Simplify the following text for a Grade 9 native English-speaking person.
Original: On 24 March 2006 , the X-37 flew , but a data link failure prevented the free flight and the vehicle returned to the ground still attached to its White Knight carrier .
Simplified: In late March the X-37 flew , but a flaw prevented the free flight and the vehicle returned to the ground still docked with its White Knight carrier .