Answer:
83067919.256 m/s
Step-by-step explanation:
Time elapsed in according to the clock in the spacecraft = Δt'' = 17.852
Time elapsed in according to mission control = Δt = 17.154
Speed of light = c =3×10⁸ m/s
Time dilation

∴ The speed at which the spacecraft was moving is 83067919.256 m/s