This is a simplified analysis. On balance, I don't think there is any consistent moral basis for objecting to space travel that is based on not accidentally des

This is a simplified analysis. On balance, I don't think there is any consistent moral basis for objecting to space travel that is based on not accidentally destroying non-Earth life. Did you have a specific objection in mind? Saying, "It is immoral to risk destroying non-Earth life," would not be enough. One argument is a sort of recursive argument that humans are the best hope for Earth life in the long term, they are also the best hope for solar system life in general. All solar system life is equally doomed—albeit at potentially longer timescales than Earth life.