At $=$

$484$ s after midnight, a spacecraft of mass $1500$ kg is located at position $<9\backslash$times $10^5,5\backslash$times $10^5,-4\backslash$times $10^5>$ m$,$ and at that time an asteroid whose mass is $2\backslash$times $10^15$ kg is located at position $<3\backslash$times $10^5,-8\backslash$times $10^5,-16\backslash$times $10^5>$ m$.$ There are no other objects nearby...Calculate the $($vector$)$ force acting on the spacecraft.At $484$ s the spacecraft's momentum was Pi and at the later time t$=497$s its momentum was Pf Calculate the $($vector$)$ change of momentum