Entry

After the space shuttle has reached the entry interface, the next step is to enter the earth's atmosphere and ensure a safe landing.

Overcoming gravity is one of the important problems while getting into space. While coming back, space shuttle must lose speed instead of gaining it. During entry, space shuttle has to slow down considerably. There are 2 possible ways of landing:

 •  Vertical landing- A space shuttle will land with help of rocket power generated by fuel. There is one disadvantage of vertical landing. That it cannot use the atmosphere alone to slow down. Parachutes and parasail have to be employed, but they will help only for small capsules. Splitting it into two parts at the time of re-entry can bring down a large vehicle. Each part can be brought separately with the help of parachute.

•  Horizontal landing- this technique effectively utilizes the atmosphere for landing. It has been used in the U.S. space shuttle since 1981.