Space is inherently dangerous, but since it's so high visibility (and funded by deep pockets), they can use technology to reduce the risk below most activities. I think they go too far in reducing the risk -- I'd accept a 10% fatality rate for important space missions if everyone was a volunteer, if it improved the rate of progress.
We know how to do diving in worse environments than caves relatively safely -- commercial and naval (Naval diving is working on docks and repairs for the Navy in peacetime vs. military diving, which is the kind of dangerous combat/commando/infiltration/specops missions done by SEALs and UDTs, etc.) diving to 500m is actually relatively safe as a career. This often takes place in HAZMAT environments, zero visibility, etc.
The issue is that recreational/"technical" divers are doing it with much less equipment, and vastly less support staff. A commercial diver has a $3-5mm recompression chamber waiting above, a safety diver ready to splash in, dive medics or medical officers, a dedicated support ship, unlimited surface-supplied gas, heated water in the cold, wired communications, etc. Recreational divers have what they can carry and personally afford to buy.
Naval diving is Navy or Coast Guard (or Army underwater construction) diving done by hard hat divers to repair ships, salvage, do dock maintenance, etc. It is not "all diving done by Navy personnel". They're ND ratings, and while technically part of Naval Special operations, not SEALs. There are probably some special missions where Naval divers have done something special opsy (tapping undersea cables, or salvaging a foreign nation's warship without their knowledge or consent), but it's not routine. Naval diving techniques are basically adapted commercial techniques, and in a lot of cases are more conservative and safer than what cheap commercial contractors use.
SEALs are probably never qualified Naval divers, unless they start out as Naval divers and then switch to SEALs.
What SEALS do -- Combat diving, combat swimming, etc. is called "military diving". That tends to be dangerous, although not as much due to the diving aspects (it's a lot of oxygen or other rebreather use at shallow depths, undersea scooters for long transits, etc.), as due to the other people trying to kill you. Also, at least recently, SEALs mainly engage in combat on land in countries with no contiguous oceans :)
I'd accept a 10% fatality rate for important space missions if everyone was a volunteer, if it improved the rate of progress.
But would the volunteers accept it? Heh, you're "willing to take risks" with other people's lives, that's the most callous thing I've heard this morning.
Not attacking you, just saying your choice of wording is funny. I assume you are probably implying that all the volunteers know of and accept the risk.
During the few moments I've been typing this, I've gotten to thinking, does how someone answers the question "do the ends justify the means?" say much about what sort of person they are? I guess my answer would vary depending on what the ends were. Sometimes, I would answer yes even in situations where it made others disgusted with me. Sometimes I'd say no at the cost of many lives.
We're all a convoluted mix of conflicting ideals, I guess. C'est la vie.
We know how to do diving in worse environments than caves relatively safely -- commercial and naval (Naval diving is working on docks and repairs for the Navy in peacetime vs. military diving, which is the kind of dangerous combat/commando/infiltration/specops missions done by SEALs and UDTs, etc.) diving to 500m is actually relatively safe as a career. This often takes place in HAZMAT environments, zero visibility, etc.
The issue is that recreational/"technical" divers are doing it with much less equipment, and vastly less support staff. A commercial diver has a $3-5mm recompression chamber waiting above, a safety diver ready to splash in, dive medics or medical officers, a dedicated support ship, unlimited surface-supplied gas, heated water in the cold, wired communications, etc. Recreational divers have what they can carry and personally afford to buy.