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Staying on Terra Firma
For many years, a main goal of NASA has been to send a man humans to Mars. In fact, it seemed right after the moon landings to be the next logical step in space exploration. I was a youngster when the Gemini and Apollo missions were big news. I watched the first moon landing live on television. I remember the drama of Apollo 13 (as well as the movie).
I watched the original Star Trek series when it first aired, and went to the movie theater twice to watch Star Wars when it was first released. It seemed like anything was possible. We were going to invent Warp Drive and go faster than the speed of light! The universe was ours to explore!
But it’s not. We are not going to the stars. The distances are much too great. We might be able to send people to Mars, but the other planets are very unlikely destinations. They are too far and if we could get to them we would find that the environments we would encounter would make it impossible for us to visit much less live – even with technology we could possibly develop.
We have picked Mars because it is one of two “close” planets. Venus has a poisonous atmosphere so that is out of the question. And we have always had a much greater fascination with Mars (the god of war) than with Venus even though Venus is ‘hotter’. (Pun intended.) But Mars is not that hospitable either. It has little or no atmosphere and its gravity is too small to hold any kind of atmosphere we could live on much less to grow crops on. So we would have to take both air and food to Mars, enough to sustain the crew through the trip. (Building some kind of colony seems impossible.) That would take an enormous payload. The rocket ship would be huge and extremely expensive.
There is another possibility, I am told, and that is to grow the food on the ship. What else does the crew have to do but grow stuff during a months-long trip? This is not a quick trip to the moon. It would be a huge, extremely expensive expedition. And it would be far too dangerous for anyone to make. It would be unwise for the bravest, even the ones with “the right stuff”. There are risks worth taking and there are foolish risks. This falls into the latter category.
I know that NASA scientists know all about the dangers. The reason that I know is that I personally know a few of them myself. There is a NASA base about five miles from here. Two of them have done work for the Space Station. They all seemed convinced that people will make it to Mars someday. But what they cannot tell me is why we would want to go. Some speak of the fact that we would gain scientific knowledge. Others say that we would benefit greatly from the technology developed to make the trip. About the former, I would agree, but would the expense outweigh the possible gains?
I think that whatever gains we might get from persons traveling to Mars would be much less than even just the financial outlay. I especially do not think that the gains would be worth the risk to human life. I am not a snowflake. I know that great progress comes at great expense and often the cost of many human lives. I am not completely risk-averse. But the cost must not outweigh the gains. In other words, the cost/benefit analysis, if it can be done, seems to tell us that there is no good reason for humans to go to Mars. A lot of the knowledge that might be gained we can get by sending instruments and robots to Mars to find out what we can. And I am not saying that we shouldn’t do that.
Additionally, there is the opportunity cost of such a quest. We really need our best scientists to work on other things at home to make life on earth better. I would rather have them in other research or private industry to increase the living standards not only for us but for the developing world. Science has given us a tremendous amount already, but this pandemic has shown us that there is much more to do. Let’s concentrate on continuing our progress here on earth and not waste resources on a not-very-fruitful but fascinating goal. I think we ought to get our heads out of the clouds and realize that science fiction can be entertaining, but it is not realistic. We are here on earth and we are staying here. I have not mentioned religion yet, but I must. As a Christian, I know that God made this earth for us to live on and to have dominion over. He did not give us Mars to live on. He did not give us the moon to live on. He gave us the earth. Let’s stay on it.
[I am sure that my Ricochet friends will correct any errors of scientific fact, but I do not think that it will change my thesis.]
Published in Technology
If we were able to launch an Apollo-speed mission to Mars at closest approach, it should take about 6 months. But that only happens once about every two years.
And on an Earth-Moon flight, the Earth is never any farther from the Moon than on any other day. But for an Earth-Mars flight, it’s very different. You’d be aiming for where Mars WILL BE once you get there. Six months ahead, Mars would be over 200 million miles away from the eventual rendezvous point. And in six months, Earth would be about 300 million miles along in its orbit. (About 1.6 million miles per day.)
With the gap widening like that, even if there was some emergency and they wanted to turn around and return to Earth, they probably couldn’t.
The difficulties are of an entirely different level and nature, which I’ve been trying to point out, apparently without success.
First of, we agree, going to Mars is difficult – much more difficult than going to the Moon. I think the technology exists to do it. (or at least mostly does) The challenge of going to Mars is engineering not technology development. The real difficulty is developing the heavy lift capability to lift the mission to LEO and beyond.
Dr Zubrin seems to think that a 40 ton payload to Exit velocity would be sufficient to put a small crew on Mars. (provided there are already supplies there – and a fully fueled return vehicle waiting)
Correct – an emergency in route will not be able to turn back – the free return trajectory would return the vehicle 2 years after it left earth.
I think it’s far more likely that there will be no return capability, neither brought along nor pre-positioned. Many people will still volunteer, but it should be made somehow iron-clad that there can be no lawsuits etc as a result. Which is why I previously suggested that all the volunteers should have no relatives left behind on Earth, who might be tempted or even bribed into claiming “damages.”
The free return trajectory is the 6 month trip to Mars. If for some reason you dont retro fire to brake to enter Mars orbit – you return back to earth – 2 years after you left. Its a free return trajectory – its was used during the Apollo era – and its the reason that Apollo 13 returned to earth.
Yes but we’re talking about a 6-month trip turning into 2 years, versus a ~3-day trip to the moon and 3 days back which was always planned for in terms of supplies etc. Having enough supplies on a Mars ship to last 2 years rather than 6 months is a big difference, even if much of it would have been brought anyway to support the “base” they set up.
Ship systems would also have to be a lot more durable, and if supplies like water are also being used for radiation shielding, they would be depleted by the return to Earth and the people would have been exposed to radiation way before then.
And for a possible 2-year trip, some kind of gravity rotation becomes less optional/desirable and more mandatory. People coming back to Earth after TWO YEARS in basically zero gravity, would have serious problems.
True they would IF they didnt do the daily exercises to maintain muscle mass. (bone mass is a different kettle of fish)… The water mas for shielding doesnt prevent other uses of it … There just has be enough to maintain the shielding… Also – solid waste works as well – as well as food supplies..
Its 2 years total travel time … The food supply would be needed either way – either in the return leg or on the ground on mars… In the Mars Direct version of the program, the crew arrives in the Habitat module, for an 18 month stay.
I think they would be staying permanently. Although if they weren’t, the amount of food, water, etc would be further increased to cover a return trip. Ideally, part of what they do on Mars is find ways to produce their own food and fuel, but fuel for the colony not for a return trip. So it wouldn’t have to be freeze-dried etc.
Enough water just to supply a possible 2-year journey would be something like 5,000 gallons I would think. Perhaps 10,000 or more. And remember, it’s not all recycled. I’m talking about just how much would be needed to make the trip, with NONE LEFT at the end, after 2 years of 90% recycling. (The ISS requires at least 500 gallons per year, for 3 to 6 people.) Most likely waste would be used for hydroponics etc, which also requires more water… So the issue of radiation if they end up making the 2-year ’round trip, could be very serious.
If you mean a trip to Mars to put people in a pre-positioned habitat thing, for 18 months, and then somehow bring them back, I think that would be far more expensive and difficult. And there would be plenty of volunteers even for a one-way trip. But I do think it would be important for those accepted to not have anyone left behind who might try to cause trouble “on their behalf.”
It seems ‘unAmerican’ to send astronauts out on a one way trip.
I think the Mars Direct program is the best plan for success.
6 months out to mars, 18 month stay for exploration, 6 month return trip…
As resources get built up on mars larger crews will be possible… Maybe 4 or 6 to start going to 10 or 12 on future flights…
The long-term goal seems to be a permanent colony on Mars, so why not start that right from the get-go?
And we wouldn’t be talking government-employee “astronauts.” At least we don’t HAVE TO BE. And Elon Musk probably isn’t either. Even if NASA is.
If the government wants to pay Musk that much more, I expect he’d happily accept it, and continue to work on his own plans too, which I suspect don’t include return trips. At least not at first. And I wouldn’t be surprised if Musk gets there first, since his method might cost half or less. The people of Musk City on Mars – or maybe Elonville – might be waving to the NASA folks when they finally arrive.
Quite. Wilbur and Orville didn’t have to take their air with them. Or their water. Or enough food for three years. Or shield themselves from solar and cosmic radiation. Or compensate for a microgravity environment. Etc.
This has been quite a good discussion to follow. Thanks.
Even in 1950 (from Destination Moon)
“Have you seen the morning papers? Look at this–“
“Well, you can’t beat pubic opinion. I’ve tried”.
“Public opinion my eye! This is plain propaganda, organized with money and brains. Somebody’s out to get us”.
BTW, a little “the more things change, the more they remain the same”–note that the headlined photo reads “Trouble At the Border!”
I don’t get why anyone would think I don’t think we’re going to space/the stars, EVER. But I think they seriously underestimate the difficulties and costs, especially at the start. It’s quite possible, whether Elon Musk does it or NASA does it, that the first mission to Mars – or the second, or the third – will have everyone die, either before or after they reach Mars. Remember, it happened with the shuttles, too. Twice. And Apollo 1. And almost Apollo 13.
The difficulties are different. I have no idea what you mean by “entirely different level”. The difficulties of space flight in 2021 are more difficult than paddling across the pacific in their complexity, yet we can do it.
Every argument I have made is that we will be able to do it. You have been arguing against that point, and now are changing what you are saying.
Just had to highlight this.
Heartily agree.
In that case I’d prefer not to be the relative of someone who is applying to go on the mission.
The ISS currently recycles about 40% of it’s oxygen and water. We can make fuel, oxygen and water on mars with simple and well understood chemical reactions (the Perseverance Rover is currently making oxygen on mars in an experiment called MOXIE). So you can in fact ‘live off the land’.
I think going to Mars will be difficult and expensive – but if Elon Musk can do it – it can’t be that expensive. As the development of the Falcon 9 and Crew Dragon has demonstrated SpaceX is capable of designing and implementing hardware solutions far quicker and cheaper than NASA with its community of “cost plus” contractors. IF NASA where truly serious about going to Mars they’d finance a series of engineering competitions to help solve any and all outstanding problems, and a COTS style flight testing program to develop a heavy launch capability. 140-150 Tons to LEO would open up Mars missions and a return to the moon. SpaceX could win this competition quite easily – just by putting 4 boosters on a Falcon 9 Heavy – instead of the current 2 boosters…
Oxygen storage a problem? Maybe we have to store it in a solid form – maybe something like calcium peroxide or nitric acid…
Yes, accidents will happen – either by technology failure – or an unexpected event like an impact with dust particles. I dont think that should dissuade the viability and importance of the project. This is why NASA dropped commercial satellites from the Shuttle – flying the shuttle turned out to be far more dangerous than imagined. If there was another accident they wanted to claim the astronauts died for science – not cable tv.
Speaking of incredibly expensive:
A couple of notes:
Are you worried about collisions? In a quicker trip, the crew would be less subject to cosmic radiation.
I think the point there was about the path allowing free-return if there’s a problem, which may not allow for speeding it up.
There are going to be casualties.
Oh for sure. Especially if, as I think is largely inevitable, the Mars missions are one-way trips. Which is why, as I’ve also mentioned before, the Mars volunteers should be selected from people who will not be leaving any relatives behind that might cause trouble: lawsuits, etc.
The astronaut core would take the same radioactive dose from the ISS program as they would take if they’d gone to Mars. I think there are 3 – 5 astronauts have taken a dose as large as if they’d gone to Mars already.
The real issue is that quicker trips dont have a free return trajectory – some are above escape velocity. So if they dont enter Mars orbit – for whatever reason (computer failure, fuel leak, engine failure, etc etc) there is no coming back at all – ever. That is a far greater – and more immediate risk to the crew than an elevated cancer risk.
Doesn’t any non-constant-boost mission have to reach escape velocity?
Earth-orbit escape velocity vs solar escape velocity etc, are different.
And if the ship is going “too fast” for Mars gravity to sling it around back to Earth, you lose the automatic safe return.