 Complete the following phrase:  A reusable spacecraft is a class of spacecraft that have been designed with repeated launch, orbit, deorbit and atmospheric reentry in mind. This contrasts with conventional spacecraft which are designed to be expended thrown away, allowed to burn during reentry after use. Examples of reusable spacecraft are spaceplanes such as the Space Shuttle orbiters and the Dream Chaser and space capsules like the SpaceX Dragon. Such spacecraft need mechanisms to prevent the disintegration of the spacecraft and its occupantscargo during reentry. Failure of such systems may be catastrophic, as what happened in the 