As for existential risk from AI takeover, I don’t think having a self-sustaining civilization on Mars would help much.
If an AI has completed takeover on earth and killed all humans on earth, taking over Mars too does not sound that hard, especially since the human civilization is likely quite fragile. (There might be some edge cases, where you solve the AI control problem well enough to guarantee that all advanced AIs leave Mars alone, but not well enough for AI to leave Australia alone, but I think scenarios like these are extremely unlikely).
For other existential risks, it might be in principle useful, but practically very difficult. Building a self-sustaining city on Mars will take a lot of time and resources. On the scale of centuries, it seems like a viable option though.
As for existential risk from AI takeover, I don’t think having a self-sustaining civilization on Mars would help much.
If an AI has completed takeover on earth and killed all humans on earth, taking over Mars too does not sound that hard, especially since the human civilization is likely quite fragile. (There might be some edge cases, where you solve the AI control problem well enough to guarantee that all advanced AIs leave Mars alone, but not well enough for AI to leave Australia alone, but I think scenarios like these are extremely unlikely).
For other existential risks, it might be in principle useful, but practically very difficult. Building a self-sustaining city on Mars will take a lot of time and resources. On the scale of centuries, it seems like a viable option though.