Even with very expensive risk avoidance these kind of missions can be ridiculously failure prone. Just look at how many Mars missions have been lost. Is there

Even with very expensive risk avoidance these kind of missions can be ridiculously failure prone. Just look at how many Mars missions have been lost. Is there really much difference between a process that produces a 20% failure rate and one with 80%-100% (lost all your data)? This would seem like a difficult balance to strike.