Key steps for Shenzhou-7´s safe return

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Source: CCTV.com | 09-28-2008 13:13

Astronauts aboard the Shenzhou-7 spaceship will have to go through a series of steps before returning to Earth. The Shenzhou spaceship consists of orbital, re-entry and propelling modules.

The first task the astronauts have to do is to lock the hatch of the re-entry module and then separate it from the orbital capsule.

The first task the astronauts have to do is to lock the hatch of the re-entry module and then separate it from the orbital capsule.

If the re-entry module is not correctly locked, the air inside will leak after the separation, threatening the safety of the astronauts.

When the first step is completed, the propelling module will send the re-entry capsule back to an area 140 kilometers away from the ground.

The propelling module will then brake and separate itself from the re-entry module.

"The braking is crucial. If the module's position is incorrect, if its speed is insufficient, or the force inadequate, the whole trajectory will deviate substantially away from the planned landing site."

The third step is for the re-entry capsule to re-adjust its position. In order to land as planned, its positioning must be accurate. Friction with the atmosphere would cause temperatures of over a thousand degrees that could burn the capsule.

The last step is that the parachute of the re-entry module must open immediately while it is 50 kilometers away from  ground.

In addition, the re-entry capsule will go through a blackout area. During this time, communications with the ground will be lost for about one minute. And the capsule has to rely on its own highly automatic control.

Qin Wenbo, Deputy General Commander of Shanghai Aerospace Tech. Research Institute said "That area is the ionized layer. All communications will be blocked then. The capsule will have entered into the brink of atmosphere."

In the fifth step, the re-entry module will slow down sharply while going through the atmosphere. Astronauts will have to undergo pressure several times greater than their weights.

The last -- but crucial -- step is that the parachute of the re-entry module must open immediately while it is 50 kilometers away from ground.

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Editor:Xiong Qu