UPDATE: Added soft landing retro rockets and landing legs, pressing 3 will activate the retro rockets, this is recommended to be used right before you touch down while returning to Kerbin, and hitting G will extend the hidden landing legs. This allows you to land at roughly 2m/s as apposed to the 6m/s without them. This is particularly useful if you are going to land over water, or on any unstable ground. The retro firing rockets is a feature included in all manned capsules, however the 3 landing legs was inspired by the SpaceX Dragon capsule.