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The normal deployment of the Soyuz parachute system: (1) the pilot and drogue chutes deploy in turn; (2) on the drogue chute; (3) jettisoning the drogue deploys the main chute; (4) while on the main chute, two ventilation valves open; (5) the base heat-shield is jettisoned; (6) the harness of the main chute is repositioned for landing; (7) retro-rockets fire 1 meter above the ground to soften the impact; and (8) the descent module lands and the chute is jettisoned.

Three last operations of the previous graphic are shown by this collage of pictures of a Soyuz descent module landing. The final pre-landing operations proceed as the capsule descends on its main chute (top left); dust is raised as the retro-rockets fire (top right), and the cloud of dust continues to obscure the capsule as the parachute is jettisoned.

After the deployment of the parachute, a pair of valves on the top of the module automatically open to allow the internal pressure to match that outside. At this time, in preparation for landing, each cosmonaut makes sure that his body is comfortable in his contoured couch and shock-absorbing rods elevate the couches from the floor. At an altitude of 3 km (75 seconds after descending through an altitude of 5.5 km), the basal shield is jettisoned to expose four solid-propellant retro-rockets (DMP) to be used to cushion the landing. With the heavy shield discarded, the rate of descent slows. On a nominal descent, there is ten minutes remaining to landing. Each retro-rocket has 22 jets arranged in two rings near the edge of the module's base. They are fired simultaneously by an altimeter at a height of 1-1.5 metres over the ground to reduce the impact speed to 2-3 m/s, with the shock being absorbed by the couches.3 Once the Soyuz is on the ground, the parachute is jettisoned in order to preclude this from dragging the module across the surface if there is a strong wind.

The landing area is on the flat Kazakh steppe. The 'landing window' usually starts three hours before dawn and ends just before sunrise. In addition to enabling the inorbit manoeuvres to be made in daylight, this schedule permits the recovery team to observe the descent module without being blinded by the rising Sun. If the descent is on target, the recovery helicopters will soon settle close alongside. If the recovery crew is unable to arrive quickly, the spacecraft commander will open the hatch and exit. Because the hatch swings into the cabin towards the flight engineer's side, the research engineer is second to exit, after which the flight engineer transfers to the central couch prior to exiting.

As cosmonauts are under stress during the descent they suffer an 'adrenalin rush', and even when everything functions as intended they can be taken by surprise. For example, the crew of Soyuz 7 were initially confused when, after the deployment of the main chute, they felt fresh air rush into the cabin through the valves designed to equalise the pressure. And on Soyuz 4 the crew were surprised when the shock-absorbers raised their couches just before the landing. The first mission to return in abnormal conditions was Voskhod 2 in March 1965, with cosmonauts Belyayev and Leonov. When the automatic orientation failed, Belyayev did so himself and landed 400 km off-target in a snowy forest, and they had to spend two nights in the frozen capsule surrounded by wolves and bears. Another serious incident occurred in January 1969 during the return of Soyuz 5 with cosmonaut Volynov, when the propulsion module failed to separate and blocked the heat shield as the spacecraft entered the atmosphere. Volynov was alarmed by the rise in temperature and smell of soot in the cabin, but fortunately at an altitude of 80 km the connections between the modules melted, the propulsion module was torn away by the atmospheric drag, and the descent module stabilised. However, it was off-target and the landing was so hard that Volynov suffered broken teeth. Of course, the worst accident occurred during the return of Soyuz 1 in April 1967. Owing to the lax technical discipline of the people who applied the thermal treatment to the descent module, the volumes of the main and reserve parachute containers were reduced, with the result that when

3 The height sensor is a gamma-ray altimeter ('raMMafly^eBOH BbicoTOMep').

The recovery team opens the hatch to help the cosmonauts out of the capsule. On some occasions the capsule comes to rest upright, but here it is on its side, which can be uncomfortable for the crew.

the parachutes were inserted they were packed too tightly.4 At an altitude of 9.5 km the hatch of the main parachute container was jettisoned, as planned. This drew out the pilot chute, which deployed the drogue chute. Unfortunately, the drogue was not able to pull the main chute from its container. Seventeen seconds later, the hatch of

4 The root cause of Komarov's death was the thermal treatment of the descent module and the placing of the parachutes into their containers. Because the parachute containers of both the Soyuz 1 and Soyuz 2 descent modules did not have hatches when they were sent for the application of their thermal treatment, the technicians decided not to ask for the hatches to be supplied and instead 'closed' the openings using improvised covers that did not form a hermetic seal. During the treatment, some molecules of the thermal protective material penetrated the containers and coated their walls, thereby both reducing their volumes and making the smooth interior surfaces rough. When the treatment was finished, the technicians tried to put the parachutes into their containers and, on finding that they would not fit, opted not to inform their managers but instead (according to Mishin) to use some kind of tool to force them in. It is ironic that the early problems suffered by Soyuz 1 led to the cancellation of the launch of the second spacecraft for this joint mission, as otherwise both crews would almost certainly have been killed.

the reserve chute jettisoned and pulled out the reserve chute. What happened next is disputed: one account says that the reserve chute was in the so-called aerodynamic shadow of the drogue; another says that it became twisted with the other lines. But both accounts agree that the parachute was unable to deploy fully.5 In any event, the module struck the ground at a speed exceeding 50 m/s, causing the main instrument panel to break free and crush the chest of Komarov, killing him.

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