Saludos
Puedes utilizar la funcion explode
Código PHP:
$var="1234 Perez Sanchez Juan Alejandro 456783 LP";
$arrayVar=explode(" ",$var);
//Return array
$arrayVar[0]="1234";
$arrayVar[1]="Perez";
$arrayVar[2]="Sanchez";
$arrayVar[3]="Juan ";
$arrayVar[4]="Alejandro ";
$arrayVar[5]="456783";
$arrayVar[6]="LP";