Also - why rush humans as quickly as possible to the place in the inner solar system most vulnerable to Earth microbes? We want to find native Mars life there, if it exists. It is easy to find life if you bring it with you yourself, but that would be the worst possible anticlimax of our search for life in the solar system. Especially if we found that there was some vulnerable form of early life on Mars, say, RNA based life which on Earth got made extinct by DNA life, until just before the humans got there. We must make sure this can't happen.

The Moon is also resource rich. It has some resources that Mars doesn't have indeed. It is also a safer place to explore, closer to Earth, and more likely to have economic value for Earth.

This is the ESA video about ideas for small robotic missions first, followed by Antarctic base type settlements on the peaks of eternal light at the lunar poles

Then as we do so, we continue robotic exploration of the solar system, and find out what humans do best, and what robots do best, starting off with humans on the Moon. Then continue outwards in an open fashion, building on what we've learnt.

Later on we can explore Mars from orbit and its two moons, Phobos and Deimos. Meanwhile continue to explore Mars robotically, and also later, telerobotic exploration from orbit. We can also send human explorers to the Venus clouds, and eventually to the asteroids, to Mercury and to Jupiter's moon Callisto.

In this approach, science and planetary protection is central. Space settlement happens because you are there for a purpose. And as with the Antarctic bases - once we are there doing good science, with science as the motivation, then it would be an on going permanent first step into space.

Missions motivated by science continue to grow, and engage the public. No suggestion that we should stop exploring Antarctica because of the cost of the science exploration there. What's more, they can also have overwhelmingly positive outcomes too, especially if we make new discoveries about biology and evolution.

So the basic ideas are.

• The Moon is resource rich, not resource poor. It has metals such as titanium, aluminium, calcium (which is as good as copper in vacuum conditions, can be hammered, made into wires etc, higher melting point than copper, light weight and an excellent conductor), and iron as the pure metal in powder form. It has volatiles such as water ice, dry ice, ammonia also in ice form, at the poles. Many millions of tons of each probably. The peaks of eternal light at the poles have sunlight nearly 24/7 with breaks of a few hours, or at most an Earth day or two, and have a steady temperature comfortable for humans - far more hospitable than Mars in terms of temperature. Greenhouses are as easy to construct as on Mars with its near vacuum for an atmosphere, and don't need constant input of carbon dioxide, indeed usually it's a nuisance gas to be scrubbed and vented from habitats. The vacuum itself is a resource. The ice at the poles, and possibly also in caves is also a resource that could be used for fuel. It has caves, like Mars, but in the lunar gravity it may have caves up to five kilometers in diameter, large enough to fit an entire city within. When you use ideas developed for Mars to examine the Moon it may seem resource poor, but when you examine it in its own right, it is resource rich.
• The Moon is of great interest for science. There are many things to discover. For instance we don't yet know the age of the south pole Aitken basin, oldest and deepest impact crater on the Moon. We haven't explored its caves at all, or the ice at the lunar poles. It is predicted to have at least 200 kilograms of meteorites from Earth for every square kilometer of the surface and may also have meteorites from early Mars and Venus. The polar ice may trap organics from throughout the history of our solar system, and also shed light on processes that create organics by cosmic radiation interacting with comet ice. There may indeed be extraterrestrial sources of organics throughout the lunar surface (recent result from reanalysis of the Apollo samples). The Moon may still be active, with evidence of recently resurfaced regions. We still don't fully understand the history of volcanism on the Moon. There may be deep water ice rich mantle layers from Theia., the body that collided with proto Earth to create the Moon. We know little about the internal structure of the Moon as yet. It's also an ideal place to build passively cooled infrared telescopes (possibly liquid mirror based) at the poles, and low frequency radio telescopes in the radio dark far side, both accessible from a mission based at its poles. The low frequency radio observations would open up a frequency range that we can't explore from Earth.
• The Moon is far safer as a first destination for humans, with ability to get back to Earth in days, resupply within days, and trouble shoot from Earth with one second delay time only. A base on the Moon could have lifeboat type ships for all the crew on standby ready to take them back to Earth within two days in the case of any emergency. While a mission to Mars is like a long sea voyage without lifeboats. The only way to get back takes at least six months, and (depending on the mission) it could be around two years before you can get back to Earth if there is some problem soon after you leave Earth and you are already on your way to Mars.
  
  On the Moon, we can learn how to keep humans alive in space with minimal resupply from Earth, ideally for years on end. Until we can achieve that, it is just not safe to send humans to Mars. Look at how many spaceship giros failed until the issues were sorted out. It doesn't solve the issue to send duplicate machinery if the duplicates have the same issues as the original. And trouble shooting at the distance of Mars with a 48 minutes maximum round trip time is bound to be harder than for the Moon. A situation like the Apollo 13 "Okay, Houston, we've had a problem here." would find astronauts on Mars very much on their own having to make many decisions on the spot, with Earth only able to advise them based on things they told Earth 48 minutes earlier. (See the transcripts, and imagine how it would play out with a 48 minute delay).
• There are many places in the solar system we could settle and perhaps eventually colonize. The Moon, free space habitats using materials from the asteroid belt, cloud top layers of Venus, Jupiter's moon Callisto (outside of its radiation belt), etc.
• We don't know which gravity levels humans need for health, or what spin rates we can tolerate. So it's impossible to say which of the many proposals are optimal for humans.
• Everything humans need in space is available in the asteroid belt and there are enough resources there to build habitats with a thousand times Earth's land area. This is the most flexible of all as you can site the habitats anywhere in the solar system, with whatever spin rate, atmosphere etc that you prefer. Including simulating Mars if you so wish.
• Terraforming Mars is a far off dream, the envisioned end of a thousands of years long sustained megatechnology project, with much to go wrong. With our so limited knowledge, how can we know what our descendants a thousand years from now would want, or that we can achieve it, and how can we commit to bringing a new baby habitable planet to life in our galaxy after less than a hundred years of experience of spaceflight? Attempting to make a new habitable planet is an endeavour with responsibilities as well as opportunity.
• Earth is the best place for a backup and to rebuild civilization for those that worry about end of the world disasters. That's because no disaster could make Earth as uninhabitable as Mars and some humans would survive anything that is likely to happen. Because we live in a relatively quiet time in our solar system and relatively quiet region of the galaxy.
  
  There are no natural disasters that could make Earth anything like as uninhabitable as Mars and humans would survive them all. We are so adaptable, that we would surely be amongst the 20% of species that survive even after a giant asteroid impact. And Mars, with its radiation levels due to cosmic radiation and solar storms higher than you'd have on Earth after a global nuclear war, no oxygen to breathe, no liquid water, is far far more inhospitable than Earth could ever be after the worst of cosmological disasters.
  
  While it makes little sense to go into space to set up a highly technological society if what you are scared of are disasters caused by high technology. A future with colonies in space would have easy transport back and forth, so they would not be geographically isolated from Earth.
• Instead, we should go into space to help save and restore the Earth, to protect it against asteroids, to move damaging mining operations into space, for solar power, to mine materials from space for Earth. We should have protection and sustenance of our planet as our first priority.
• Mars is proving to have much more potential for surface and near surface life than ever realized before. This makes it vulnerable to Earth microbes that could colonize these potential habitats. They would be spread throughout the planet in the dust storms, and could land there as a result of human spaceship crashes on Mars. The problem is not humans, but our microbe hitchhikers. How can it be good policy to give microbes on human occupied spacecraft a "special pass" to contaminate Mars? To see how vulnerable it could be, consider the case where it has a form of RNA based life which has become extinct on Earth due to the evolution of DNA? Until we know what is there, we can't know how vulnerable it might be or otherwise.
• We have protection guidelines even on Earth to stop microbial contamination of vulnerable habitats . You would not send humans in a bathyscape into the subglacial lake Vostok in Antarctica. If some adventurer was to propose such a mission, he or she would be advised that it can't be done, because we have to protect the habitat there from introduced microbes from the surface. So how can it be right to relax planetary protection guidelines for Mars just because humans want to go there?
• Mars can be explored from orbit more effectively than from the surface using telerobotics. This is an exciting mission for humans. It's moons are also interesting places to explore in their own right. Deimos may well have ice, and Phobos is thought to have material in its regolith from the entire history of Mars, or at least, back to when it first formed or was captured. Probably back to times when Mars had liquid water on its surface. These missions can be designed in a way that is safe for Mars, no possibility of a crash landing.
• Humans don't have special advantages for Mars surface missions. A robot can sit in one place for years if needed, with only a trickle of sunlight. Robots can explore caves and cliffs far too dangerous for humans. Even small robots can be light enough to fly in the near vacuum atmosphere. Humans in spacesuits are clumsy, and it takes a long time to put them on, and they are vulnerable to danger in a spacesuit. And robots can drill as easily as humans and probably more so. Humans have great advantages for on the spot decision making, fine control and creative approaches to problems - but this can be done as easily from orbit, and more safely.
• In orbit, you can explore anywhere on Mars via immersive virtual reality type direct experience of the surface. This may well use techniques from the computer games industry, which gets far more software development than ever goes into space missions. Future astronauts in orbit around Mars may use the equivalent of the Occulus Rift for binocular vision, and Virtuix Omni for an omnidirectional platform to let you walk around on the surface - and with haptic feedback so that you can feel the things you touch on the surface. Everything streamed in real time back to Earth as immersive 3D HD video, and building up a virtual reality version of the surface.
• We can explore the Mars surface for life with miniaturized life detection instruments on a chip, that just a decade ago filled an entire laboratory. The authors of Safe on Mars actually say that in situ exploration would be more effective than a sample return, if we only had the equipment to do so.
  

  "As stated above, there are currently no measurement techniques or capabilities available for such in situ testing. If such capabilities were to become available, one advantage is that the experiment would not be limited by the small amount of material that a Mars sample return mission would provide. What is more, with the use of rovers, an in situ experiment could be conducted over a wide range of locations."
  (Page 41 of Safe on Mars)

  We have that now, and what's more, the Mars surface is much more complex than it seemed back then. It also has organics from meteorites - all the organics discovered so far are expected to be from meteorites.
  
  As eight exobiologists wrote in in a white paper submitted to the 2012 decadal survey, "In the worst scenario, we would mortgage the exploration program to return an arbitrary sample that proves to be as ambiguous with respect to the search for life as ALH84001."
  
  A Mars sample return will not prove that Mars is safe for humans, or that humans are safe for Mars. It is just too little information from such a complex planet - and not a cost effective way to search for life on Mars. It is of more value as a technology demo at this stage.
• Methods designed for human missions to the surface can be used for our robots also, so that they can travel faster, and explore more in each day. We can generate fuel in situ using hydrogen feedstock from Earth just as for human mission proposals. Or we can use solar power and batteries, adapting the Mars One idea to spread a large area of thin film solar photovoltaics over the Mars surface for power. The Apollo lunar roving vehicle had a rated top speed of 8 km / hour (though it could go faster), weighed 210 kg, for the entire vehicle, and had a range of 92 km, nearly twice the total distance Opportunity covered in ten years. So it's not lack of power that limits our rovers - they could go much faster if there was the need to design them to do so.
• We should return samples from Mars either sterilized or to above GEO, or both, at least for preliminary investigation. It makes much more sense to study in situ first - or in telerobotic facilities above GEO, to find out what is there. Then we may decide that there is nothing there that would be damaged by sterilization, just sterilize and return to Earth. Or may decide that elaborate precautions are needed. Or may decide that Earth microbes are not vulnerable to whatever is there, e.g. early RNA based life. Whatever the decision, it should be based on knowing what is there.
• If we show that it can be done on the Moon, this will actually help human exploration of the rest of the solar system, not hinder it. The amount we spend on human spaceflight is tiny. The ISS cost a little over $8 per year per person for the US, and the ESA estimates its contribution as one euro per person for the entire project - less than the price of a single cup of coffee.
  
  Saying that we have to choose between sending humans to the Moon, or to Mars or Jupiter or Venus or Mercury or the asteroid belt is a bit like saying we have to choose between sending satellites to LEO or GEO. We send satellites to both, and can do so because everyone can see the value to Earth. Once people see the value of human exploration, the finance will be easy to find. It will be easier and safer to demonstrate the value of humans in space on the Moon and in the Earth Moon system first.
  
  In this vision we continue with robotic exploration of the solar system, and send humans to other places once it is safe and worthwhile to do so.
• The same open ended principle should be used for all our explorations. Rather than grand overarching plans such as terraforming, or sample return to a facility designed to contain all conceivable types of exobiology, or boots on Mars - or future cities in space based on assumptions about human spin rate and gravity tolerance - we need an open step by step approach. At each stage we learn from what we have found so far, and need the ability to be able to adapt and change our goals rapidly.
• This approach of open discovery is exciting and inspiring. Instead of having as our objective to turn anywhere in space that is remotely habitable into our best approximation of Earth - the idea rather is to explore and discover what is there. And until we know a lot more about what is there, we should not close off future possibilities for ourselves, our descendants and all future civilizations on Earth. For instance if we introduce Earth life to Mars in an irreversible way, then this will create a new geological era on Mars and for all future time, and nobody will be able to study Mars as it was before introduction of Earth life. Also lifeforms introduced accidentally in this fashion, such as methanogens, methanotrophs, aerobes (in spore form), and primary consumers that eat algae and other beneficial microbes may hamper future attempts to transform Mars in other directions. With less than a century of space exploration, we have plenty of time to do such things in the future, and there is no need to rush into irreversible decisions like that as quickly as possible.
• The same principle should be used generally - an open ended approach which keeps future options open. We are not yet at the point where we have enough understanding to close down on future possibilities by doing actions with irreversible consequences.
• In this approach, planetary protection and biological reversibility are core principles. This does not mean that we can never send humans to the Mars surface. That's for future discussion once we have a better understanding of ourselves and of our solar system. It is impossible at this stage to even know for sure what the issues will be by the time we might need to make that decision, which on this vision would be at least some decades into the future (you need time to explore Mars reasonably thoroughly first). Meanwhile we have many exciting places for them to explore, including exploring Mars itself via telepresence - and many other exciting experiments in human settlement to try closer to hand.

For the vision in full with details, see my "Case For Moon - New Positive Future For Humans In Space - Open Ended With Planetary Protection At Its Heart". 

FACEBOOK GROUP

I've made a new facebook group which you can join to discuss this and other visions for human exploration with planetary protection and biological reversibility as core principles. Case for Moon for Humans - Open Ended with Planetary Protection at its Core

Are you keen on humans in space, but skeptical about colonization of Mars as our first objective for space exploration? Do you think we will start with settlements supported from Earth, such as we already have in inhospitable places such as Antarctica? Do you think our exploration should be open ended with science as a core objective, and planetary protection and reversible biological exploration as core principles?

Do you see the Moon as an exciting first place to visit and explore, and see robots as our mobile sense organs in the solar system? Do you think that it's not yet the time to relax planetary protection guidelines, and that there is nothing special about microbes on human spacecraft that would make Mars less vulnerable to them? Then this may be a vision for you.

This is an executive summary of my new 76 page online article and booklet "Case For Moon - New Positive Future For Humans In Space - Open Ended With Planetary Protection At Its Heart" - also available as a kindle booklet.
 

The Moon is interesting in its own right. To ignore the Moon is like ignoring Antarctica because someone landed there in the nineteenth century, saying that Antarctica is already "done". It's the closest place to us in space which we can explore on the ground, and also the easiest, and safest to explore. If we can't explore our Moon, we have no chance of exploring Mars.

Also - why rush humans as quickly as possible to the place in the inner solar system most vulnerable to Earth microbes? We want to find native Mars life there, if it exists. It is easy to find life if you bring it with you yourself, but that would be the worst possible anticlimax of our search for life in the solar system. Especially if we found that there was some vulnerable form of early life on Mars, say, RNA based life which on Earth got made extinct by DNA life, until just before the humans got there. We must make sure this can't happen.

The Moon is also resource rich. It has some resources that Mars doesn't have indeed. It is also a safer place to explore, closer to Earth, and more likely to have economic value for Earth.

This is the ESA video about ideas for small robotic missions first, followed by Antarctic base type settlements on the peaks of eternal light at the lunar poles

Then as we do so, we continue robotic exploration of the solar system, and find out what humans do best, and what robots do best, starting off with humans on the Moon. Then continue outwards in an open fashion, building on what we've learnt.

Later on we can explore Mars from orbit and its two moons, Phobos and Deimos. Meanwhile continue to explore Mars robotically, and also later, telerobotic exploration from orbit. We can also send human explorers to the Venus clouds, and eventually to the asteroids, to Mercury and to Jupiter's moon Callisto.

In this approach, science and planetary protection is central. Space settlement happens because you are there for a purpose. And as with the Antarctic bases - once we are there doing good science, with science as the motivation, then it would be an on going permanent first step into space.

Missions motivated by science continue to grow, and engage the public. No suggestion that we should stop exploring Antarctica because of the cost of the science exploration there. What's more, they can also have overwhelmingly positive outcomes too, especially if we make new discoveries about biology and evolution.

So the basic ideas are.

• The Moon is resource rich, not resource poor. It has metals such as titanium, aluminium, calcium (which is as good as copper in vacuum conditions, can be hammered, made into wires etc, higher melting point than copper, light weight and an excellent conductor), and iron as the pure metal in powder form. It has volatiles such as water ice, dry ice, ammonia also in ice form, at the poles. Many millions of tons of each probably. The peaks of eternal light at the poles have sunlight nearly 24/7 with breaks of a few hours, or at most an Earth day or two, and have a steady temperature comfortable for humans - far more hospitable than Mars in terms of temperature. Greenhouses are as easy to construct as on Mars with its near vacuum for an atmosphere, and don't need constant input of carbon dioxide, indeed usually it's a nuisance gas to be scrubbed and vented from habitats. The vacuum itself is a resource. The ice at the poles, and possibly also in caves is also a resource that could be used for fuel. It has caves, like Mars, but in the lunar gravity it may have caves up to five kilometers in diameter, large enough to fit an entire city within. When you use ideas developed for Mars to examine the Moon it may seem resource poor, but when you examine it in its own right, it is resource rich.
• The Moon is of great interest for science. There are many things to discover. For instance we don't yet know the age of the south pole Aitken basin, oldest and deepest impact crater on the Moon. We haven't explored its caves at all, or the ice at the lunar poles. It is predicted to have at least 200 kilograms of meteorites from Earth for every square kilometer of the surface and may also have meteorites from early Mars and Venus. The polar ice may trap organics from throughout the history of our solar system, and also shed light on processes that create organics by cosmic radiation interacting with comet ice. There may indeed be extraterrestrial sources of organics throughout the lunar surface (recent result from reanalysis of the Apollo samples). The Moon may still be active, with evidence of recently resurfaced regions. We still don't fully understand the history of volcanism on the Moon. There may be deep water ice rich mantle layers from Theia., the body that collided with proto Earth to create the Moon. We know little about the internal structure of the Moon as yet. It's also an ideal place to build passively cooled infrared telescopes (possibly liquid mirror based) at the poles, and low frequency radio telescopes in the radio dark far side, both accessible from a mission based at its poles. The low frequency radio observations would open up a frequency range that we can't explore from Earth.
• The Moon is far safer as a first destination for humans, with ability to get back to Earth in days, resupply within days, and trouble shoot from Earth with one second delay time only. A base on the Moon could have lifeboat type ships for all the crew on standby ready to take them back to Earth within two days in the case of any emergency. While a mission to Mars is like a long sea voyage without lifeboats. The only way to get back takes at least six months, and (depending on the mission) it could be around two years before you can get back to Earth if there is some problem soon after you leave Earth and you are already on your way to Mars.
  
  On the Moon, we can learn how to keep humans alive in space with minimal resupply from Earth, ideally for years on end. Until we can achieve that, it is just not safe to send humans to Mars. Look at how many spaceship giros failed until the issues were sorted out. It doesn't solve the issue to send duplicate machinery if the duplicates have the same issues as the original. And trouble shooting at the distance of Mars with a 48 minutes maximum round trip time is bound to be harder than for the Moon. A situation like the Apollo 13 "Okay, Houston, we've had a problem here." would find astronauts on Mars very much on their own having to make many decisions on the spot, with Earth only able to advise them based on things they told Earth 48 minutes earlier. (See the transcripts, and imagine how it would play out with a 48 minute delay).
• There are many places in the solar system we could settle and perhaps eventually colonize. The Moon, free space habitats using materials from the asteroid belt, cloud top layers of Venus, Jupiter's moon Callisto (outside of its radiation belt), etc.
• We don't know which gravity levels humans need for health, or what spin rates we can tolerate. So it's impossible to say which of the many proposals are optimal for humans.
• Everything humans need in space is available in the asteroid belt and there are enough resources there to build habitats with a thousand times Earth's land area. This is the most flexible of all as you can site the habitats anywhere in the solar system, with whatever spin rate, atmosphere etc that you prefer. Including simulating Mars if you so wish.
• Terraforming Mars is a far off dream, the envisioned end of a thousands of years long sustained megatechnology project, with much to go wrong. With our so limited knowledge, how can we know what our descendants a thousand years from now would want, or that we can achieve it, and how can we commit to bringing a new baby habitable planet to life in our galaxy after less than a hundred years of experience of spaceflight? Attempting to make a new habitable planet is an endeavour with responsibilities as well as opportunity.
• Earth is the best place for a backup and to rebuild civilization for those that worry about end of the world disasters. That's because no disaster could make Earth as uninhabitable as Mars and some humans would survive anything that is likely to happen. Because we live in a relatively quiet time in our solar system and relatively quiet region of the galaxy.
  
  There are no natural disasters that could make Earth anything like as uninhabitable as Mars and humans would survive them all. We are so adaptable, that we would surely be amongst the 20% of species that survive even after a giant asteroid impact. And Mars, with its radiation levels due to cosmic radiation and solar storms higher than you'd have on Earth after a global nuclear war, no oxygen to breathe, no liquid water, is far far more inhospitable than Earth could ever be after the worst of cosmological disasters.
  
  While it makes little sense to go into space to set up a highly technological society if what you are scared of are disasters caused by high technology. A future with colonies in space would have easy transport back and forth, so they would not be geographically isolated from Earth.
• Instead, we should go into space to help save and restore the Earth, to protect it against asteroids, to move damaging mining operations into space, for solar power, to mine materials from space for Earth. We should have protection and sustenance of our planet as our first priority.
• Mars is proving to have much more potential for surface and near surface life than ever realized before. This makes it vulnerable to Earth microbes that could colonize these potential habitats. They would be spread throughout the planet in the dust storms, and could land there as a result of human spaceship crashes on Mars. The problem is not humans, but our microbe hitchhikers. How can it be good policy to give microbes on human occupied spacecraft a "special pass" to contaminate Mars? To see how vulnerable it could be, consider the case where it has a form of RNA based life which has become extinct on Earth due to the evolution of DNA? Until we know what is there, we can't know how vulnerable it might be or otherwise.
• We have protection guidelines even on Earth to stop microbial contamination of vulnerable habitats . You would not send humans in a bathyscape into the subglacial lake Vostok in Antarctica. If some adventurer was to propose such a mission, he or she would be advised that it can't be done, because we have to protect the habitat there from introduced microbes from the surface. So how can it be right to relax planetary protection guidelines for Mars just because humans want to go there?
• Mars can be explored from orbit more effectively than from the surface using telerobotics. This is an exciting mission for humans. It's moons are also interesting places to explore in their own right. Deimos may well have ice, and Phobos is thought to have material in its regolith from the entire history of Mars, or at least, back to when it first formed or was captured. Probably back to times when Mars had liquid water on its surface. These missions can be designed in a way that is safe for Mars, no possibility of a crash landing.
• Humans don't have special advantages for Mars surface missions. A robot can sit in one place for years if needed, with only a trickle of sunlight. Robots can explore caves and cliffs far too dangerous for humans. Even small robots can be light enough to fly in the near vacuum atmosphere. Humans in spacesuits are clumsy, and it takes a long time to put them on, and they are vulnerable to danger in a spacesuit. And robots can drill as easily as humans and probably more so. Humans have great advantages for on the spot decision making, fine control and creative approaches to problems - but this can be done as easily from orbit, and more safely.
• In orbit, you can explore anywhere on Mars via immersive virtual reality type direct experience of the surface. This may well use techniques from the computer games industry, which gets far more software development than ever goes into space missions. Future astronauts in orbit around Mars may use the equivalent of the Occulus Rift for binocular vision, and Virtuix Omni for an omnidirectional platform to let you walk around on the surface - and with haptic feedback so that you can feel the things you touch on the surface. Everything streamed in real time back to Earth as immersive 3D HD video, and building up a virtual reality version of the surface.
• We can explore the Mars surface for life with miniaturized life detection instruments on a chip, that just a decade ago filled an entire laboratory. The authors of Safe on Mars actually say that in situ exploration would be more effective than a sample return, if we only had the equipment to do so.
  

  "As stated above, there are currently no measurement techniques or capabilities available for such in situ testing. If such capabilities were to become available, one advantage is that the experiment would not be limited by the small amount of material that a Mars sample return mission would provide. What is more, with the use of rovers, an in situ experiment could be conducted over a wide range of locations."
  (Page 41 of Safe on Mars)

  We have that now, and what's more, the Mars surface is much more complex than it seemed back then. It also has organics from meteorites - all the organics discovered so far are expected to be from meteorites.
  
  As eight exobiologists wrote in in a white paper submitted to the 2012 decadal survey, "In the worst scenario, we would mortgage the exploration program to return an arbitrary sample that proves to be as ambiguous with respect to the search for life as ALH84001."
  
  A Mars sample return will not prove that Mars is safe for humans, or that humans are safe for Mars. It is just too little information from such a complex planet - and not a cost effective way to search for life on Mars. It is of more value as a technology demo at this stage.
• Methods designed for human missions to the surface can be used for our robots also, so that they can travel faster, and explore more in each day. We can generate fuel in situ using hydrogen feedstock from Earth just as for human mission proposals. Or we can use solar power and batteries, adapting the Mars One idea to spread a large area of thin film solar photovoltaics over the Mars surface for power. The Apollo lunar roving vehicle had a rated top speed of 8 km / hour (though it could go faster), weighed 210 kg, for the entire vehicle, and had a range of 92 km, nearly twice the total distance Opportunity covered in ten years. So it's not lack of power that limits our rovers - they could go much faster if there was the need to design them to do so.
• We should return samples from Mars either sterilized or to above GEO, or both, at least for preliminary investigation. It makes much more sense to study in situ first - or in telerobotic facilities above GEO, to find out what is there. Then we may decide that there is nothing there that would be damaged by sterilization, just sterilize and return to Earth. Or may decide that elaborate precautions are needed. Or may decide that Earth microbes are not vulnerable to whatever is there, e.g. early RNA based life. Whatever the decision, it should be based on knowing what is there.
• If we show that it can be done on the Moon, this will actually help human exploration of the rest of the solar system, not hinder it. The amount we spend on human spaceflight is tiny. The ISS cost a little over $8 per year per person for the US, and the ESA estimates its contribution as one euro per person for the entire project - less than the price of a single cup of coffee.
  
  Saying that we have to choose between sending humans to the Moon, or to Mars or Jupiter or Venus or Mercury or the asteroid belt is a bit like saying we have to choose between sending satellites to LEO or GEO. We send satellites to both, and can do so because everyone can see the value to Earth. Once people see the value of human exploration, the finance will be easy to find. It will be easier and safer to demonstrate the value of humans in space on the Moon and in the Earth Moon system first.
  
  In this vision we continue with robotic exploration of the solar system, and send humans to other places once it is safe and worthwhile to do so.
• The same open ended principle should be used for all our explorations. Rather than grand overarching plans such as terraforming, or sample return to a facility designed to contain all conceivable types of exobiology, or boots on Mars - or future cities in space based on assumptions about human spin rate and gravity tolerance - we need an open step by step approach. At each stage we learn from what we have found so far, and need the ability to be able to adapt and change our goals rapidly.
• This approach of open discovery is exciting and inspiring. Instead of having as our objective to turn anywhere in space that is remotely habitable into our best approximation of Earth - the idea rather is to explore and discover what is there. And until we know a lot more about what is there, we should not close off future possibilities for ourselves, our descendants and all future civilizations on Earth. For instance if we introduce Earth life to Mars in an irreversible way, then this will create a new geological era on Mars and for all future time, and nobody will be able to study Mars as it was before introduction of Earth life. Also lifeforms introduced accidentally in this fashion, such as methanogens, methanotrophs, aerobes (in spore form), and primary consumers that eat algae and other beneficial microbes may hamper future attempts to transform Mars in other directions. With less than a century of space exploration, we have plenty of time to do such things in the future, and there is no need to rush into irreversible decisions like that as quickly as possible.
• The same principle should be used generally - an open ended approach which keeps future options open. We are not yet at the point where we have enough understanding to close down on future possibilities by doing actions with irreversible consequences.
• In this approach, planetary protection and biological reversibility are core principles. This does not mean that we can never send humans to the Mars surface. That's for future discussion once we have a better understanding of ourselves and of our solar system. It is impossible at this stage to even know for sure what the issues will be by the time we might need to make that decision, which on this vision would be at least some decades into the future (you need time to explore Mars reasonably thoroughly first). Meanwhile we have many exciting places for them to explore, including exploring Mars itself via telepresence - and many other exciting experiments in human settlement to try closer to hand.

For the vision in full with details, see my "Case For Moon - New Positive Future For Humans In Space - Open Ended With Planetary Protection At Its Heart". 

FACEBOOK GROUP

I've made a new facebook group which you can join to discuss this and other visions for human exploration with planetary protection and biological reversibility as core principles. Case for Moon for Humans - Open Ended with Planetary Protection at its Core