At launch you will not be able to descend to the surface of a planet but instead you will see a re-entry animation and, I presume, cut to the landing pad.
At launch Elite: Dangerous will be similar to the other incarnations of Elite in that you will be stuck in your cockpit looking out. However David Braben has said he would like to implement moving around inside your ship with functionality such as fighting fires etc.
Also mentioned was the ability to leave your ship, board other people's ships and walk on planetary surfaces as well as in space stations and ground stations. Suggested outcomes by David Braben include sneaking onto another ship, possibly even stealing them as well as big game hunting on planetary surfaces.
