[bearnard1212 (OP)]

Do you support crewed or uncrewed missions? Nowadays space technology is developing so rapidly as you can see. Personally, I support uncrewed missions. It's much easier and more important secure to send uncrewed missions ( we just don`t have to risk the crew) But still, there is a lot of important stuff in particular missions machines cannot do without humans
What do you think about that?

[Bored chemist]

Why do you think of this as an either /or thing?

[Halc]

Do you support crewed or uncrewed missions? Nowadays space technology is developing so rapidly as you can see. Personally, I support uncrewed missions. It's much easier and more important secure to send uncrewed missions ( we just don`t have to risk the crew) But still, there is a lot of important stuff in particular missions machines cannot do without humans
What do you think about that?

What do you mean by 'support'?  Am I suppose to attend a protest rally if they do the wrong kind?
Whether or not a mission has a human crew depends very much on the purpose of the mission, so a blanket statement that you seek seems not to apply since mission have different purposes.

I can think of very little 'stuff' that machines can't do without the aid of humans. The crew's purpose is rarely to deal with the machines.

[bearnard1212 (OP)]

Do you support crewed or uncrewed missions? Nowadays space technology is developing so rapidly as you can see. Personally, I support uncrewed missions. It's much easier and more important secure to send uncrewed missions ( we just don`t have to risk the crew) But still, there is a lot of important stuff in particular missions machines cannot do without humans
What do you think about that?

What do you mean by 'support'?  Am I suppose to attend a protest rally if they do the wrong kind?
Whether or not a mission has a human crew depends very much on the purpose of the mission, so a blanket statement that you seek seems not to apply since mission have different purposes.

I can think of very little 'stuff' that machines can't do without the aid of humans. The crew's purpose is rarely to deal with the machines.

Yeah, I do agree with you. Manned missions might be dangerous for the crew that is why I prefer robotic missions. But still, they have a large disadvantage, robotic ones are not so capable as manned missions and can less achieve ( as you have already mentioned )

[Hayseed]

Man is not prepared for space travel yet.  First, we move way too slow.  Second, we must move with gravity.  And third, we must have shielding.   And all 3 have been ignored.   We are not even close to manned space travel.  The goal should be speed, gravity and shielding, not useless Mars.  A craft with these features is much more valuable than going to Mars.  We need a solar system run-about craft.

[evan_au]

Manned missions might be dangerous for the crew

Since when has that stopped us?
- Christopher Columbus, journey to Caribbean: Most of his crew did not return
- James Cook, travel to Tahiti: Many of his crew did not return
- The first people attempting to reach the peak of Everest, the North Pole or the South Pole did not return
- Many of the early airplane pilots did not survive.
...and even crossing the road is sometimes lethal!

Going to Mars requires people with "The Right Stuff" (which probably means something slightly different today than it did in the early days of aerospace)

Elon Musk's concern is that the dinosaurs who stayed home did not survive...

[alancalverd]

You can make a machine to satisfy as much of your curiosity as you can imagine before it sets off, but won't necessarily be able to change its research program in the light of what it finds.

The extraordinary adaptability and resourcefulness of humans is very difficult to replicate. Consider Apollo 13. Admittedly your Mars robot may not need to breathe oxygen and get rid of carbon dioxide, but   

The LM carried enough oxygen, but that still left the problem of removing carbon dioxide, which was absorbed by canisters of lithium hydroxide pellets. The LM's stock of canisters, meant to accommodate two astronauts for 45 hours on the Moon, was not enough to support three astronauts for the return journey to Earth.[121] The CM had enough canisters, but they were the wrong shape and size to work in the LM's equipment. Engineers on the ground devised a way to bridge the gap, using plastic, covers ripped from procedures manuals, duct tape, and other items.[122][123] NASA engineers referred to the improvised device as "the mailbox". The procedure for building the device was read to the crew by CAPCOM Joseph Kerwin over the course of an hour, and it was built by Swigert and Haise; carbon dioxide levels began dropping immediately. Lovell later described this improvisation as "a fine example of cooperation between ground and space" 

Would you include the ability to handle duct tape in your Martian robot specification?  If you did so, could the same tools and computer dig up and do wet chemistry on soil samples, assemble a telescope, and change a tyre when the buggy hit a rock?

The fact is that the best machine for answering the questions that interest humans, or fixing things that you didn't expect to go wrong, is another human.

A lot of extraterrestrial R&D so far has been concerned with survival and return to Earth.  If we have solved most of the survival problems and can ignore the return question, we can supply our landing party with a huge range of tools, laboratory instruments and stuff like string and duct tape that might just come in handy. Suppose we found what looked like a mummified whale on Mars. No way we could or would pre-program a machine to explore something so completely unexpected, but a man with a sharp knife could perform a careful dissection that would increase our knowledge of extraterrestrial life by a factor of several zillion in a few hours.

So what is the "right stuff"? Old age (radiogenic cancers take about 10 - 20 years to become clinically significant, so a sexagenarian won't live long enough to suffer, even without radiation shielding), curiosity, manual dexterity, objectivity (there's no point in setting out with any preconceptions) and a total lack of interest in coming home.

Back to the radiation question: one early consequence of radiation damage is cataracts. This can really screw up the mission because our most efficient datagathering system is vision. But some of us old buggers have already had our lenses replaced by material that doesn't degrade nearly as quickly as natural proteins, so we would have a longer useful life than kids half our age!

[Hayseed]

I believe the shielding could probably be solved in 5 years or so.  New material configurations and EM fields for protection.  We already have a gravity solution with simple spin.  If I recall correctly, present residence(space station) has about 1/10 of 1 g.  But it's in free fall.   We have been in space for 5 decades and not used spin.  It will probably only take a net percentage of 1 g to maintain quality of health.  And it would be curious to see what 1.25 g and 1.5 g does to the human body at long term.......possibly with benefits.

There's a steady stream of wind from the sun, possibly some kind of electric sail, could be used to tack the solar system. Probably quite a large structure would be needed, but size doesn't matter as much there.  Only the mass.  Maybe a graphene sail of some sort.  The sail or sails, might also act as a shield.

[Halc]

There's a steady stream of wind from the sun, possibly some kind of electric sail, could be used to tack the solar system.

Tack?  Tacking only works if you have something to dig your keel into.

[alancalverd]

The radiation dose to a wholly "unprotected" person flying to Mars (assuming a couple of millimeters of aluminum in the ship's hull) would be about 100 millisievert. This is around the 5 year limit for radiation workers but, remarkably, is no big deal. The emergency service limit is set at 200 mSv for a single exposure incurred in the saving of life. 

There are places on earth where the natural background exceeds 40 mSv/yr, and the legal limit for workers (20 mSv/yr) is set so that the incidence of fatal cancer induced over a working lifetime is not distinguishable above its natural occurrence (~25%). 1 Sv acquired over a reasonable period leads to a 5% increase in the incidence of cancer that becomes clinically significant some 10 - 20 years later.

Compared with the other risks associated with takeoff, a 200 day journey in a sealed box, and landing on an unprepared surface, the best thing to do with interplanetary radiation is to ignore it. 

Working on the surface of Mars would be long-term tolerable if the suit contains about 0.2 mm of lead. Again this is no big deal as radiologists and cardiologists wear 0.25 - 0.35 mm "lead aprons" at work, and with only 0.3 g gravity, that is no significant burden.   

[alancalverd]

There's a steady stream of wind from the sun, possibly some kind of electric sail, could be used to tack the solar system.

Tack?  Tacking only works if you have something to dig your keel into.

Suppose instead you had a large concave mirror that focussed all the solar energy onto a boiler which evaporated a propellant. We now have a rocket that doesn't require an oxidant so weighs a lot less than any other, and we can direct the exhaust wherever we want. There being no aerodynamic forces on the mirror, we can make is as large and flimsy as we wish, and thus generate as much power as we want.