Virgin Group founder Richard Branson and five others undertook a trip to the “edge of space”, and reached an altitude of 85 km from Earth before returning. Such a trip is called a Suborbital Flight. 

• Suborbital Flights occur when a spacecraft reaches space, but its velocity is such that it cannot orbit the Earth once they reach there. 

How does Suborbital Flight work? 

• When an object travels at a horizontal speed of about 28,000 km/hr or more, it goes into orbit. Satellites need to reach that threshold speed in order to orbit Earth. 
• Any object traveling slower than 28,000 km/hr must eventually return to Earth. 

• However, Unity spacecraft traveled far enough to reach the “edge of space”. These are suborbital flights because they will not be traveling fast enough to orbit Earth once they reach there. 

Read more: Suborbital flight: Fast enough to reach space, not stay there