate from the descent module. The "separation bolts" had fired, but when Volynov looked out through the window, he was horrified to see the whip antennas from that module still extending past the window. It was still attached, as Volynov confirmed by the feel of the ship as he tried to turn it manually with the hand controller that fired his orientation thrusters. "No panic," he whispered once-and then again-as recorded in interviews published decades later. He radioed his situation to a tracking ship below, and it passed on the terrifying news to mission control. It took only a few moments for them to realize that nothing could be done. The ship's heat shield was at the base of the descent module, which was now blocked by the balky equipment module. Unshielded portions of the vehicle would be exposed to the 5,000-degree Celsius heat of atmospheric reentry, and this would incinerate the capsule and its pilot.