Asteroid Apophis (previously designed 2004 MN4) was first discovered in June 2004. From its first observations, Apophis was revealed to be a special study case in as much as, it reached the level 4 of Torino scale with a high probability of collision in 2029. New observations eliminated all danger for 2029. But, because of a deep close encounter in 2029 (˜38000 km), the asteroid will be put on a chaotic-like orbit and some risks of collision in 2036 occur if the asteroid goes through a very small region called keyhole. Now, its orbit is quite well known and thanks to additional observations, the risk for the short term seems to disappear. But what about the long term? As far as the Earth-impact threat study is concerned, the deep 2029-close encounter is an opportunity for space missions towards Apophis. With our technologies, to deflect an asteroid, we can only act from the source. Many deflection missions were studied, from the hardest (nuclear weapons), to the softest (shadow mission). But in order to prepare such missions, we have to be sure that the asteroid is really on an impact trajectory. Moreover, if it is the case, we have to be sure that it won't be put on the trajectory of other keyholes. To this aim, we need a good knowledge of the 2029 region uncertainty and we will analyse the impact of the new observations of March 2011.