I think I would prefer the upper atmosphere of Venus if I had to choose between the two for a one-way trip:
"At an altitude of 50 km above Venusian surface, the environment is the most Earth-like in the solar system – a pressure of approximately 1 bar and temperatures in the 0°C–50°C range. Because there is not a significant pressure difference between the inside and the outside of the breathable-air balloon, any rips or tears would cause gases to diffuse at normal atmospheric mixing rates, giving time to repair any such damages. In addition, humans would not require pressurized suits when outside, merely air to breathe, a protection from the acidic rain; and on some occasions low level protection against heat."
That is the most interesting bit of space knowledge I've ever read. It certainly seems like the potential in Venus is much greater than on Mars. I wonder why the space industry is so fixated on Mars?
Keeping the habitat 50 Km from the surface for decades isn't a trivial task.
Mars also has easily accessible water and a lower gravity. All you can get from Venusian high atmosphere are the gases you capture. On Mars you can mow rocks to get stuff like, say, steel.
Indeed, there's not a lot to recommend a Venusian floating habitat over a pure space station, for example.
However, if you look at what's possible with Mars, things get interesting quickly. Firstly, the CO2 atmosphere and local sub-surface water ice can be used to generate rocket fuel with a very low level of infrastructure, making initial exploration dramatically more efficient. Secondly, Mars has plenty of Sun and near-Earth day/night cycle, making it straightforward to grow food there. The day/night cycle also makes relying on solar power much more feasible, and makes direct communication with Earth more reasonable (since a location on Mars and on Earth will generally have line-of-sight to each other on the order of once per day). Thirdly, local martian materials can be used to maintain a self-sufficient industrialized civilization over an indefinite period of time (local metal ores, water ice, CO2, even Uranium ores, ability to grow food, etc.)
Doing some fact checking, you could build automated processing stations on Venus that could process atmospheric CO2 and water vapor (the former is most of Venusian atmosphere and the latter about 20 ppm) into methane and O2. There is plenty of sunlight as a power source too and an abundant source of heat. The gravity well is much worse than the one you find on Mars, but, as far as an automated facility goes, it's conceivable just to leave it there for decades, let it fill itself to its full capacity over decades and just ship a couple tanks coupled to engines to low orbit (or a cycler one) where a passing spacecraft could pick them up. The empty vehicle could then return to Venus and start its cycle again.
Mars is easier, but there is a lot of Carbon on Venus and it would be nice to be able to ship it elsewhere. Maybe then we could somewhat reduce the greenhouse effect and make it more comfortable over a couple hundred thousand years.
I've wondered about that too. While it would be hard to float any kind of space colony there even with giant dirigibles, I've always felt that Venus' thick, gaseous atmosphere offers tremendous long-term potential, and I don't understand why we don't fire more probes at it. There are extremophile bacteria on earth that live in hot or chemically hostile conditions, many of which are anaerobic. It seems like we could try some long-term terraforming efforts at little short-term cost.
It's not really "new" since it was conceptualized in 1977 but recent technological advances have made it a real prototype (2005) and it will be tested on the space-station in 2013.
The guy who designed it, Franklin Chang-Diaz, is incredible as well as his lifestory - literally made his farfetched startrek-inspired dream to become an astronaut come true by sheer willpower and he went to MIT.
Days is ridiculous. A few months instead of the years chemical rockets would take is probably a better estimate. The big advantage to VASMIR is that, unlike the Deep Space 1-style ion engine you can get reasonable thrust and a high specific impulse at the same time.
[SpaceX] has won $75 million from the US space agency NASA to help its pursuit of developing a spacecraft...
I was wondering what possible economic rationale a "private" mission to Mars could have, given that there are a limited number of billionaire space tourists whose ultimate dream is to be locked in a space the size of a bus for six years.
Now I know. They're in the traditional, lucrative business of collecting government grants.
What I'm seeing here is a contractor. Big deal. Exactly what is the difference here between SpaceX and, say, Grumman Aircraft Engineering in 1962?
Grumman wasn't part of the government. It was a corporation.
The point of "private" space ventures is that they're supposed to have a different business model, not just a different approach to branding themselves. Thus far their big business-model innovation is to collect checks from NASA without ever using the words contractor or NASA.
Since I'm not a US tax payer I should be careful. Its true, SpaceX would not be where they are today without massive government support.
But consider the following.
First, they are a lot more cost efficient. The Falcon Heavy is supposed to be 6 times cheaper per ton to LEO than the Delta IV Heavy. This can save the US government as well as many companies around the world lots of money.
Second, the ability to jump in, just when the, expensive, shuttle program runs out seems to be very helpful for the USA as a - if not the - space nation. Without SpaceX the US would depend on Russia to send astronauts to the ISS and anywhere else in space for many, many years.
Also, I would be careful about dissing "space tourists". Many of the so called tourists have actually done scientific experiments in space. I believe most of them did not fly, so they can show the "I was there" pics at home. No, they wanted to be astronauts since they were little boys, more than anything else in the world! This is pure speculation, but if NASA would auction their astronaut positions to people who match the minimum requirements, they might be profitable tomorrow.
Same goes for Elon Musk and Mars. I've read many times, he is a betrayer and just wants make money at the SpaceX IPO. I know you didn't state this and maybe its actually true. But I don't believe it. I think he and others really want to have humans on Mars and if possible they want to fly by them self. I find it totally plausible that the first manned mission to Mars will be financed by the crew and their private supporters. Just consider how much people pay to be the XXXth person to be on Mount Everest. And thats arguable not less dangerous, let alone the hardship in the death zone.
How much would be the final prize on a auction that determines who will likely be the first human in history on a different planet?
Last but not least, whats wrong about Grunman and the Lunar Module? From the wikipedia article you cited:
"Though initially unpopular and plagued with several delays in its development, the LM eventually became the most reliable component of the Apollo/Saturn system, the only one never to suffer any failure that significantly impacted a mission,[1] and in at least one instance (LM-7 Aquarius) greatly exceeded its design requirements."
But keep in mind that SpaceX's lineup of launch vehicles will probably allow them to capture a rather substantial segment of worldwide launch contracts.
This is not a small market.
We're talking about many billions of dollars. And their vehicles are both more capable and dramatically cheaper than the competition. It seems highly likely that they will be rolling in billions of dollars of profit in a rather short period of time.
Take billions of dollars of excess revenue per year, roll it into more R&D. Take additional billions and an engineering base from a newly formed space tourism industry and add that. And then maybe it doesn't look so crazy if SpaceX is sending humans to Mars on their own dime, independent of any government funding.
This is a great headline-grabber but I still see landing a man on Mars as being an awful long way off.
I heard Jerry Pournelle talking about this and he said something like landing a man on the Moon and establishing a lunar colony is an engineering problem. Landing a man on Mars is a science problem.
The difference? We can already do the former. it's simply a question of money and the will to do it. The problems are basically solved.
Landing a man on Mars has far bigger problems. The round trip (or even one way) journey with current propulsion technology will take an incredibly long time (upwards of 2 years). How do you keep someone alive that long? What about the psychology of isolation? Sustained radiation exposure is a real problem.
Personally I see manned spaceflight, particularly to other planets, as being largely a propaganda exercise until:
1. The cost of lifting into orbit (per kg) goes down. Way down. Like 2 or even 3 orders of magnitude; and
2. We have a much faster means of propulsion to make journey lengths manageable.
(1) is probably the easiest to solve. SpaceX's launch prices are actually quite low (but those are fairly low orbits; launching to another planet is more expensive). Virgin Galactic and other private suborbital efforts will (hopefully) lead to a dramatic cost reduction of getting into orbit.
(2) is a fundamentally hard problem. Ideas such as solar sails and the like are far from being practical (plus with a solar sail, how do you get back?). Magnetic fields as solar sails is an interesting idea but has a whole bunch of other problems.
Otherwise you need to eject mass to give you velocity. That mass is something you have to carry. The more mass (fuel) you carry, the less effective each gram is (in delta-V terms).
What I think will probably drive this is the coming earthbound resource shortages (inevitable unless we drastically reduce population; it's simply a question of when) that will drive a permanent presence in space. Once you have a huge industrial manufacturing capacity in space, the economics completely change.
EDIT: I agree with other comments in that a one-way (colonization) mission makes far more sense but I'm still unconvinced this will happen anytime soon, probably not in my lifetime.
Mars does have some interesting properties though if a colony can become self-sustaining:
1. Lower gravity. This actually makes the idea of a space elevator far more feasible [1]; and
2. Mars has features that extend beyond the atmosphere. The atmosphere is ~11km thick. Olympus Mons is 25km high.
I've read seemingly informed speculation that if we (the human race) had evolved on Mars, we'd already be heavily spacebound since it would be far, far easier.
This is what might justify colonizing Mars. Not that that is an easy problem.
At this point, sending humans to Mars is also just an engineering problem, not a science problem.
The trip time using conventional chemical rockets is limited to modified Hohmann transfer orbits of around six to eight months each way, and the duration on the surface would be about eighteen months before the next orbital launch window between Earth and Mars. With basic well-understood radiation mitigation techniques, total radiation exposure for each astronaut over the duration of the mission is around 50 rem, less than the amount needed to increase by 1% the chances of a 35-year old adult of developing cancer at some point later in life, a lower risk than by spending the same amount of time smoking cigarettes on Earth.
Getting the astronauts back isn't prohibitively more difficult than getting them there in the first place: the energy expenditure for escaping the surface is 17% of the Earth's, and using the Mars Direct mission architecture, you can send a return vehicle ahead of time with seed hydrogen to manufacture liquid methane propellant and liquid oxygen oxidizer from the carbon dioxide air, through the Sabatier reaction for both and also with electrical dissociation of the carbon dioxide for more oxygen. You can also test it in flight after producing its fuel before deciding to launch the humans to Mars in the first place.
We still need a heavier-lift heavy lift vehicle of at least 100 to 140 tonnes to LEO to start being able to send major assets to the Mars surface in one shot, but SpaceX is becoming increasingly credible as a possible creator of such a vehicle. Putting humans on Mars within twenty years would require at least a few billion dollars a year (a small fraction of NASA's budget) and ironing out some engineering details, but is entirely doable. The biggest obstacle is just having leadership with a sustained focus on that goal over the course of the couple of decades required, and that hasn't been forthcoming from within government, but perhaps could be supplied from a private entity. SpaceX has been laying down a solid record of presenting visionary plans for spacefaring capabilities and then making them happen.
I second the first two paragraphs but I'm not sure about the third one.
I want to see a 140t to LEO rocket, too and I'm sure SpaceX is already building it.* However, is this really necessary? I think the orignal, soviet moon flight plan would have been to put several stages into LEO and combine them there. The plan was given up, but I think it should still be possible if no larger rocket is available soon. Consider, SpaceX plans to lunch 10 Flacon heavy (53t to LEO) per year at a combined cost of 800-1250 million.*
And of course, the Saturn V did already put 119t to LEO in 1967.
Hence, their knowledge in building space stations like MIR.
How much was bailing out those rust belt dinosaurs again?
Besides the added complexity of assembling components together in LEO, placing any mass into low Earth orbit is really inconsistent with putting it into a trans Mars trajectory and adds a giant extra delta-V penalty. It's a much different orbital inclination, plus there's the added energy loss of circularizing a trajectory into low-Earth orbit and later boosting out into a hyperbolic escape trajectory. As far as I understand it, it would be faster and cheaper to develop a true heavy lift launcher.
Why do you say the inclination is different? You can go into LEO at any inclination.
I also don't see why you need more delta-v to go from launch orbit to circular orbit to transfer orbit compared to the transfer orbit directly. My orbital mechanics are rusty, but it seems to me that since you need to lift the perigee from Earth's surface to Mars orbit, you'll pass the circular orbit on the way.
If you go into low Earth orbit from the Earth's surface, you need to go into an orbital inclination equal to the latitude of your launch site - which is extremely unhelpful if you want to then take that mass anywhere else in the solar system. You also need to circularize your orbit, then later boost that mass from circular orbit to hyperbolic escape orbit - also extremely wasteful.
I still don't see why circularizing the orbit would be wasteful. Circularizing an elliptical orbit at apogee still requires positive delta-v, which will help you on the way to the hyperbolic orbit. Only if you want to circularize at perigee would you need to slow down, which would indeed be extremely wasteful. It's true that you get more energy boost for the delta-v if you do it early rather than late, but I don't know if the ellipticity of the launch orbit is high enough for that difference to qualify as "extremely" wasteful. But maybe it is.
True, a better Saturn V would be the best. I was just trying to think about, if for whatever reasons, a better rocket would not get ready in time. But maybe what I wrote was just plain bullshit. ;-)
Of course it would make more sense to send all the small rockets towards mars at the same time and 'somehow' combine them but that doesn't sound easy either.
If you boost something up to orbital velocity and LEO altitude but don't circularize, its orbit still intersects the atmosphere, if not the earth. The delta-v required to keep from falling back down would be better used to push into whatever transfer orbit you want.
To some extend thats of course possible. Wouldn't that be funny if in the end, all crew member travel separately because its cheaper? :-D Now thats isolation! At least they would have short latency when talking to each other.
Of course, once you've build a big enough rocket, its usually cheaper than multiple small ones. But there is a market for medium size rockets like the Falcon Heavy already. Not so, for bigger rockets - yet.
I'm not sure we need to dramatically reduce the population in order for the Earth to sustain us, we just can't let it continue to grow unchecked forever.
But that's in terms of total agricultural output, under a scenario where you stop feeding a large portion of your crops to livestock, and where large amounts of food aren't wasted. The first line in the wiki article you link to mentions that roughly 1/6 of the planet is malnourished. The WFP says that ~6 million children die of malnutrition and hunger related diseases annually in developing countries. Meanwhile, the US feeds something like 90% of its soy, 80% of its corn and 70% of its other grain to livestock, much of which we kill for meat. This fact -- that the rich choose to consume luxury products with relatively large footprints in terms of limited resources, such as meat when the world's poorest are malnourished, or beer or consumer electronics when many have insufficient access to clean water -- makes me think that our future ability to sufficiently feed 9-10 billion people will be less a function our total agricultural resources, and more a function of the disparity between the rich and the poor.
As attractive as your logic sounds, it is wrong. If the rich world consumed fewer food resources, that would not mean the poor would eat more. There is not some fixed quantity of food that is distributed by some central zero-sum mechanism. Rather, malnourished people are malnourished because they live in areas with dysfunctional economies and governments. Producing food isn't the problem, distribution is.
I totally agree that the issue isn't producing food but rather distributing it process. I further agree that this isn't a strictly zero-sum mechanism.
But yeah, if rich people consumed fewer food resources, prices would drop, and some malnourished people who can't afford sufficient food now would be able to afford more. Blaming the problem on dysfunctional local economies and governments is facile way of absolving oneself of personal responsibility -- "My consumption of limited resources isn't the problem; it's corrupt governments. I can keep consuming however I like, comfortable in the knowledge that I'm not causing harm to anyone else". Yes, dysfunctional governments and economies in developing countries are part of the problem, and no matter what rich people do or do not consume, they probably won't help the hungry people in N. Korea by doing so. But there are plenty of places where that's not the case. The fact that the 2007-2008 food crisis did meaningfully impact a lot of people in developing countries should indicate that we are all connected to the same global food economy, and what we do with our agricultural resources in rich countries can and does impact the prices and availability in developing ones.
Energy is a bigger problem. While we can make energy from renewable sources it is far more expensive (which has ramifications for our entire way of life) and not yet established that we could provide it on the scale necessary to replace our non-renewable sources.
But the biggest problem is resources. Metals, rare earth elements and the like. These are largely irreplaceable in the sense that we can produce so much of them by (typically) digging fairly shallow holes in the ground. We're already going to some fairly inhospitable places to meet our insatiable demand (eg the Arctic in northern Canada and Europe, the Andes).
If we're not careful we may well find our own answer to the Fermi paradox.
Actually, food is the only problem when it comes to whether or not a population is sustainable. Enery and resource usage determine if a particular lifestyle is sustainable for a given population. Given sufficient energy other resource problems tend to go away (e.g. the amount of various minerals that are in solution within the oceans is mind-boggling but it takes energy to get them out). In the end the lifestyle any particular population can sustain will come down to an energy production/capture and management problem.
> Energy and resource usage determine if a particular lifestyle is sustainable for a given population
And maintaining a particular lifestyle tends to be a strong catalyst for war as a means of solving population problems. The problem is we're now at a point where such a thing could be truly devastating.
While the threat of mutually-assured destruction has kept the specter of nuclear war at bay, I believe you'll see the means of destruction migrate to more fine-grained methods, most notably genetic engineering and nanotechnology, both of which will become increasingly accessible on a scale nuclear technology never has.
> Given sufficient energy other resource problems tend to go away
I agree but all the energy replacements in the foreseeable future will make energy more expensive not cheaper.
Fission-based energy has the same fuel problem fossil fuelds do (the unfulfilled promises of thorium reactors notwithstanding).
Fusion-based energy has huge problems, some of which are fairly fundamental and not likely to be solved anytime soon.
The most obvious problem (containment of plasma) is probably solvable with magnetism.
The bigger problem is neutrons. You currently can't leave a fusion reactor on for very long before it starts destroying its container.
He-3 (Helium-3) is one possibly solution to this but that stuff is incredibly rare and may well present the same fuel problems as any other energy source.
Interestingly there's a supply of it on the Moon due to billions of years of solar wind on an atmosphere-less body.
> In the end the lifestyle any particular population can sustain will come down to an energy production/capture and management problem.
With some fairly nasty corrections that may have undesirable consequences for the rest of us.
Anyway, that's why I say food is the least of our problems. We can already produce enough food for the present population. It's unclear how much longer we can support the lifestyle of that same population.
Energy factors in here too as we're now fairly distant from our food (given how urbanized the developed world generally is) but population redistribution will occur naturally as the energy equation changes.
Actually, food is the only problem when it comes to whether or not a population is sustainable. Enery and resource usage determine if a particular lifestyle is sustainable for a given population.
Food needs aren't static: They vary considerably from person to person and can be changed for a particular individual who sets out to change their lifestyle. Also, a lot of the energy that is currently being expended for transportation could be readily replaced by human energy if walking and biking became more popular -- which is both an energy issue and a lifestyle issue.
I currently live without a car and I have a medical condition that typically causes one to have a very high calorie need. I've worked hard on getting myself healthier and my calorie need has shrunk dramatically. In some ways it is counterintuitive, but living without a car has turned out to be an asset in that regard. Doing a lot of walking is one of the things that has helped me get healthier and shrink my calorie needs. Obesity is epidemic in the US and we do not have a very pedestrian-friendly environment. Most Americans seem unable to imagine living without a car.
So this assumption that energy and some kind of non-food fuel are separate from food and people just doesn't quite compute for me. They aren't totally separate issues. If people walked more and drove less, it would leave more gasoline and other fuel sources for other things and, at least in America, likely substantially lower food needs as well.
I'm not a rocket scientist and you seem to be very knowledgeable. However, I feel like you are overstating the problems and should drink some of that "homo faber can do anything he/she wants" cool aid. ;-)
I mean, "psychology of isolation" come on! People have been in super tiny submarines for months, while water bombs are exploding around them all night long. And thats at least two generations ago.
I doubt that von Braun and co. had solved all the problems for flying to the moon, when Kennedy set the goal. I have no doubts that they would have put a man on Mars soon after, had the program continued. When the Saturn V was retired, humanity was put four decades back - and counting. Its only a question of will. Do we want to have nicer cars or advance the frontier of humanity?
Currently the method that's worked best is to bounce down a sturdy probe on giant balloons, and now NASA is trying a quite rube-goldberg lander that hangs below its retrorockets. Still very much in the experimenting phase.
It's true that using aerobraking alone for an incoming vessel from Earth landing on Mars would be infeasible. Landing with thrust, like we did on the Moon forty years ago, but also using assistance from aerobraking and parachutes, is not an issue.
Phoenix successfully landed and if the Mars Science Laboratory manages to land safely we might get ready to conclude that at least NASA has landing on Mars figured out.
It’s not really experimenting, NASA simply has progressively scaled up their landers. It’s hard but they know how to do it.
This is actually really simple and not a problem at all -- you just have to understand orbital mechanics a bit. Basically, you angle the solar sail so that its force is directed against your direction of travel along your orbit. This slows you down, causing you to start spiraling in toward the sun. Then you change angle so that you start speeding up again and match orbital velocities just as you arrive at your destination.
But it's a separate issue anyway -- solar sail technology (or Vasimir, or Nuclear Thermal) is no more required for exploring Mars than jet airplane technology was required for exploring North America.
"We'll probably put a first man in space in about three years," Elon Musk told the Wall Street Journal Saturday. "We're going all the way to Mars, I think... best case 10 years, worst case 15 to 20 years."
It's pretty obvious from the context though. SpaceX's vehicles are capable of putting robots on Mars right now and will probably due so as part of some future NASA, ESA, etc. contract within the next 5 years, easily.
Do you think so? A Martian lander is an easier job than an Earth lander, and they've already built one of those. In fact, there was the story here the other about how a Dragon can theoretically land on Mars, so if they just manage to build a big enough booster it should be well within their capabilities.
Still very expensive, of course... they'd need to talk someone into paying for it.
Why would a Martian lander be easier? On earth you get to use parachutes. The Martian atmosphere is too thin to use parachutes for any significant payload.
I know SpaceX is planning on a thrust-based landign system for Dragon, but the "lander" they've "already built" relies on parachutes.
Targeting 10-20 years is basically wishful thinking. The time horizon is too long to make serious estimates. Look at fusion! Workable fusion has been 10-20 years off as long as I can remember.
It took 7 years to go from a primitive orbital capsule to a manned lunar landing.
With 1960s technology.
Don't use the pace of NASA progress within the last 2 decades as some sort of benchmark, it has no meaning and no correlation to anything other than government handouts to important congressional districts.
What is possible and what will be possible within 10-20 years is a great deal more than what has been done.
SpaceX is seemingly capable of building a Saturn V class launch vehicle in less time and for far less money than was done historically. Given that I don't doubt that they'll be able to do amazing things.
I'm not looking at NASA's progress at all here. I'm sure SpaceX can accomplish a lot in that time frame, but saying they'll definitely be on Mars then is simply wishful thinking. Lift capacity is not the sole limiting factor.
Certainly. But look at the simple facts. From 1961 through the 1990s only 2 organizations (the US and Soviet governments) had developed or flown manned spacecraft. Since then 6 organizations have developed, built, and flown such spacecraft: China, Scaled Composites (a sub-orbital flight), SpaceX (an unmanned test flight of a crew capsule), ESA and Japan (ISS modules and re-supply craft), and Bigelow Aerospace (unmanned tests of inflatable space habitats). It's especially notable that half of these achievements are from non-governmental activities.
The point being: the ability to build manned spacecraft is much less difficult and much less rare than it once was, and no longer restricted to governments. Given that, it's no small stretch to imagine impressive increases in lift capacity coupled with equally impressive reductions in launch cost facilitating even greater fluency with manned spacecraft design, construction, and operation.
It is not so terribly difficult to mount a manned mission to Mars as some people seem to imagine. Read Zubrin's "The Case For Mars" to see how it can be done rather efficiently. Given the projected payload capacity of the proposed Falcon XX launcher it would really only take a few launches to get things running.
Given that SpaceX has already built a seemingly functional crew capsule will it really take much more than 20 more years to build and test all of the necessary pre-requisite components of a manned Mars mission? I don't think the timeline is so terribly optimistic really.
In order to send a man to Mars and bring him back alive, you'll need:
- a propulsion system that can send an habitat and supplies good for, at least, 6 months.
- a separate trip to send the supplies for the return mission and park it in Martian orbit for rendezvous when the manned vehicle arrives
If you also want the crew to land on Mars, you'll need a lander. You may consider doing the surface-to-orbit return mission on a separate vehicle you can land before. You may consider sending supplies and a shielded habitat (Martian surface is about as shielded from cosmic radiation as space itself - not at all) if you want the humans to stay.
20 years is a very hard schedule for that.
You can send the unmanned parts with current technologies, but the manned part depends heavily on the development of adequate shielding and/or adequate NTRs to make effective use of the reaction mass the spacecraft carries.
If shielding is developed before, you could even make the whole thing easier - you put a shielded habitat in an Aldrin cycler orbit and just send crew and supplies (and spares for the habitat) to rendezvous with it when it passes by Earth leave the habitat when it's time to enter Martian orbit. The trip is longer, but it's easier if you don't have to give the whole habitat the required delta-V.
The propulsion system from Earth to Mars could just be a scaled-up version of the systems we've been using to send probes to Mars for decades.
Yes, it would be wisest to send at least two trips, so that equipment can be ready for the crew when they arrive. (Especially if you're making return-trip fuel from local resources.)
Radiation is a problem for a manned mission to Mars, but I understand the numbers work out to less lifetime risk of cancer than smoking. (So send former smokers without any cigs and you've improved their expected lifespan.)
> The propulsion system from Earth to Mars could just be a scaled-up version of the systems we've been using to send probes to Mars for decades.
You would have to send a Mir-sized object (in order to accommodate humans on their way up) on a transfer orbit to Mars, with the required shielding and supplies to keep the crew alive for at least 6 months, plus fuel for braking when they need to inject themselves into Martian orbit (or, at least, to circularize the orbit after atmospheric braking). Doing this with chemical rockets is possible, but operational NTRs would decrease the time for the trip and expose the crew to less radiation.
I am not sure the numbers for radiological risk are that low. Besides, the longer they stay en-route, the higher the risk from a CME catching them. If they are on Mars, at least they have a planet to shield them 50% of the time.
I think so. I was talking to a friend at ESA the other day and he seemed to be pretty positive about getting to Mars soon.
Of course, getting /back/ from Mars is an entirely different proposition altogether. It's pretty likely the first man on Mars will be taking a one-way trip (and there are definitely people willing to do this).
Yeah, I read something about that being the opinion of Buzz Aldrin. But a on way trip seems like a hard sell. Doesn't the government have to approve something like that? Immigration, maybe? And it just doesn't some like a good PR move to approve that.
Thanks for that link. After reading it, I agree: a one-way mission would not be a "suicide mission" but more like a high-risk adventure. History has proven that many people relish these opportunities.
And it's not even that there might never be a chance for return; just that it's not part of any of the current planning. Would be attractive to the same sorts of people who in the 14th and 15th centuries sailed in wooden ships to the "new world"
I submitted a link to an article about it here, http://news.ycombinator.com/item?id=2478079 . I also linked to a couple of books, including one containing the linked article, To Boldly Go: A One-Way Human Mission to Mars, in a comment.
Getting a man to Mars if you don't need him to get home again is probably within capabilities. Getting a man to Mars if you don't mind him being dead when he lands is even easier!
Last year the journal of cosmology had an issue devoted to problems related to Mars. There are many people who believe putting people on Mars is completely feasible. The most well known is maybe Robert Zubrin, advisor to NASA, who has a fairly well thought out plan ("Mars Direct") how to establish an outpost on Mars by a series of trips that are all within our current technological abilities, i.e. they don't require experimental propulsion systems. He has also written a very good book on the topic.
"I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to Earth."
Doesn't sound like they have a whole load of confidence.
Elon Musk is not Kennedy. His default style of speech is less political and usually not aimed at inspiration.
You can draw no inferences about his confidence from this comparison.
What you could take from this comparison, if you were so inclined, is that when it comes to inspiring Americans about space travel, Musk&Co. are less motivational than what worked in the past. Time will tell if you need the same motivational leader to accomplish something like this in the private sector.
Kennedy was also assassinated. There is likely a direct link between how inspirational he was and the fact that he was assassinated: Jesus was crucified, Joan of Arc was burned at the stake, and Dr. Martin Luther King was shot. If Elon Musk wants to get the task done without ending up dead for it, speaking in a less inspirational style may be the better path.
Edit: It's a completely serious observation, not intended as funny at all. Anyone care to explain the downvote? Or argue the point?
Thinking about all this, maybe kids will no longer want to be astronauts when they grow up, but entrepreneurs who get to send people to the frontiers of space.
It's so fascinating to see a private enterprise undertake these inspirational endeavours.
Put men on mars or launch hundreds of robots and satellites to survey the solar system? Which will produce more knowledge? Which will be more cost effective? In 100 years, which path will lead to more increased human space travel?
Sending robots is agile space exploration. Release early, release often. We can lose a few robots and use more experimental technology quicker. Sending humans sounds cool but we shouldn't go until it's as safe as commercial aviation then we can do it frequently.
> Sending humans sounds cool but we shouldn't go until it's as safe as commercial aviation then we can do it frequently.
That's almost asking for it never to happen at all. Air travel has a safety rate of 1 fatality per 2 billion passenger miles, making it one of the safest modes of transport out there. When Europeans first started exploring the Americas, the fatality rates were much higher, and people simply went in knowing that what they were doing was risky, but also fundamentally really cool.
Fatalities per distance isn't a very good metric for safety. Otherwise, you could send 3000 humans 1 light year away and as long as 1 passenger survives, it's safer than air travel per billion passenger miles. Fatalities per trip makes for a better comparison as the vast majority of the risk for space travel, like with air travel, is on takeoff and landing.
Which one would inspire more people to pursue a career in aerospace? Which one would result in more legends? Do we care about the small robot that burned in Martian atmosphere because someone used kilometers instead of miles?
We need robots to pave the way, but we also need manned expeditions to bring back stories.
Which one would inspire more people to pursue a career in aerospace?
And just many aerospace companies do you know of that are desperate to hire people because there isn't enough talent?
The aerospace industry has many challenges, but last I heard an undersupply of people who would love to build planes and space probes was not one of them. It's a demand problem, not a supply problem.
How many famous astronauts can you name? The first couple of people will get some fame. We will generate a lot more high-tech careers with the other path in both aerospace and robotics, which will also apply on earth.
You don't think the Mars rovers inspired a few people to become engineers? The path that I am describing will create more astronauts in 100 years because the technology will advance quicker. We can experiment with new technologies and ideas.
Your cell phone has more computing power than the Space Shuttle. Human space flight advances too slowly.
We need to apply Moore's Law then insert humans after we're farther along the curve.
You have a good path, but humans have different flight requirements than probes. If we tailor spaceflight development to robotic probes, the technologies required for human flight may never be developed.
Pathfinder inspired me to be an engineer. Before then, I had no idea what I wanted to do. After that, I went to college to be an engineer and specialized in robotics.
but we shouldn't go until it's as safe as commercial aviation
I would not put the goal that far away. There are people taking a ~5% (nowadays; this used to be much higher in the early years) fatality risk to climb Everest. I expect we would get plenty of capable volunteers for that risk on a Mars mission, and I also think we should pick the best and send them.
I'm in space robotics and albeit I believe that huge advances will be made in this area, we are still not anywhere close to human capabilities. Why else do you think, the Japanese are sending dozens of their people to lethal work at Fukushima?
I do believe though, that remote controlled and partly autonomous robots are already capable of helping humans on a mission like Mars exploration and colonization.
This is not to mention all the very successful robot programs like Voyager I/II, Spirit/Opportunity etc. But those are smal scale projects in my mind. They are cost efficient, but I doubt you could do what you could do with humans, just because you put the same amount of money behind it now. Of course, there could be breakthroughs in AI tomorrow that change that game. But putting a human on the moon is doable for decades now and its about time that someone has the balls to do it.
disclaimer: Elon Musk is my hero and I'm a hopeless fan boy.
I think everyone understands that robots aren't as capable has humans.
The idea is to improve their usefulness. For example, the ability to mine planets and asteroids. The plan is to send people to Mars and do what tasks that a robot can't? Having people do mining on Mars, for example, will be very costly and dangerous.
Of course machines aka robots have to do the mining. But I believe you need humans in place to plan and control effectively.
I think the real dispute is about the goals of space exploration. A lot of scientist only want to collect data. That is very important but space exploration is about something else, too. Its about expanding the human territory. You don't have to like the idea. But me and many others do and even think it is a necessary long term.
Sorry to belabor this but if we go agile, things could change quite rapidly.
Consider that within 10 years, we might be sending 52 private flights a year, containing robotic explorers, to various destinations in the solar system. One of them discovers valuable resources (e.g. gold, "precious metals", 1000 caret diamonds, etc). Now private industry has a reason to build a business in space. They need to get the resources back to earth. Private funding goes up exponentially for robotics, factories in space, and probably human space travel. VC money might even move from social to outer space. :-)
I think we all agree we eventually want humans in space.
However, as I previously wrote, I believe there will be a lot more people traveling, perhaps living, on Mars in 100 years, if we use the "agile" method now.
We went to the moon over 40 years ago. It only took two accidents to really slow the process down. Now the US' plan for human space flight is to pay someone else.
You might be right about your "agile method" but I would bet on the other horse. How realistic is it, to take mined material back to earth for a profit? I can't think of any material even if prices for transport would see a landslide.
Also, I don't agree that Apollo was killed because of Mission # 1/13, if thats what you mean. Apollo was most of all stopped because it had done its purpose, showing the world that the US was superior to the UDSSR. Why exactly the few remaining missions, where killed puzzles me though.
There's nothing valuable enough to profitably mine from asteroids. Even if we discovered an asteroid of pure gold it would not be worth the energy required to bring it back to earth.
You can stockpile supplies before humans get there. It doesn't have to self-sustain for as long as the supplies last. You can also send machinery to extract materials from the environment.
"At an altitude of 50 km above Venusian surface, the environment is the most Earth-like in the solar system – a pressure of approximately 1 bar and temperatures in the 0°C–50°C range. Because there is not a significant pressure difference between the inside and the outside of the breathable-air balloon, any rips or tears would cause gases to diffuse at normal atmospheric mixing rates, giving time to repair any such damages. In addition, humans would not require pressurized suits when outside, merely air to breathe, a protection from the acidic rain; and on some occasions low level protection against heat."
http://en.wikipedia.org/wiki/Colonization_of_Venus#Aerostat_...
Just don't fall off the edge... :)