User talk:Nguyentrongphu/Human mission to Mars (archive)

Entry into the thin and shallow Martian atmosphere will pose significant difficulties with re-entry; compared to Earth with much denser atmosphere, any spacecraft will descend very rapidly to the surface and must be slowed down. Heat shield has to be utilized. NASA is carrying out research on retropropulsive deceleration technologies to develop new approaches to Mars atmospheric entry. A key problem with propulsive techniques is handling the fluid flow problems and attitude control of the descent vehicle during the supersonic retropropulsion phase of the entry and deceleration.