Actually - it's more that the moisture of your eyes would boil, blood won't boil because it's contained in your veins and arteries.
The Armstrong limit is a tenth of Earth normal. You can read the effects here:
Armstrong limit
The Mars atmosphere at the bottom of the Hellas basin is 1% of Earth normal so a tenth of the Armstrong limit so well beyond that limit. Pretty close to the vacuum of space for all intents and purposes as far as a human is concerned.
Hellas Planitia
In any case you would want to spend as little time in your spacesuit as possible - because there is no way to protect a spacesuit from cosmic radiation - and who wants to add a several percent risk of dying of cancer and reducing your life span by a decade or more? And even best spacesuits are likely to be clumsy, and if you damage it you are dead, so if you want to do e.g. heavy earth moving you'd use a bulldozer of some type and surely operate that from inside the habitat not go out and sit on it.
An accident with heavy machinery, which on Earth would mean just a cut or a graze, would kill you on Mars within seconds.
But - personally as you'll see from my other answers, I don't see the point in sending humans to the surface, because they will only greatly increase the risk of introducing Earth life to the planet.
And a study (the HERRO study) has shown that a mission to orbit around Mars could do three times the amount of work of a surface mission, by exploring via telerobotics - than a mission to the surface. That's taking account of the extra time it takes to suit up etc. Plus ease of operating telerobotics in shirt sleeves environment and have three or more robotic "bases" on the surface which you can control and jump from one to another and leave the robots in the other bases busy doing whatever it is they are doing, and with several crew able to operate several bases at once.
They would go to a Mars capture orbit - one that's optimized for telerobotics - a slowly sun precessing Molniya orbit with several hours of close up telepresence every 12 hours over opposite sides of Mars each time. So the delta v is the same, to all intents and purposes as a Mars surface using aerobraking. But without the dangerous descent to Mars and without the expense of developing human rated landing equipment -I think pretty clear it would cost less than a surface mission.
This simulates the orbit they would use - in orbiter. I use a futuristic spacecraft as that was the easiest way to do it. Apart from that, it is the same as the orbit suggested for HERRO.
It would be a spectacular orbit and a tremendously humanly interesting and exciting mission to explore Mars this way.
That study was done some years back, and I think telerobotics is advancing more rapidly than spacesuit capabilities so chances are that it would show even more of an advantage now.
Main reason it is so slow at present is the long time lag from Earth so that a rover on Mars is - e.g. Opportunity travels over the surface of Mars at perhaps (not done detailed calc yet) a twentieth of the speed of the Russian 1970s Lunakhod operated from Earth - still hasn't quite traveled as far as Lunakhod traveled in a few months.
Modern rovers operated by telerobotics from orbit could probably travel at almost the same speeds as on Earth Probably cover more ground than the Apollo 17 per day - as they only operated for a few hours a day - and were restricted by the need to never travel so far from base that you can't walk back again with your available air supply (same restrictions would probably apply on Mars).
Probably a modern rover driven on Mars by telerobotics, with battery motors equal to the Apollo 17 lunar buggy, could do the entire Opportunity journey in a single day, seems to me. And you could use either fuel created on the surface - or a large area of light weight thin film solar panels spread out over the surface of Mars, to charge it up and repeat the performance day after day.
Far more traveling for less cost than human surface missions as you are not restricted to area around base or need to carry oxygen with you -and indeed if you find somewhere interesting - can simply just leave the rover there for months doing its analysis.
Similarly for sample analysis etc far far faster by telerobotics than for our robotic missions, but no obvious advantage over humans on the surface, not with good haptic feedback and binocular vision etc.
And far safer, no need for risky landing on Mars, and no risk of damage to spacesuit killing you etc.
Personally I find it extraordinary that NASA is still considering sending humans to the Mars surface. It has no scientific rationale as far as I can see. Not if you do a detailed comparison with telerobotic exploration.
Some people say that you need humans to drill. But drilling in a spacesuit is going to be very clumsy. And ExoMars will drill to 2 meters depth without humans - and future rovers will be able to drill kilometers using robotic moles.
Similarly also for exploring cave and cliffs - robots can rapel, and be designed to explore caves and climb steep slopes and go over rugged terrain - so far we haven't sent those types of robots to Mars - but they do exist and could be made space hardy and sent there - there are several projects looking into it. While humans again major safety issue, if you are trapped or have an accident, you die. If a robot is trapped, worst thing happens is you have to send another robot.
And even if humans were better at some thing than robots, well what's the point if you contaminate Mars in the process?
I've not seen any other paper comparing telerobotics to a human mission on the surface except the HERRO one - which concluded strongly in favour of the telerobotic mission.
So I don't think NASA can possibly have made that decision based on a scientific comparison of a surface mission with a telerobotic orbital mission. Not seen any working group or study looking into it and comparing the two options for their science value, apart from that HERRO study some years back - and the Telerobotics conference a couple of years back - they didn't do a direct comparison, just said that if we send an orbital mission to Mars it would be a major missed opportunity not to use it for telerobotic exploration of Mars.
As far as the NASA plans are concerned, I think it is just a political thing, like sending humans to the ISS or sending the Apollo astronauts to the Moon.
And unlike those two - is not just more expensive for the same science return as a science lead mission. It also greatly increases risk of contaminating Mars with Earth life. Near certainty if you have a crash landing on Mars.
On Mars with telerobotics - you can explore the surface - in a way that is better, and more fun, than being there on the surface. Using the likes of the Occulus Rift, and haptic feedback, and the Virtuix Omni - you can have a fully immersive experience of being on the surface of Mars.
Far better than actually being there, as we wouldn't be able to see well in the dark reddish light - can't see colours, everything is a muddy dirty brown to human eyes if you look at the original unprocessed raw images.
And far more agile without spacesuits. Just a rover with binocular vision, and hands you can use to explore things.
And whole thing streamed back live to Earth as well, so with just a few people exploring Mars via telepresence, entire Earth can take part, and see what they see and feel what they feel..
I think telerobotics can easily be made to cater for this aspect of humanity - indeed more interesting than a surface base.
We have places on the Earth that are quarantined. Many places quarantined from higher animals - we don't always succeed but for instance, managed to keep rabbits, rats etc away from many islands where they would be devastating.
Managed to keep Antarctica relatively free of non indigenous microbes - it is one of the few places where microbes can be invasive on Earth.
It can be done. Especially since naturally insulated by the vacuum of space.
Yes life might have been shared - but that's not been proved either way - and if it has - probably at least tens of millions and probably more likely billions of years ago it happened - so Mars life - may be some of it has common ancestor to Earth life. Could be none has, could be a mix of some that has - and whatever - likely to have evolved a lot since that common ancestor if there was one. And on Earth also.
Whatever you might think of that - it's current space policy to protect Mars from Earth life. And - personally I think it would be a tragedy to contaminate it with Earth microbes - especially if done before we have a chance to study it.
It is after all also, NASA's main reason for going to Mars - to search for life there.
The main difference between now and six years ago - when it made more sense to send humans to the surface - is that we now think that there may well be widespread habitats on the surface of Mars that life can inhabit.
Many scientists have said this recently, and this is one of the most and up beat statements about the prospect of present day life on Mars in the media recently:
For earlier work see for instance the The Present-Day Habitability of Mars 2013
If Earth life can survive on Mars - on the surface - almost anywhere in small patches on Mars - that of course greatly increases the need to take care not to contaminate it when you explore Mars.
Though it hasn't yet hit headline news, as it were, you do get news articles from time to time about this contamination issue for human landings on Mars.
It's been discussed in the scientific literature for decades.
The Armstrong limit is a tenth of Earth normal. You can read the effects here:
Armstrong limit
The Mars atmosphere at the bottom of the Hellas basin is 1% of Earth normal so a tenth of the Armstrong limit so well beyond that limit. Pretty close to the vacuum of space for all intents and purposes as far as a human is concerned.
Hellas Planitia
In any case you would want to spend as little time in your spacesuit as possible - because there is no way to protect a spacesuit from cosmic radiation - and who wants to add a several percent risk of dying of cancer and reducing your life span by a decade or more? And even best spacesuits are likely to be clumsy, and if you damage it you are dead, so if you want to do e.g. heavy earth moving you'd use a bulldozer of some type and surely operate that from inside the habitat not go out and sit on it.
An accident with heavy machinery, which on Earth would mean just a cut or a graze, would kill you on Mars within seconds.
But - personally as you'll see from my other answers, I don't see the point in sending humans to the surface, because they will only greatly increase the risk of introducing Earth life to the planet.
MISSION IN ORBIT TO DO THREE TIMES THE AMOUNT OF SCIENCE EXPLORATION FOR FAR LESS COST THAN ONE SURFACE MISSION
And a study (the HERRO study) has shown that a mission to orbit around Mars could do three times the amount of work of a surface mission, by exploring via telerobotics - than a mission to the surface. That's taking account of the extra time it takes to suit up etc. Plus ease of operating telerobotics in shirt sleeves environment and have three or more robotic "bases" on the surface which you can control and jump from one to another and leave the robots in the other bases busy doing whatever it is they are doing, and with several crew able to operate several bases at once.
They would go to a Mars capture orbit - one that's optimized for telerobotics - a slowly sun precessing Molniya orbit with several hours of close up telepresence every 12 hours over opposite sides of Mars each time. So the delta v is the same, to all intents and purposes as a Mars surface using aerobraking. But without the dangerous descent to Mars and without the expense of developing human rated landing equipment -I think pretty clear it would cost less than a surface mission.
This simulates the orbit they would use - in orbiter. I use a futuristic spacecraft as that was the easiest way to do it. Apart from that, it is the same as the orbit suggested for HERRO.
It would be a spectacular orbit and a tremendously humanly interesting and exciting mission to explore Mars this way.
That study was done some years back, and I think telerobotics is advancing more rapidly than spacesuit capabilities so chances are that it would show even more of an advantage now.
Main reason it is so slow at present is the long time lag from Earth so that a rover on Mars is - e.g. Opportunity travels over the surface of Mars at perhaps (not done detailed calc yet) a twentieth of the speed of the Russian 1970s Lunakhod operated from Earth - still hasn't quite traveled as far as Lunakhod traveled in a few months.
Modern rovers operated by telerobotics from orbit could probably travel at almost the same speeds as on Earth Probably cover more ground than the Apollo 17 per day - as they only operated for a few hours a day - and were restricted by the need to never travel so far from base that you can't walk back again with your available air supply (same restrictions would probably apply on Mars).
MODERN ROVER DO ENTIRE OPPORTUNITY DRIVE IN A SINGLE DAY BY TELEROBOTICS
Probably a modern rover driven on Mars by telerobotics, with battery motors equal to the Apollo 17 lunar buggy, could do the entire Opportunity journey in a single day, seems to me. And you could use either fuel created on the surface - or a large area of light weight thin film solar panels spread out over the surface of Mars, to charge it up and repeat the performance day after day.
Far more traveling for less cost than human surface missions as you are not restricted to area around base or need to carry oxygen with you -and indeed if you find somewhere interesting - can simply just leave the rover there for months doing its analysis.
Similarly for sample analysis etc far far faster by telerobotics than for our robotic missions, but no obvious advantage over humans on the surface, not with good haptic feedback and binocular vision etc.
And far safer, no need for risky landing on Mars, and no risk of damage to spacesuit killing you etc.
WHY DOES NASA HAVE HUMAN LANDING STILL AS AN OBJECTIVE?
Personally I find it extraordinary that NASA is still considering sending humans to the Mars surface. It has no scientific rationale as far as I can see. Not if you do a detailed comparison with telerobotic exploration.
Some people say that you need humans to drill. But drilling in a spacesuit is going to be very clumsy. And ExoMars will drill to 2 meters depth without humans - and future rovers will be able to drill kilometers using robotic moles.
Similarly also for exploring cave and cliffs - robots can rapel, and be designed to explore caves and climb steep slopes and go over rugged terrain - so far we haven't sent those types of robots to Mars - but they do exist and could be made space hardy and sent there - there are several projects looking into it. While humans again major safety issue, if you are trapped or have an accident, you die. If a robot is trapped, worst thing happens is you have to send another robot.
And even if humans were better at some thing than robots, well what's the point if you contaminate Mars in the process?
I've not seen any other paper comparing telerobotics to a human mission on the surface except the HERRO one - which concluded strongly in favour of the telerobotic mission.
So I don't think NASA can possibly have made that decision based on a scientific comparison of a surface mission with a telerobotic orbital mission. Not seen any working group or study looking into it and comparing the two options for their science value, apart from that HERRO study some years back - and the Telerobotics conference a couple of years back - they didn't do a direct comparison, just said that if we send an orbital mission to Mars it would be a major missed opportunity not to use it for telerobotic exploration of Mars.
As far as the NASA plans are concerned, I think it is just a political thing, like sending humans to the ISS or sending the Apollo astronauts to the Moon.
And unlike those two - is not just more expensive for the same science return as a science lead mission. It also greatly increases risk of contaminating Mars with Earth life. Near certainty if you have a crash landing on Mars.
EXCITEMENT AND HUMAN INTEREST OF EXPLORING THE SURFACE DIRECTLY
On Mars with telerobotics - you can explore the surface - in a way that is better, and more fun, than being there on the surface. Using the likes of the Occulus Rift, and haptic feedback, and the Virtuix Omni - you can have a fully immersive experience of being on the surface of Mars.
Far better than actually being there, as we wouldn't be able to see well in the dark reddish light - can't see colours, everything is a muddy dirty brown to human eyes if you look at the original unprocessed raw images.
And far more agile without spacesuits. Just a rover with binocular vision, and hands you can use to explore things.
And whole thing streamed back live to Earth as well, so with just a few people exploring Mars via telepresence, entire Earth can take part, and see what they see and feel what they feel..
I think telerobotics can easily be made to cater for this aspect of humanity - indeed more interesting than a surface base.
PRACTICALITY OF KEEPING MARS FREE OF EARTH LIFE
We have places on the Earth that are quarantined. Many places quarantined from higher animals - we don't always succeed but for instance, managed to keep rabbits, rats etc away from many islands where they would be devastating.
Managed to keep Antarctica relatively free of non indigenous microbes - it is one of the few places where microbes can be invasive on Earth.
It can be done. Especially since naturally insulated by the vacuum of space.
Yes life might have been shared - but that's not been proved either way - and if it has - probably at least tens of millions and probably more likely billions of years ago it happened - so Mars life - may be some of it has common ancestor to Earth life. Could be none has, could be a mix of some that has - and whatever - likely to have evolved a lot since that common ancestor if there was one. And on Earth also.
Whatever you might think of that - it's current space policy to protect Mars from Earth life. And - personally I think it would be a tragedy to contaminate it with Earth microbes - especially if done before we have a chance to study it.
It is after all also, NASA's main reason for going to Mars - to search for life there.
WHY MANY THINK MARS SURFACE CAN BE CONTAMINATED NOW - AND MOST PEOPLE DIDN'T THINK SO, SIX YEARS AGO
The main difference between now and six years ago - when it made more sense to send humans to the surface - is that we now think that there may well be widespread habitats on the surface of Mars that life can inhabit.
Many scientists have said this recently, and this is one of the most and up beat statements about the prospect of present day life on Mars in the media recently:
"Based on the results of our experiment, we expect this soft ice that can liquify perhaps a few days per year, perhaps a few hours a day, almost anywhere on Mars. So going from mid lattitudes all the way to the polar regions. This is a small amount of liquid water. But for a bacteria, that would be a huge swimming pool - a little droplet of water is a huge amount of water for a bacteria.That's Nilton Renno, a professor of atmospheric, oceanic and space sciences at Michigan University who lead the research. See also Martian salts must touch ice to make liquid water, study shows
So, a small amount of water is enough for you to be able to create conditions for Mars to be habitable today'. And we believe this is possible in the shallow subsurface, and even the surface of the Mars polar region for a few hours per day during the spring." (transcript from 2 minutes into the video onwards)
For earlier work see for instance the The Present-Day Habitability of Mars 2013
If Earth life can survive on Mars - on the surface - almost anywhere in small patches on Mars - that of course greatly increases the need to take care not to contaminate it when you explore Mars.
Though it hasn't yet hit headline news, as it were, you do get news articles from time to time about this contamination issue for human landings on Mars.
It's been discussed in the scientific literature for decades.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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