China's second manned space flight will be done by two astronauts over five days in 2005. "Shenzhou-VI will be sent into space sometime in 2005," said Zuo Saichun, a spokesperson of the China Aerospace Science and Technology (CAST). "The spacecraft will make new breakthroughs in China's manned space technology." Unlike Shenzhou-V, a little more than a year ago (in October, 2003), the next flight will see two astronauts fly in space for five days. Their capsule   is designed to be capable of orbiting for a whole week, the spokesperson said. "For the first time, astronauts will enter and live in the orbital module  of the spacecraft to do scientific experiments," said a statement from CAST. CAST did not say what those experiments will be. In Shenzhou-VI, scientists have changed the spacecraft's configuration   to reduce its weight, and tried to improve the performance of on-board equipment. They have also worked to make sure of the energy supply of the spacecraft and further improve its safety. So far, scientists have worked out ways to solve problems on environmental control and life support. Shenzhou-VI will be sent into orbit  atop a Long March  2F rocket.  Meanwhile, a model of the Chang'e-1 satellite is expected to be sent to orbit the moon in two years. The satellite, part of the three-stage programme, would be followed by the landing of an unmanned vehicle on the moon in the second stage by 2010 and collecting samples of lunar soil by 2020 in the final stage, according to Sun Laiyan, director of the China National Space Administration. According to the passage, the following problems should be solved before Shenzhou-VI is sent into space EXCEPT   _  .
environmental control energy supply life support lunar soil collecting