Looks like things aren't going as expected.
BBC NEWS | Asia-Pacific | China's spacecraft orbit 'slips'It's likely not the gravitational pull - if it's in orbit it's still affected constantly by gravity - but instead air friction. There's a picture of the spacecraft, and it looks a bit on the draggy side. It doesn't take much friction to slow the craft - it just has to be steady. And they don't say what the orbital altitude is - that makes a big difference. If they're 5 or 10 miles too low, the resultant friction and drag would require a boost, or they're going to be coming down a bit early and likely nowhere near their intended landing area....China's Shenzhou VI spacecraft is not orbiting exactly as planned and will have to be restored to its original trajectory, state-run media say.
The "orbit maintenance operation" would take place early on Friday morning, said official news agency Xinhua.Gravity has drawn Shenzhou VI too close to earth, the agency said.
Shenzhou VI, which has two astronauts on board, is in a low enough orbit to be affected by the Earth's gravitational pull.
As I've said before - good luck to them!
J.