Hey . I'll try to help , this question is really confusing...
because the rocket is moving 1000m/s then like it fires out rockets and we don't know what speed those rockets are going at.
Hmm , i'll tell you my attempt , but srsly this question is hard
r = ut + 1/2at^2
r = 240 km = 240000 m
u = 1000m/s
t = 5 mins = 300s
a = ?
240000 = 1000 x 300 + 1/2 x a x (300)^2
240000 = 300000 + 45000a
= - 6000 = 45000a
a = -6000/45000
a = -0.133m/s/s towards the star ...
Oh man i'm sorry i'v never done a complex Question like this b4