China's Shenzhou-7 manned spacecraft and three astronauts on board will have to pass six key tests to fulfill their mission, said Zhou Jianping, the program's chief designer, on Thursday.

Test 1: Blastoff

"For any manned space program, the possibility to come across deadly failures is larger during the launch," said Zhou at the Jiuquan satellite launch center of northwestern Gansu Province.

Although the Long-March II-F carrier rocket, to carry the spaceship, had succeeded in bringing six spacecraft to the outer space, a series of contingency plans were made to protect the safety of astronauts, he said.

The 100-meter-high launch tower is equipped with a slide to facilitate astronauts escape from the spaceship when an accident happens.

The control center is 1,500 away from the launch tower in a bid to reduce threat to the ground staff.

Eight contingency modes were designed for the spaceship during the ascent stage, four inside the atmosphere and the other four out of it.

"Jiuquan Satellite Launch Center is confident of a successful blastoff for it has successfully launched more than 100 satellites and spacecraft in the past five decades. We have the world's latest technologies and management," said Cui Jijun, the launch center director.

Test 2: Transfer the orbit

The Shenzhou-7 spaceship will transfer from an elliptic orbit to a circular one in its fifth circle around the earth. Whether it will succeed in this stage will be critical for the spaceship to fulfill all its tasks and land on the scheduled landing area in the timetable, said Zhou.

The spaceship will first travel on the elliptic orbit, 200 km away from the earth at the nearer point and 350 km at the farthest point, and it will transfer to the circular orbit 343 km away from the earth, to make its return trip easier.

Beijing Aerospace Control Center will take in charge of controlling the spaceship at this stage. "We are confident of fulfilling this task as we have performed well in the country's first moon probe mission," said Zhu Mincai, the center's director.

Test 3: Put on space suit

Astronauts will start preparing for the spacewalk in the spaceship's ninth circle around the earth. The most important part is to put on the space suit. The whole preparation will take about14 hours.

Chinese only spent four years in developing its own EVA (extra vehicular activity) suits, named Feitian.

Despite repeated training, it will be the first time for the astronaut to put on it in the outer space. The astronaut must strictly follow the procedure. Any mistake will lead to deadly results, said Zhou.

"It will be much different to put on it in the space from doing it on the earth," said Liu Boming, one of the three astronauts to be on board, "But I can only tell you what is the difference when I am back."

Test 4: airlock

The airlock, a pressure chamber linking the main body of the spaceship to the outside, is new on Shenzhou-7 and was not required on the previous six space flights. Whether it will work properly decides whether the astronaut can finish the spacewalk.

Inside the airlock, the air pressure will reduce to zero before the astronaut steps outside and restore to the normal level inside the module after he returns. The whole procedure must finish within a certain period of time.

"The airlock is well designed and safe," said Zhang Bonan, chief designer of the manned spacecraft system.

Test 5: spacewalk

The highlight of the whole program will be the 30-minute spacewalk when the Shenzhou-7 travels around the earth in the 29th circle.

It will be a test for both the astronauts and the ground staff. The astronaut that walks into the space will take test samples from the surface of the modules and solar battery, cooperating with another astronaut inside. The ground staff must maintain the communication between the control center and spacecraft and provide supports for the astronaut.

Every move must be well done, including opening the door of there-entry module, closing it and sealing it. "It is not easy to do it in the outer space," Zhou said. "If the door is not sealed, there will be a disaster."

"In such an independent task as the spacewalk, it is the psychological factor that affects the astronaut's performance," said Yang Liwei, China's first spaceman and deputy director of the China Astronaut Research and Training Center.

Test 6: blackout area

When the spaceship begins its journey back, it must start its engine at the right time for a second earlier or later will lead to a landing site 9 km away from the planned one.

The re-entry module will go through a "blackout" area when it re-enter the atmosphere, which means all communication with the ground will be weak and even cut off. It will greatly challenge the physical and psychological conditions of the astronauts.

The blackout will disappear when the module reaches the height 40 km from the ground.

"The landing system will search the module and rescue the astronauts as soon as they land. We will try our best to give a perfect end to the mission," said Sui Qisheng, director of the landing system.

(Xinhua News Agency September 25, 2008)