Skepticblog » Why the US Can't Get Astronauts Into Space From sapceman's comment in the middle of the page, I found
Dispelling the Myth of Robotic Efficiency: Why Astronomers Should Support Human Exploration of the Solar System | astrobites It discussed
[1203.6250] Dispelling the myth of robotic efficiency: why human space exploration will tell us more about the Solar System than will robotic exploration alone Quote:
There is a widely held view in the astronomical community that unmanned robotic space vehicles are, and will always be, more efficient explorers of planetary surfaces than astronauts (e.g. Coates, 2001; Clements 2009; Rees 2011). Partly this is due to a common assumption that robotic exploration is cheaper than human exploration (although, as we shall see, this isn't necessarily true if like is compared with like), and partly from the expectation that continued developments in technology will relentlessly increase the capability, and reduce the size and cost, of robotic missions to the point that human exploration will not be able to compete. I will argue below that the experience of human exploration during the Apollo missions, more recent field analogue studies, and trends in robotic space exploration actually all point to exactly the opposite conclusion.
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Courtney Dressing of Astrobites reproduces some of the figures in that paper.
One of them shows curves of how many papers have been published about the results of various lunar missions. The Apollo ones have about 5 times as many as the other ones combined.
That's due to the much larger volume of rocks that the Apollo astronauts had returned with, their greater variety, and various instruments that those astronauts had left on the Moon. That was partly because the astronauts needed to have big spacecraft to keep them alive and to transport them. That great size enabled lots of rocks and instruments to travel with the astronauts.
The downside was that the Apollo program is MUCH more expensive than its automated competition, and that it was supported by Cold-War beat-the-Russians one-upmanship. After it succeeded in beating the Russians to the Moon, a lot of its motivation evaporated, and the last three planned Apollo missions were never flown.
The Russians, for their part, were trying to beat the Americans to the Moon, but they failed miserably, and they later claimed that they were never in the race.
As to astronauts going to Mars, I really don't see it happening any time soon. Just about every spacecraft sent there so far has been sent on some approximation of a Hohmann Transfer Orbit, an orbit with the minimum possible velocity change between a starting and an ending circular orbit. The Earth is at the orbit's closest distance from the Sun, and Mars is at the orbit's farthest distance. This requires that the Earth and Mars have certain relative positions, something that happens about every 2 years. Going to Mars takes about 9 months, one has to stay at Mars for about an Earth year before the two planets have good relative positions for returning, and returning takes another 9 months. That adds up to 2 1/2 (Earth) years.
However, human astronauts have demonstrated much greater dexterity than automated spacecraft, even when wearing spacesuits. For Mars, the round-trip time for radio communication is about 30 minutes, meaning that spacecraft controllers have to work out detailed instructions and radio those instructions to their spacecraft.
Human astronauts also have MUCH better visual recognition than automated spacecraft. Automated vision is still in a rather primitive state, though it has gotten a lot of industrial application for inspections and the like.
Here's a comparison of advantages and disadvantages:
Some of those assessments are rather grotesquely wrong.
Strength? Don't make me laugh. Try a tug-of-war with a car some time.
Endurance? Automated spacecraft can be continuously active, and they can easily survive environments that will quickly kill us.
Perception? We are good at recognizing patterns, and AI is rather far behind there. However, automated spacecraft can and do have a much wider range of "senses".
It didn't talking about powering, and we are FAR behind there. We can't power ourselves by plugging ourselves into an electrical outlet, for instance. We need food, and chemically-complicated food at that. Complete with several kinds of food materials whose molecules would be useless for us if they got even slight rearrangements.
I envy fungi and bacteria; some of them can subsist on a much more limited selection.
Manufacturing them would be difficult and inefficient without catalysts that are very shape-sensitive. But there do exist such catalysts, and several of them were "invented" over 3 billion years ago: enzymes. However, eating organisms requires much more food-organism biomass than human-flesh biomass, which means an even bigger spacecraft.
