I dont Take Credit for finding this Glitch!
Text TUT :
I Use C4 because i think thats works Better!
First get a Valkyrie rocket and you can have any EQUIPMENT and switch the Valkyrie rocket and whatever equipment you choose back and fourth fast as you can
You will Unlock all Challanges from Valkyrie rockets!
Video TUT :
https://www.youtube.com/watch?v=wKBvZnahsD0&feature=player_embedded