I’m not sure about you, but I’ve never had junk food literally rammed down my throat.
[QUOTE=Xema]
I’d find it hard to say why these tasks would be impossible - or even notably difficult - to a robotic probe well within current technology. In particular, the Mars rovers definitely spotted interesting things and then checked them out.
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Makes sense, except that something even close to as flexible as a human astronaut hasn’t been built yet, nor am I aware of anything on the horizon that will change that or even come close.
Sure, the Mars rovers have been able to stop and check some things out in a very limited way when the operator or someone reviewing video saw something. However, as the link I showed demonstrates, it’s been operating for over 10 years and hasn’t managed to cover the territory that the Apollo 17 astronauts covered in 22 hours (much of which wasn’t spent doing exploration).
As folks noted (though I think the $250 billion is out of the ball park for an actual manned Mars mission today) a manned mission would cost a lot more than each individual rover mission. But a single Mars mission would be the equivalent of decades if not centuries of rover missions. Even assuming large leaps in the future for rover technology (which I think is a viable bet), putting all of that together and getting it successfully to Mars is going to take a lot of time since windows to launch to Mars only open up every few years and the costs per mission seem to be increasing, not decreasing as we get more complexity and value add into each mission.
Like I said, this is more a debate (and one we’ve debated on this board seemingly endless times) than a GQ type question, since it boils down to folks who think human exploration is a waste and that rovers can do it all (or that there is nothing worth seeing on Mars, or several other similar positions) and those who think that we are at the stage now where human exploration is going to get us to the next level of really understanding Mars (or just think human exploration is cool or has other benefits beyond scientific exploration). Personally, I think that sending a geologist to Mars with a lab will yield more real science in the first month than we have gotten in the past 2 decades on the surface, and that the challenge of doing it will give us more bang for our buck than any number of robotic missions. Which isn’t to say we should stop doing robotic missions of course, since they have been and probably will remain the only option until we get off the dime (or some other nation or group of nations decide they are going to do it instead).
According to the link I posted, it looks like the PRC did sign the treaty, 30~some years ago.
There was a microphone aboard Huygens, which landed on a moon of Saturn named Titan.
Here’s the .mp3: http://esamultimedia.esa.int/images/huygens_alien_winds_descent.mp3
There’s also video footage of its descent:
With reference to** XT** saying :- “It will be a lot more dangerous, obviously, and will cost a hell of a lot more”
I actually think it would be cheaper in the long run the one thing a human is that Machines are not is adaptable so if you send the correct people then you would not need to have so many different types of gadget and gizmo to conduct several different experiments.
Also the prospect of being the first or one of the select few that make the trip if they survive and return then they are made for life. Think about Neil Armstrong “That’s one small step for a man, one giant leap for mankind.” one line and he could dine out for the rest of his life for free if he so wished. That was back in 1969 imagine now a days advertising sponsorship and basic freebee opportunities… The first person to Mars or people in that team wouldn’t need to worry about buying cars second hand I assure you.
But in my view its not should we send people rather than machines, but more a question of who we should send first taking the risks. My personal preference would be people that id prefer as far away as possible so maybe all politicians 
no that wouldn’t work because if trip was a success they incapable of doing a days graft so be a total waste of time. But my personal request is making up the team if there is one spare seat could we fit Rupert Murdoch in, just for a one way trip to just see how long someone could survive on the planet that would benefit mankind in all sorts of ways I think, he could set up a universal news network from there to feel at home.
The whole idea of flexibility of a human on Mars doesn’t address the goals of the mission.
Clearly if we are comparing robotic to human missions the only mission goal is scientific exploration. Not much point sending robots out to colonise.
The Apollo astronauts didn’t do much science on the moon. They did a lot of data gathering. The science was done when they got back. They were trained to recognise different rocks and knew what was worth picking up. They didn’t come back and tell everyone the geological history of the moon. That was done in labs on the Earth. Something not mentioned much - most of the Apollo lunar samples have never been analysed. They brought back far more rock than was actually needed.
The biggest problem with a manned mission to Mars is that during its duration, most of the science won’t be done. The science won’t be done on the surface of Mars, and the results won’t be known or understood for some time. So many of the follow-up experiments won’t be specified until the mission is over. You will have a one shot data gathering expedition, that looks for stuff based upon a limited set of knowledge, and only able to plan things based upon short term cursory analysis of what they find. Most of the science won’t be directly done by humans anyway. The Mars mission astronauts will be carrying about lots of high tech kit to analyse what they find. Most of it will be seriously automated and will send the results back to scientists on the Earth. They will tell the astronauts what to look for next. Productivity will be higher - but science for the dollar - substantially less. And worse - no ability to follow-up science results that become known after the mission is over.
A long term mission - many years - with resupply including new equipment is what would be needed. An ISS on Mars. But the science for the dollar just isn’t going to be there.
A continual stream of robotic landers, each designed to follow-up science from the last, with a range or overlapping goals will get you more science for less money.
[QUOTE=Francis Vaughan]
The Apollo astronauts didn’t do much science on the moon. They did a lot of data gathering. The science was done when they got back. They were trained to recognise different rocks and knew what was worth picking up. They didn’t come back and tell everyone the geological history of the moon. That was done in labs on the Earth. Something not mentioned much - most of the Apollo lunar samples have never been analysed. They brought back far more rock than was actually needed.
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That’s because they only had a VERY limited time on the moon, not because it’s inherently impossible to do science in situ.
All of the missions I’ve seen planned have scientific labs on them, and the plan is to send scientists as well as astronauts, so this simply doesn’t have to be the case. In fact, it would be crazy to have the astronauts on Mars for over a year just collecting data and do nothing with it until they get back. How does that even make sense to you??
Why? 
Any mission to Mars is going to be long term. Right now they are talking 2 year missions, with 6 months in transit and a year on the planet. Science will absolutely be there. I get the feeling you are under the impression that a Mars mission would be a foot prints and flags thing where the astronauts are there a couple of days then head back. Doesn’t work that way. Even the (more dangerous) fast return trip would have the astronauts on the planet for 2 months…and this is the least likely mission profile.
I disagree.
Sending a million robots to Mars only tells us about that one particular planet. The purpose of sending humans to Mars is the doubling of the number of planets we can survive on. And once we’ve learned to survive there, we will have learned to survive on thousands of other planets. All we need to learn is how to get there.
What I wrote was mostly to disagree with the fast agile human beats robotic notion. Sure with unlimited funds you can send up a huge amount of scientific gear. But every time we do we add many billions to the cost. Scientific labs? Sure - how many tons of gear do we envision? How much in consumables, and what range of science do we think the humans can do? I would contend that a robotic sample return mission will beat any human outpost on science for the dollar trivially.
The problem is we don’t know what the big finds will be. Or where. Everyone is worried about the possibility of life. What if there is none? What are the other science goals? What level of gear do you need to send to do stuff?
It would be nice to do seismic surveys. Also high resolution mag and grav. (We only have very low resolution satellite stuff.) None of that needs humans. Certainly not to analyse the data. Drill samples and eventually sample return will provide huge amounts of data.
I have always assumed a roughly one year on the ground mission - hit the transfer windows on the way up, and then on the way back. One year is not a lot of time. When their time is costing a billion dollars a day, you would want a very good story about how productive they are being. Say you have three scientists on the surface. Their time is costing about a Curiosity rover every day. No matter what, on the surface scientists will be glorified data gatherers and lab technicians. And their scientific value in dollars for the science done will be dreadful.
Are you aware that the cost difference is so vast that you really can send hundreds, possibly thousands of separate robot landers for every manned mission? The thing is, current robot landers are one offs. If we were spending the same money a manned mission would cost on robot probes instead, we’d mass produce them, where every robot is identical except for a modular instrument package that would be changed out each mission.
Losing a certain percentage of them on launch, landing, or in the first few months would be considered acceptable. (since it would be more expensive to build the robots to such a high level of quality that wouldn’t happen)
I was talking to a retired NASA Engineer on the Mars program and his involvement and comments
It was a long presentation but I will try to summarize some of the points
- Before going to Mars, NASA wants to return to the Moon. Remember that it has been 43 years since the last moon landing and a lot (most) of the people involved with that have been retired or are dead. So even though the technology is there, the actual real experience for a moon landing is not and that counts for a lot.
Once back on the moon, that experience would make a manned Mars landing somewhat easier although still very difficult
- With the moon landing, the bulk of the controls and monitors for Apollo where actually in Mission control in Houston and not on Apollo. The sensors and controls were on Apollo but they were being monitored and mostly controlled by mission control. A prime example is the fuel count down when the Eagle was landing. That was being monitored by ground control, not Neil Armstrong who was piloting the ship although he was verbally getting the information.
His emphasis was on the landing, not watching the fuel gauge.
The distance from Earth to the moon meant that there could be a feedback loop to allow this in real time (There was a few seconds delay but that was not critical)
With a Mars trip, the time for communications to get back and forth would be too long to allow for this instantaneous control from mission control and that is where a human could allow for real time intervention than a unmanned missions could not have. (Don’t remember the numbers off hand but it was 20- 30 minutes for a round trip signal)
True, the unmanned missions with more powerful computers and additional programming that has developed since them could anticipate many more problems but there is a good chance that something unforeseen could happen. Again the prime example is when Neil Armstrong changed his landing position because he thought it was too rough to land on.
- A major issue with the Mars trip is the length of time it takes to get there.
There are 2 additional problems from this
One is the long time in zero G. There has not been extensive studies with long times with humans in zero G. There are some but the longest I think was about a year or so. Some humans systems come back to normal after some time in zero G but I believe one of the things that does not some back is the bone loss (even with heavy exercise, good diet and calcium supplements)
Two is the exposure to radiation. It was estimated that there was roughly a 1- 2 % chance of death due to radiation exposure over the mission, not insignificant by any means. And probably some radiation sickness or an increased potential for cancer from this.
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To build the manned mars ship requires a new Booster (Ares 5) which is the Saturn 5 on Steroids to put it in simple terms. And even with that, I think it would take several missions just to get the ship together as the final assembly has to be in orbit.
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He did not have time to cover the social implications of having the crew together for such long period of times. It has been done on the ISS for long period of times so it should be possible but there is always the possibility that someone could go berserk on the mission. At least with the ISS, there is the ability to get someone down back to Earth. Not so with this.
Even with Submarines, (which is a similar situation) they do surface and do get to port every so often so this would be another unknown
- He did not cover as to any medical problems that may arise. Of course, the people chosen would be fairly physical fit but there is always the possibility that something could develop during the trip and the medical capabilities on board would not cover much more than the basics. (i.e. I can’t see there being a MRI on board - but I could be wrong) and certainly anything more than just basic surgery would be difficult.
His final point was that the manned missions would be a supplement to the unmanned missions and he felt that NASA needed more money that their current budget has to pull this off as space exploration is not cheap and costs go into the billions very quickly especially for manned missions
The dates he estimated were 2018 - 2020 for return to the moon and 2038 - 2040 for going to the Mars
Even if that’s true, a manned Mars mission would also cost the equivalent of centuries of rover missions. NASA has been spending about $1.5 billion per year on planetary science - that’s all planets, not just Mars. If Mars is half of that, and if we assume a manned mission to Mars costs $150 billion, that’s literally the cost of 200 years of unmanned Mars missions.
There’s no reason robotic missions should or would be restricted to Mars.
You don’t go to a planet to learn to survive there - any hope of a successful mission absolutely requires that you have carefully worked out how to survive before you go.
And never mind thousands - where are even a couple of additional planets that we could successfully visit and survive on? Nothing we encounter on Mars will teach us much about surviving on Mercury, Venus, Jupiter or Saturn.
If you’re talking about places outside our solar system, the answer to “how to get there” includes “wait until some new aspects of fundamental physics are discovered”.
Significantly, he did not so wish - he remained a modest, low-eqo guy his entire life.
A couple of mistakes when quoting the presentation from the retired NASA engineer as he had some old slides that were not updated
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It is not ARE5 but the SLS (Space Launch System) that would be used. Similar concept of a heavy booster but significantly different designs
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The return to the moon by 2020 was cancelled and they are going to an asteroid by and back 2025. This would also be a good test bed for the Mars mission although I think a return to the moon would also be a good test bed as well for many of the Mars concepts
This would be a valid point (aside from having to wait a century or so for results) except that we aren’t sending robotic probes nearly as often…more like a probe every 10 years which kind of stretches out the time . In addition, as we require probes with more complexity they will cost more and more.
The Mars Direct mission was slated at $20 billion dollars. I think that’s way under what it would actually cost. A more realistic price might be $80-100 billion, even with the follow on missions slated. A lot of the costs that were being factored into a Mars mission had to do with the cost of a new manned launch system…costs that are sunk at this point, since NASA has already been developing that system.
[QUOTE=Habeed]
Are you aware that the cost difference is so vast that you really can send hundreds, possibly thousands of separate robot landers for every manned mission? The thing is, current robot landers are one offs. If we were spending the same money a manned mission would cost on robot probes instead, we’d mass produce them, where every robot is identical except for a modular instrument package that would be changed out each mission.
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You could send hundreds, not thousands, and yes I’m aware. I’m also aware that we won’t send hundreds of probes to Mars, realistically, and that the ones we send will be one offs. And I’m aware that even if we DID send hundreds of probes to Mars (something we aren’t going to do), it would take decades or centuries to get them all over there and thus decades or centuries before we got the value we’d get out of one manned mission. That’s the thing…in order to say there is no reason to send humans because robots can do it all you have to posit that we’d send hundreds of probes like the ones we’ve previously sent (but more advanced yet cost the same) and we’d do it over decades or centuries. Sure…if we assume all of that then sure, no reason to send humans and we can do it all with probes! Realistically, however, we aren’t going to do that. Eventually, some nation is going to send humans to Mars.
You might want to check this out when figuring the percentage of robotic missions that actually make it to Mars and do something.
One thing to consider.
If we send a manned mission(s), they will be the mother of return sample missions. When you look at all the mass it takes to send humans to mars and back, hell a few tons of rock samples coming back as well is probably in the noise additional cost wise.
Also, actual humans on the surface figuring out which rocks look good and which don’t probably increases productivity per time on the surface several orders of magnitude over a probe.
Interesting stuff, thanks
Descent fuel usage is very critical for landing on the moon. I had a game on my HP33 calculator where you had to try to balance fuel consumption with speed and try not to run out or crash. Mars has atmosphere, which cuts both ways: you have to have heat shielding, which makes you blind for a minute or two, but later, you can use a chute or wings for braking. So, it is kind of a whole new bag of worms, and you have to be absolutely certain you are not going to drop everyone into a chasm where it would be a pain to get out.
It looks like the round-trip at the time of arrival would be at least 35 minutes. But, of course, computer power and capacity has increased by over 20 Moores since Apollo, by the time we could get to a Mars trip, they should be able to have a five or six compact Big Blue quality machines onboard, so Mission Control would be more like Mission Advisors. By the time they are actually ready to land, Mars and Earth would be 30~40° past conjunction, which might be as much as 40 minutes of signal travel time.
Spin the damn ship. Fast. It should not be that hard to set up.
The astronauts will need a large water supply: jacket the crew space with their water, it makes for a pretty effective radiation absorber.
Beyond that, mission prep would involve sending at least half a dozen supply barges to Mars orbit. Triple-redundancy would be preferable, as you would not want the mission to arrive and not have enough stuff to make it worthwhile. Docking in orbit is probably a more reliable strategy than trying to land close to a thing on the ground, and the barges would also carry some study instrumentation, and perhaps a robotic lander or two, along with the capability of being dropped close to the mission, if more stuff is needed.
Which could turn out to be one of the bigger benefits to the mission: learning about how people can get along with each other. One of the bigger issues has to be occultation – the two or three months that the mission will be completely out of communication with Earth while on the other side of the sun. How they get through that has to yield some pretty interesting social study data.
Given how absurdly easy and cheap it would be to learn about this from experiments on Earth, I’m amazed how often this gets cited as one of the big benefits of a manned Mars mission.
Indeed, the idea of sending a (hideously expensive and already rather risky) mission to Mars without having spent serious effort investigating what can be learned on Earth seems spectacularly irresponsible.
Great points a few comments of my own.
Aside from 2001 and 2010 movies, I have not seen it tried to spin the ship for artificial gravity.
I am surprised that this has not been tried in LEO (yet) but they may have not been a large enough vehicle to try this and I am sure that it has been proposed
Another thing about the spinning. Spinning creates heat from friction. Yes, they would be using lubrication and bearings but could the lubrication last for the entire trip or would it need to be replaced?
That might be a little more difficult in space than on the ground.
Yes, the large water supply would help shield from radiation. However, water protects very well from alpha and beta and neutrons. However, it struggles with gamma and x-ray radiation unless a lot of water is used for shielding which then makes the craft bigger.
Not saying that any of this is impossible but sometimes things that seems easy in concept are much more difficult in reality.
Thanks for your response