The Hammer Of God by Arthur C. Clarke

In a near-future world, a planetary defense team discovers a mountain-sized asteroid, Kali, on a collision course with Earth. Captain Robert Singh and the crew of the spacecraft Goliath attempt to attach a low-thrust engine to slowly deflect the rock, but technical setbacks and sabotage by religious extremists upend the plan. With time running out, they gamble on a daring alternative, forcing humanity to confront the interplay of science, faith, and the collective will to survive.

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