[cryptoz]

> What exactly is the need to send humans to Mars?

Lots of reasons, some below. Primarily, the reason to send humans is because we have to in order to ensure the continued survival of (known) life in the universe. Sending a few people to Mars will be the first steps in becoming a multi-planetary civilization, which will reduce our dependency on a single-point-of-failure for all known life.

> Why not robots?

You ask as if we haven't been sending robots to Mars for the last 3-4 decades. (Edit: We should absolutely send robots. We should send way more robots than people. But we should still send people.)

> Is it worth risking a human's life for science, when a robot can do an equally good job?

Not sure if trolling. Humans have collectively agreed that it's worth 10,000+ annual deaths in the USA in exchange for the convenience of cars. So yes, 1-5 human lives on Mars is worth the science that they'd get done.

Also...there are no robot scientists yet. Maybe there will be in the future, but we can't bank on that and allocate budgets to imaginary robotic scientists that are better than humans.

I've been trolled haven't I?

[Amezarak]

> Sending a few people to Mars will be the first steps in becoming a multi-planetary civilization,

I think there is immense value in continued unmanned Mars missions and yes, even in manned missions, but I don't think that a trip to Mars would be a step towards becoming a multi-planetary civilization beyond "we can ferry humans between planets." Mars is not and most likely never will be colonizable. We might have an outpost or a station like the ISS, but Mars' extremely thin atmosphere and low surface gravity (a third of Earth's) means that long-term habitation will never be practical barring extraordinary technological developments in planetary engineering, the medical field, and/or artificial gravity.

Personally I suspect the only long term colonization prospect in the Solar System is Venus - thick atmosphere and near-Earth surface gravity - but for obvious reasons we'd still need extensive terraforming to cool the planet and make the atmosphere breathable - seeding the clouds with oxygen-producing bacteria would be a first step towards both, I suppose.

[danielweber]

Why do you think humans won't be able to live in 3/8g?

[gambiting]

Oh I think we would. But at the moment I think that living on Mars would be almost the same as living on the bottom of the ocean - both would require spending all of the time inside pressurized containers, looking outside through glass. Yet the perspective of looking at the ocean floor is incredibly boring, but perspective of looking at Mars' surface is exciting? Don't get me wrong, it would be AMAZING if we got humans to Mars. But if we are to live inside plastic structures, we can do it just as well on the Moon, which is much easier to reach.

[Amezarak]

> Oh I think we would.

We could. But there are serious health issues associated with living long-term in low-g environments and anyone who spent their whole life there would probably never be able to visit Earth.

[induscreep]

No it's not trolling. I just want to see if a human's workload on space missions can be replaced by a set of sensors and robots.

> Primarily, the reason to send humans is because we have to in order to ensure the continued survival of (known) life in the universe.

Sure, but why not send multiple robots and a bunch of sensors? Humans need food and water to live (don't know how much of the payload will be a year's worth of food/water), and are generally inefficient at converting food sources to energy.

> Humans have collectively agreed that it's worth 10,000+ annual deaths in the USA in exchange for the convenience of cars.

Wrong. This is why we need autonomous cars. Driving is best done by computers, and humans will agree that it is NOT worth 10k+ annual deaths a year just to give humans "the pleasure of driving".

[cryptoz]

Thanks for your reply. I'll address some concerns, but I think we're closer to agreement than earlier actually.

> Sure, but why not send multiple robots and a bunch of sensors?

Well, yes, we absolutely should. We've got a long history of doing this, so we know what their strengths and weaknesses are. We should keep doing this, I think the vast majority of 'things' that we send to Mars for the next 10-20 years should be robots, not people.

> Humans need food and water to live (don't know how much of the payload will be a year's worth of food/water), and are generally inefficient at converting food sources to energy.

This is exactly the reason we need to send them. Since the eventual goal is (or should be, anyway) permanent colonization, it makes sense to send people right away so that they learn how to make food and where to find water. Robots won't be so concerned with this - and frankly, human ingenuity to find ways of making food is probably better done by humans than it is by robots.

> Wrong. This is why we need autonomous cars. Driving is best done by computers, and humans will agree that it is NOT worth 10k+ annual deaths a year just to give humans "the pleasure of driving".

I would agree with you if this had always been the case. But road deaths have persisted for decades without even the promise or idea that we're working towards a real solution. It's just been accepted by people. I agree that this attitude will change we when demonstrate that it doesn't have to be this way anymore.

But for the last ~100 years, humanity has definitely been quite relaxed at risking death just so we can drive cars (or, walk around nearby others who are driving cars).

[mbreese]

Humans, as a species, have a very low bus-factor in planetary terms...

[dllthomas]

I think we're fine if a bus hits the planet.

[bronson]

Not if it's doing 0.999c.

obwhatif https://what-if.xkcd.com/20/

[dllthomas]

That sphere of diamond weighs about 3000x as much as a typical bus. So presumably we'd wind up with 1/60th of Chicxulub, rather than 50x. It'd suck (a lot) - and yeah, "we're fine" wouldn't hold - but I think we'd survive.

Edited to add: I don't know if I mis-read it or if you edited it, but the above was a response to 0.99c.

[taylorwc]

I agree with you on these points, but think the vehicle deaths makes for a poor comparison since we're not really advancing science in the same way. I'm guessing that NASA would have its pick of qualified volunteers for a manned Mars mission because of the science involved; people who would willingly risk their lives.

[dharmach]

> because we have to in order to ensure the continued survival of (known) life in the universe

Why not send bacteria which may evolve or may create environment for other form of life? If by known life you mean human, why is it so important to ensure the continued survival of human species in the universe?

[WallyL]

> If by known life you mean human, why is it so important to ensure the continued survival of human species in the universe?

I know this isn't a constructive comment but... Really? Like you don't see the point at all?

[cryptoz]

> Why not send bacteria which may evolve or may create environment for other form of life?

We should absolutely do that. In fact, we almost certainly will. This isn't mutually exclusive with sending humans, though, it's something we'd do as well. I think the primary function of said bacteria would be to help terraform the planet - warm up the surface, add gasses to the atmosphere, evolve new Martian life forms to continue those processes, etc.

[seanflyon]

> Why not send bacteria which may evolve or may create environment for other form of life?

We should, but there are 2 reasons we are not doings so right now.

1) We don't want to destroy our ability to determine if there was life on Mars in the past, which would be much harder to recognize as martian life if earth life was all around.

2) It is quite difficult to come up with something that could survive and reproduce on Mars.

I don't think (1) is a compelling enough reason and (2) is just another way of saying that it's hard, so I completely agree, we should do it.

[ufmace]

> Sending a few people to Mars will be the first steps in becoming a multi-planetary civilization, which will reduce our dependency on a single-point-of-failure for all known life.

Only if we are able to make the Martian colony self-sufficient. This is quite a problem, as even major nations on Earth aren't really self-sufficient now. Any serious attempt at trying would most likely require tens of thousands of colonists and massive amounts of materiel to be transported to Mars and sustained there. This would require many, many orders of magnitude more resources than any plausible manned mission to Mars, which is already so expensive that nobody seems to be willing to do it.

[danielweber]

A Mars colony would obviously not be an autarky. But after a few decades, equipment could be set up so that it could be self-sufficient if it needed to.

The US could be self-sufficient, too. It's not because trade is too valuable.

[seanflyon]

Yes self sufficiency is hard, we don't even know how hard, but the first step is a colony. A colony that produces or recycles all of its air and water and half of it's food is well within current technology (though still quite difficult) and the perfect way to understand exactly what we need to learn to have a self sufficient colony. Semiconductor fabs can come later.

Just sending people there for a year and a half is a great first step.

[higherpurpose]

Sure, but you don't need to send humans from the first try, though. First send the robots to build up the bases, then you can send humans in those comfy bases with Internet connection, large screens and 3D-printed pizza.

[waterlesscloud]

We're about 40 years after the first success, much less attempt.

[danielweber]

The reference mission for Mars for over 15 years has been to send the hab and a return vehicle in one launch window, and then send the humans in the second. The humans will know before they lift-off that the return vehicle is fully-stocked and waiting for them and has survived landing.

[wvenable]

> Sending a few people to Mars will be the first steps in becoming a multi-planetary civilization, which will reduce our dependency on a single-point-of-failure for all known life.

Except that all planets in our solar system other than Earth are uninhabitable. So what benefit is sending a few humans to very far away and insanely inhospitable place?

It's a suicide mission for whoever goes. We don't have a great success even landing robots on these places. We've never even tried to return from Mars. Lift-off from Earth is hardly perfected!

[cryptoz]

> Except that all planets in our solar system other than Earth are uninhabitable.

So is Canada in the wintertime. We have spent billions (trillions?) of dollars to make it livable here, I don't see any reason we wouldn't think the same about the planets.

> So what benefit is sending a few humans to very far away and insanely inhospitable place?

I think I answered this already. It's a necessary step in building self-sustaining civilizations. Hopefully it won't be so inhospitable for too long. We can probably terraform in a few thousand years.

> It's pretty a suicide mission for whoever goes.

No more so than staying on Earth. Your life here is a suicide mission just the same as any astronaut's life on Mars would be.

> We don't have a great success even landing robots on these places.

We don't have great success at anything we do, when we do it for the first few times. We'll get better.

> We've never even tried to return from Mars. Lit-off from Earth is hardly perfected!

Alright, let's try a return from Mars in the next 5-10 years then. Also, that's sufficient time to increase reliability in Earth lift-offs.

[Dewie]

> So is Canada in the wintertime.

What an outlandish comparison. I know that Canadians seem to pride themselves on how cold it can get in their neck of the woods, but... come on.

Indians and inuits managed to live there even before there was any concept of "dollars" on the American continent. Now, surviving on another planet? It's like comparing swimming in a lake in the fall to swimming in a volcano.

[JoeAltmaier]

Its comparable. Sure Mars is colder, but cold isn't an issue after you have a coat/insulated building. Its really all air food and water.

Air and water come from ... water and electricity. So that leaves food.

It can be hard to grow anything in a greenhouse in the winter - insulation blocks sunlight, which isn't any too bright out there already. So that leaves farming with lights in tanks, underground, or in insulated domes etc. Which will end up costing more than the human infrastructure. E.g. it can take a quarter acre of land to grow food for you; you can live in 500 sq ft. Orders of magnitude different.

[cryptoz]

I don't mean to compare Canada to Mars!

However...it would be completely impossible to sustain a population of 20 million people living at -20deg C for 3 months at a time, without spending significant amount of money on infrastructure specifically dedicated to making sure we don't die from exposure to the elements. We all collectively decided it was worth it a long time ago, and here we are.

Now Canada's a pretty awesome place to be in the winter.

[Dewie]

> However...it would be completely impossible to sustain a population of 20 million people living at -20deg C for 3 months at a time, without spending significant amount of money on infrastructure specifically dedicated to making sure we don't die from exposure to the elements.

What is this fantastical infrastructure that goes beyond the infrastructure that goes into sustaining a Western country (with densely populated pockets)? Compare the infrastructure to, say, middle latitude USA (latitude equal to NYC).

[cryptoz]

I'll list a few:

Many of our cities are architected entirely differently. Most of them have vast underground components (Montreal, Calgary, Ottawa, etc) to aid in keeping the city livable and dense, while not having to go outside.

Our electricity generating requirements are pretty crazy in the winter, to heat all the buildings. Any gap in insulation will cause deaths.

Our construction industry is currently in upheaval, as new techniques are being invented to enable more growth in the cold climate. New concrete insulation tech, new building designs and materials, etc.

I'm not trying to say it's nearly impossible, or outrageously expensive, or anything. But, it's expensive to build out to a stage where we can reasonably house millions of people through the winters. Worth it, though, and hopefully good preparation for space travel / Mars colonization when the time comes.

[angersock]

You know, I'm quite sure those same arguments were made to the early explorers of the New World, back to the nutty Vikings and others.

[thisGuysAccount]

Even as recently as mass immigration to America. People who got on the boats across the Atlantic weren't coming back, and communication was slow.

Some people just want to go.

[wvenable]

I'm pretty sure the New World was actually habitable.