Spacecraft aimed at taking humanity beyond the Moon and across the vast reaches of the solar system are beset by physical and chemical limits. Credit: NASA
Human expansion across the Solar System is an optimist’s fantasy. Why? Because of the clash of two titans: physics versus chemistry.
In the red corner, the laws of physics argue that an enormous amount of energy is required to send a human payload out of Earth’s gravitational field to its deep space destination and back again.
In the blue corner, the laws of chemistry argue that there is a hard limit to how much energy you can extract from the rocket fuel, and that no amount of ingenuity will change that.
Start with a lightweight payload – a dozen astronauts collectively weighing less than a tonne. Now add the life support systems for a one-year journey, with sufficient food, water, oxygen and an energy source to keep their living quarters warm and bright. Fifty tonnes, perhaps?
Add the rockets and rocket fuel for mid-course corrections, and for landing somewhere interesting then taking off to return to Earth, and the mass spirals to excess.
The laws of physics are immutable. According to these laws, accelerating that large mass and fighting against planetary gravitational fields requires a tremendous amount of energy.
Now consider the laws of chemistry. You can’t change them by legislation. The energy content that can be liberated from rocket fuel, and the propulsion force that can be generated, depend on the mass of the fuel, the molecular bond energies and the temperature at which the chemicals burn.
Scientists and rocket engineers have known this for more than a century and have worked hard to optimise all the parameters. But at the end of the day, there is only so much that you can get out of the rocket fuel – and it’s not enough.
Somehow, the fact that this clash of the titans restricts our ability to undertake deep space flights doesn’t feel right. Surely the magic of our success in electronics and information systems should apply?
Moore’s law tells us that every two years the number of transistors in an integrated circuit doubles. Futurologists assure us that the total volume of humanity’s knowledge doubles every five years. Why, then, shouldn’t our ability to lift a payload double every five, 10 or even 20 years?
Sadly, the analogy does not apply. In the case of electronics and information systems, we are dealing with soft rules, related to the limits of human ingenuity. In the case of space flight, we are dealing with hard rules, related to the limits of physics and chemistry.
Rocket engineers and scientists have been battling these limits of physics and chemistry for years, with diminishing prospects for further gains.
Add to these hard limits the fear of failure from nervous governments worried about the political backlash if something goes wrong and, no surprise, the added weight for redundant safety and life-support systems makes return trips to other planets utterly impractical.
The solution, advocated in Cosmos by astrophysicist Paul Davies (“One-way ticket to Mars”), is to encourage one-way missions.
Davies’ hope is that the colonisers might be able to survive indefinitely by mining oxygen, water, hydrogen and other resources at the destination.
While possible in principle, this would be very difficult in practice because of the low grade of the resources. So the most practical solution is to offer people the opportunity to go on a one-way mission, with a peaceful end administered after many months or years of exploration and discovery.
I’d go. I bet lots of other seemingly normal but deeply inquisitive people would too.
What government would fund such a suicide mission? Probably none. So the much more realistic opportunities for manned space travel 50 years from now are orbital flights for tourism, and suborbital flights for high-speed travel from one side of the planet to the other, such as from Melbourne to London.
Let’s take orbital tourism. Too trivial, perhaps? Not if you consider the hundreds of billions of dollars that are spent every year on adventure for adventure’s sake.
Or take suborbital hops. Demonstrated as impractical by the dearth of supersonic airliners? Not at all.
Air breathing, winged supersonic airliners are impractical because they expend vast amounts of fuel overcoming air friction and create sonic booms that restrict their flight paths.
In contrast, suborbital flights – using the principles pioneered by Burt Rutan and Virgin Galactic – are likely to be quicker and more environmentally friendly: they don’t have to burn fuel in the air trying to push through our thick atmosphere for 20 hours or more; in the vacuum of space, they could traverse the distance between Melbourne and London in just a few hours. And there would be no restriction in the choice of routes and cities.
Wouldn’t it be great to have a taste of the future today? Yes: which is why I booked a flight on Virgin Galactic.
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Hi, and thanks for the article. Why not lift the ship into orbit then re-load it with fuel. At the other end you send a small ship down. You could build a monster in earths orbit. Big enough to supply the mission. And yes. I would go even if its one way. No hesitation.
Cheers
http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion
Get it 99% clean, and then clean up the best we can afterward. Stick with ships in the 8 million ton range. Launch one every 10 years. Goals should be building colonies, asteroid mining, and other big/long term goals. Not gathering small stones and pics.
Lack of long term thinking will prevent it.
Boilerplate. The only thing missing from the cherry-picked assertions is the reminder “but we have to spend the money on the pooooooorrrrr!!!!”
You don’t need chemical rockets for every trip to Mars. Set up cycling spaceships and all you need to do is get out beyond orbital velocity, hook up to a cycler and ride it to your destination.
The “one way” trip is easily rebranded as “colonization.” You’ll have ten times more people on the wait list than vacancies in your first hour.
There’s lots more, but when I read these kinds of things, they all seem to be like the New Atheism: a stalking horse for someone’s political agenda.
“Powered flight? Impossible! Humans are too heavy!”
“Breaking the sound barrier? Are you mad? You’ll be smashed to pieces!”
“Sending astronauts to the Moon? Insanity! No rocket would ever be powerful enough!”
I call complete and total BS on this article.
First it postulates that ONLY chemical rockets as they exist now will forever be the only means of traversing space. Forget ion engines, plasma rockets, nuclear rockets, steam rockets, and solar sails, already proven feasible and being developed by various interests.
Second, even if what it proposes is true (its mostly not), it still completely ignores a very important variable in its space travel equation: habitat technology. If we develop long-enduring, robust habitats that can astronauts healthy and safe for months or even years at a time, even chemical rockets would be enough to move humans into the greater solar system. The voyages may take longer, but if the explorers can remain safe, active, and productive during that time, what would that matter? I’ve long believed that the key to a increased human presence space isn’t ever more powerful rockets, but durable space stations, or spacecraft built like them like NASA’s recently proposed Nautilus-X.
Lastly, the end of the article reads like a free ad for Virgin Galactic. I realize VG is doing a lot of good work and is probably shoveling a good deal of ad dollars at COSMOS, but let’s try and keep our fanboyisms to a minimum, please.
That seems rather silly an argument to make about rocket fuel. This reminds me of old debates of how old the sun could be based on how much coal is in it and how long that much coal could burn.
It seems pretty obvious that rocketing through the stars on chemical fuel is only one step above trying to have a steam powered starship. But once we look at other options with more potent fuel sources the difficulty drops like a stone.
That just leaves us with the safety issues of so much radioactive material being launched into orbit.
Don’t use chemical fuels, go nuke. Or use light sails powered by banks of lasers at home, don’t accelerate the mass of the fuel. There are answers if are willing to change your assumptions.
you forget the architectures proposed by Paul Spudis, to mine and use lunar resources to produce fuel.
a VASIMR powered by a Polywell. Look up the works of the late Prof. Robert W. Bussard. Specifically the Google video titled “Should Google go Nuclear? Clean, Cheap Nuclear Power”.
Could fly to Mars in a couple weeks, to Saturn in about 3 months. To the moon for a weekend.
Cost to Low-Earth Orbit would be reduced to only ~ $20/kg.
With that we could easily access massive quantities of minerals within the Asteroid Belt, even to the point of possibly terraforming Mars.
Sure, we don’t have access outside of our solar system yet, but give us a few thousand years, we’ll sort it out.
The phrase “at least with current technology” is the key. Of course this is the case.
Indeed, we cannot hope to explore space on any interesting scale without the continuous advancement of technology. Space travel requires tremendously concentrated energy. The author is right that chemical rocket technology does not provide the high energy density needed. We will need nuclear technology if we want to send humans beyond the Earth and the moon.
As for the risk of failure and government’s willingness to tolerate failure, perhaps government is not the best mechanism for space exploration. Government is vulnerable to the pressures of the aerospace industry, which merely wants large expensive projects. The private space industry has shown that it can do what government funded rocketry does but for one tenth the cost. And private industry has never been deterred by the risk of failure.
Ridiculous. Humankind needs space travel, or it will languish and expire in a downward spiral of mediocrity. The current technology won’t limit us, other technologies are already being developed. It won’t be a very long time to do so, either. The only thing keeping us to one planet is political will to use the resources available to us for it.
I dislike the mindset that we should just be good little monkeys and stick to our little jungle because its too hard to cross the desert for what we don’t know. Those monkeys are still in the jungle while the ones that dared found better places and evolved, discovered better tools to survive and so forth. Nothing ventured, nothing gained. Its in the long term interest of the species to be located in multiple places in the Solar System to prevent mass extinction. Yes it might take centuries if the will is low, only decades if it is not though. Fission/Fusion can be harnessed more efficiently, there are developments in solar sail tech, even using magnetic fields as a plasma container can be used as a solar sail. Ion propulsion is efficient, and I’m not giving up on humankind’s ability to toss in a random breakthrough every lifetime or so to make it interesting, either. You seem to negate many possibilities in the same way that your counterparts in the 19th century said balloons were just an interesting toy, mankind would never master heavier-than-air flight and shouldn’t try.
Dare to dream, the alternative is to be a pessimist who gets off on trying to make everyone else like them so everyone can be equally miserable in our stagnant little pond.
Why is why a) it makes more sense to get well established in LEO and on the moon first, and b) why we won’t be using chemical rockets to go further.
They, too, could not carry all their food and equipment with them. They sent out parties ahead of time to lay depots at regular intervals. The party actually making the trip to the Pole replenished its supplies at each depot, both on the way there and on the way back. The depots were sufficiently large that they often did not need it all.
Space depots could easily be unmanned, requiring no life support systems. The orbital mechanics might be tricky, but not beyond solution.
Also, there’s no reason to assume that we will continue to use chemical rockets.
You are completely ignoring the fact that a rocket is not the only way to get to space. What about a stairway made of inflatable cubes? What about a space elevator? What about a bigger version of the Superman ride at Magic Mountain?
Physics may be an obstacle, but there is clearly enough energy in the chemical bonds of matter to fuel a thousand space programs. Once the next generation energy technology is mainstream, the real difficulty will be how fragile the human body is.
I think the real barrier to extended space travel is not physics or chemistry, but our imagination. There are lots of solutions to these problems, and they don’t depend on breaking the ‘laws’ of science. The more specialist people become, the less able they are in ‘thinking outside the box’. All you need is the will, and the answers will eventually emerge, as we have discovered on many occasions in the past. I hope someone archives this article to amuse future settlers on Mars … M. Andrews
I feel compelled to disagree with one of your starting assumptions — the idea that space travel is all about chemistry.
The fact is that chemically-fueled rockets are simply the wrong technology to be using for interplanetary travel. Various types of ion thrusters (some of which are already in use, and others such as VASIMR that will be flight-tested in the next couple of years) are a far better choice. They easily providing a tenfold increase in efficiency over chemical propulsion.
It’s true that ion engines are not suitable for launching from the surface of the earth into low earth orbit. For that first step of the journey we’ll still be relying on chemical propulsion. However, your hypothetical 50-tonne spacecraft could be placed into a low earth orbit using a single launch of a Falcon Heavy launch vehicle, whose first flight is scheduled less than a year from now. Such a launch is likely to cost $100 million, which (while quite a large figure for you and I) is an insignificant fraction of the federal budget (.000025 to be exact, or 1/40th of 1% of the budget). Easily affordable.
Of course, 50 tonnes is actually a low estimate for the mass of such a spacecraft. However, Robert Zubrin’s “Mars Direct” mission proposal examines some realist mass values for a round-trip Mars mission. From what he describes, you could easily maintain a continuous manned presence on Mars at a cost of (on average) two 50-tonne launches each year, which translates to a launch cost of $200 million. That’s still just 1/20th of 1% of the federal budget, or about the amount that the government spends every 7 seconds.
Of course, launch costs are only part of the story — you still have to develop the spacecraft themselves. But through a combination of international cooperation and the engagement of the private sector, this too can be affordable. And there’s no need for it to be a one-way journey.
It’s not about chemistry at all, or even just about physics. It’s about finding the will to do it.
–Bernie Roehl
broehl@bernieroehl.com
Putting a space elevator on the moon would be trivial, and Mars is well within current engineering practices. Earth is the tough nut to crack due to our high gravitational field. In theory it would work, but in practice it would push the limits of possibility. People will keep working on it, though, because it’s so cheap. “As of 2000, conventional rocket designs cost about $11,000 per pound ($25,000 per kilogram) for transfer to geostationary orbit. Current proposals envision payload prices starting as low as $100 per pound ($220 per kilogram), similar to the $5–$300/kg estimates of the Launch loop, although nowhere near the $310/ton to 500 km orbit quoted to Dr. Jerry Pournelle for an orbital airship system.”
Er, yep–chemical rockets (until laws of physics are loopholed) top out with a specific impulse of 450-seconds and that ain’t-a-gonna go away…Of course, if one was permitted to build a nuclear rocket, this would solve the problems this author notes…As for Virgin and similar companies–more power to them, but, on the other hand, the moral values (or possible lack thereof) implicit in a space vacation make that kind of jaunt problematic, unlike pure exploration. (The reason I mention this is that the moment the first space tourist does take off, someone, somewhere, is going to point to a heroic teacher being paid minimum wage, to a starving child anywhere, to a hobo campground within sight of the launch contrail, etc. And rightly so.) Plus, is squirting greenhouse gases directly into the ozone layer for recreational purposes really all that eco-friendly?
With fuel issue, it may happen the same as when scientists first started explaining the Sun’s energy production. They thought that it was just consuming fuel, thus a limited source.
But a little later, they found out that it was an infinite cycle of transforming hellium into hydrogen and then into hellium again.
Numbers changed logarythmically… We shouldn’t despair.
A number of proposed missions involve sending unmanned craft ahead of any manned shot. These would set down various facilities on the planet’s surface ahead of the human part of the mission.
Such facilities would include habitation modules, basic supplies such as oxygen, water, and food, and of course return craft and an automated facility for producing the necessary fuel from local resources. All such facilities could be confirmed to be in place and in operation before any humans were launched. Some proposals have even incorporated centrifugal schemes to provide “gravity” in transit so that the astronauts would still have decent muscle tone upon arrival, and could use more conventional facilities for food preparation, personal hygiene, etc.
This is of course a very simple statement of what would in practice be a hugely complex mission, but impossible? Perhaps not.
Chemical energy is not sufficient therefore space travel is impossible?
Damn it! If only there were other kind of reactions that yield many orders of magnitude more energy than chemical reactions.. Something like, i don’t know, fission or fusion?
The author finds many problems and flaws with the different ways he thinks we could explore space. And then draws the pessimistic conclusion that it will be impossible.
The lesson history should have taught him is that what seems impossible seldom is, it will only take a little longer. My guess is that we humans within a couple of centuries will be able to build a smallish robotic explorer ship that could explore the galaxy. It would have to be able to: launch, fly, identify suitable planets, land, harvest resources, build a copy (or many copies) of itself and then launch the copy. This way we could explore farther and farther away with increasing speed.
If the explorer also carried a biosequencer it could recreate the human DNA fron a computer memory and if it also carried an artificial vomb and a life support module it could raise new strains of human life on all planets it spread to. And possibly edible plants and animals as well.
Apart from the fact that it will take us a couple of generations to be able to pull this off I see few things that will stop us from exploring all of known space. For more on this and some reading tips, search for “Embryo Space Colonization” with Google.
Bob Suede
Electrical is much more practical, and more powerful.
Yes, it would be a massive construction project, and not too likely in the US, but a magnetic induction launcher could be made for non-living supplies to LEO, using only chemical power for final targeting and docking.
An even larger construction would be needed to launch people. But possible (if based in the US it would have to be in the rocky mountain area)
As for travel – the VASMIR (or its successors) propulsion will do for interplanetary use.
Your article implies that all the necessary materials for deeper space exploration have to leave our atmosphere with a single launcher. The Internation Space station took quite a few trips to take it all into orbit and there’s no reason other missions can’t work the same way.
Have we not reached the point in the debate about interplanetary travel where we move beyond the “rocket blasts off from earth with all the supplies needed”?
Obviously we would not send 12 astronauts to Mars on a rocket from earth. We would send the parts to orbit and assemble the craft there, along with the fuel, supplies, etc.
Once all the parts are in orbit we would send the astronauts…likely 3-4 at a time…perhaps leveraging the Virgin Galactic craft. So the Physics piece is all but solved. The chemistry piece is about propulsion that doesn’t require typical fuel…ion drive, solar sails, something new? The clash here is argui9ng 20th century techniques rather than 21st century. We don’t have to fire all that stuff up at one time.
Even moving around the solar system is time consuming. Imagine a space vehicle which could accelerate at one Earth gravity, 35kph per second, indefinitely. In just two and a half minutes it could go from standstill to Mach 5 and cover the distance from the Earth to the Moon. And yet, even under constant acceleration it would take a month to reach the edge of the solar system and it would only be travelling at 5% of light speed. To make that same trip in a day it would have to accelerate a thousand times faster.
So in-system travel in anything smaller than a self-contained cruise liner requires speeds measured in fractions of lightspeed (Impulse Engines in Star Trek). The vehicles also have to be able to reach that speed relatively quickly which means enormous accelerations, which then means some way of buffering the passengers from that acceleration (inertial dampening?) High acceleration also means high energy, unless an exception is found in Newtonian physics. The vehicle would also need some kind of shield to deflect any impacts with any normal matter in it’s path.
It gets worse if you want to visit the stars. Proxima Centauri is 4 light years from Earth and there are less than 50 stars less than 16 light years from Earth. So clearly some kind of Faster Than Light travel is necessary if humanity is going to explore the stars. (Just think of the logistics required for an ocean journey when the next port is 4+ years away!)
But what if we want to visit another galaxy? The nearest galaxy is over 40 thousand light years away! (Actually, that’s less than the distance across the Milky Way, which is ~100 thousand light years.) So if we want to visit anything more than our nearest neighbours, our FTL has to be more than just a simple multiple of lightspeed.
All of this makes me wonder whether there is any chance humanity will ever visit the stars. FTL and near instantaneous acceleration to fractional lightspeed when we struggle to even climb out of the gravity well.
Meanwhile, we are raiding Earth’s storehouse at an alarming rate (7+ billion people will do that). Today’s waste may be tomorrow’s critical need.
Wouldn’t you just assemble the ship in orbit the same way the ISS was built And then land on the planet in question like they did for the Apollo missions? Sounds like a better idea than a one way trip.
I must be missing something because you’re the one with the PhD.
Can’t I use my iRocket or my iBlackhole to also get there?
The limitations presented in this article make a glaringly bad assumption: That any interplanetary trip must start from the ground. Yes, of course anything we do must start from the ground, but the actual interplanetary trip doesn’t have to.
We’ve already got an orbital platform from which to launch an interplanetary mission. Why not make several trips up to said platform, assemble what’s needed there, and take off from there? That lightens your initial load requirements significantly.
Also, along the same lines, all that should be needed to be landed on planet would be the necessities for whatever you’re doing on-planet, plus just enough fuel to get yourself back into orbit. The vehicle and fuel for the return trip need never get any closer than necessary to establish a stable orbit.
I know this is an old argument, or at least it is to me. But the assumption that you simply must start from our planets surface with every single thing needed to get there, land, and get back, as well as the idea that you must land all that excessive stuff on the distant planets surface, is simply a bad assumption. Sure, it requires several lifts, and assembly in space, and significantly more engineering than just putting something together on the ground. However, dismissing out-of-hand the simple possibility of making it happen is folly as well.
Hi, this reads like long-form ad copy from the 1950′s for Virgin’s new business – doesn’t burn fossil fuels in our atmosphere? Really?
What about collecting your own fuel as you go – why does your article completely ignore that as a possible future development in space travel?
IKAROS has a solar sail – it just flew past Venus. And Bussard ramjets still sound… theoretically.. feasible… I think…
Alright, alright, so you’re being very realistic: “Here’s what you can get in your lifetime”, and what not. But would it kill you to end on a higher note, consider future possibilities, open up our imagination…. on a front-page article in Cosmos?
This reminds me of all the people who claimed we would never travel faster than 50mph, 60mph, 100mph, the speed of sound, the speed of light, etc. They were wrong. The key is to have enough people working on the problem. This is why you need to have more children. Expand the human population. There are not enough people yet. We need more people to add to the brain power of working on big problems like this because if we don’t get off this rock and expand into space, other planets, moons, additional stars, etc then we’re doomed like the dinosaurs. There is a astroid out there with our name on it. Let’s get moving.
While your article is quite correct,the energy to lift from the planet’s surface can be avoided by constructing your spacecraft in orbit.
Multi generational ships with fusion power could conceivably make it to other planets over many decades if not hundred of years.
If we limit our imagination we limit our possibilities. Despite physical (and chemical) limits I do believe we must continue to think about travel to the stars.
There are hard limits on how much energy can be extracted from chemical fuels, but there are much less hard limits on how much energy can be put into a particle. Use ion drives for the post-launch portion of the trip. Once you’re in space you can get the acceleration energy from solar energy, or reactors. Granted, you can only cary so much ejectable mass, but at least it goes a lot farther that way.
Only so much energy to be extracted from rocket fuel? Perhaps. I agree that there is no way that any governmental body would fund – perhaps not even allow – such an exploratory suicide mission. If the amount of energy required can’t be changed, then why limit ourselves to chemical rocket fuels? A fission-fragment rocket, once lofted into orbit by a more conventional rocket (even if more conventional means a Dumbo nuclear engine pre-heating liquid hydrogen before it’s burned with liquid oxygen) has the “gas mileage” to build an interstellar probe fast enough to return results in its creators’ lifetimes. Compared to that, visiting the outer solar system is downright practical.
Oh sure, hue and cry, but back in the sixties, the government made, test-fired, and blew up a series of nuclear rocket engines in order to test their safety. Even when deliberately overloaded until reactor components boiled, radiation release was rather minimal, and with relatively little additional work, these could be considered mature technologies. Russia even has a fair bit of experience flying fission reactors to power satellites, with no catastrophic failures to date. With some international cooperation and decommissioned warhead cores, we could reclaim the image of atomic power in the eyes of the public in the eyes of the public. And get our best and brightest back to fly a second mission.
http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion
This is theoretically available using current technology. We could get to Mars much faster than a chemical rocket.
One potential solution: Make a spacecraft capable of supporting human life *indefinitely*
Hard? Sure. Expensive? Of course. Impossible? Probably not.
Wouldn’t it be possible to send robots ahead of manned flights to prepare a hospitable environment for humans? The robots could build housing and some kind of fuel generation plant to facilitate two-way missions. There are still some great advances in robotics necessary, but it turns the hard physics/chemistry limits back into soft technology limits.
There are two assumptions in this article which I consider problematic. First, that nuclear engines won’t be used. Second, that governments will continue to make all space travel decisions (i.e. whether one-way travel will be done).
Space travel is not a dream, but to realize it we’ll have to go nuclear. We’ll have to master controlled fusion and take it with us on-board of our spaceships. Once we have unlimited energy supply up there, we can use it to build gigantic spaceships using materials that are already present in space, as asteroids. Have you ever seen the meteor on display in the foyer of the School of Earth Sciences at the University of Western Australia? It’s cut in half, so that you can see what’s inside, and what’s inside is… pure iron. We can collect volatiles in the asteroid belt too, or by dipping gas collecting probes into planetary atmospheres.
Once we get to Mars, why land on it? Stay in the orbit, and send probes down–on a one-way journey. We can do this from Earth, too, but not in real time. The probes managed from the Martian orbit, can be servo-robots, providing full virtual-reality environment to the operators.
But the first step must be fusion. This is the “to be or not to be” of space travel–precisely so, Alan, that the iron grip of your restrictive regime of chemistry and physics can be broken.
Greetings from Bloomington, Indiana,
Gustav Meglicki,
zdzisiekm@sbcglobal.net
While space travel is difficult given the size of space, is sending astronauts off to oblivion really a good venture? There are going to be breakthroughs in space travel, and the laws of physics are not immutable. Our focus should be on mining resources from the moon, and solar panels in space. Leave the far out stuff for the satellites.
By the way try out this physics site.
Please, forgive my lack of english skills
and the fact that I am NOT a mathematician, physist, chemist – only a ‘dreamer’ ..
Based on what I’ve read and understood about limits, and the idea that we all live into the ’3D’ Euclidean space in term of spacial geometry, here is my ‘dream’:
Regarding our perceptions of lower dimensions, 1D,2D, we know that 2D cannot see its whole 2D ‘surface’ and is restricted by 1D objects like squares composed by 4x1D lines, and 2D objects have no idea about 3D space. So We, cannot see our whole ‘volume’ as well as we cannot have any ideas of the 4D space. Worse:our eyes are 2D sensors which our brain can evalulate ‘data’ into our living 3D dimension such as directions and distances and we can only ‘move’ inside of our volumetric 3D ‘cube or sphere’ just like (assuming there is) a 2D living can only ‘move’ into its 2D surface.
But We, inside our 3D living dimension, can see the whole 2D surface and we are able to create a ‘discontinuity’ between two surfaces and move a 2D object from one surface to another, thanks to the ‘height’ direction of our 3D volume – so that the 2D physical limits do not apply into our 3D volume.
Now, imagine a living object into the fourth Euclidean dimension, which can see our whole 3D ‘volume’ and could create a discontinuity between two ‘volumes’ restricted by 2D borders, make the 3D object travel to another 3D volume through the 4D spacial direction…. So that our physical limits do not apply.: 3D physics such as mass/gravity and (light-)speed limits do not apply.
Since 1D-2D-3D exist in reality, why should be a reason for the 4D and above to not exists as well ??
We exist into the 3D. We cannot realize any living entities into a flat 1D,2D, but we know that a living entity in 3D includes 1D and 2D (breakable limits). Perhaps 3D is the lower limit for a living entity? – What if we could discover a link to the 4D ‘direction’ into Euclidean space in the reality and what defines ‘movement’ of a 3D object into the fourth dimension ?
Why any people says that the 4′th dimension is ‘time’ ??? Time exists into 1D,2D and 3D, but 3D does not exists into 2D,and 2D does not exists into 1D, and time would exists into 4D,and so on ..
the 4D wiki:
http://en.wikipedia.org/wiki/Fourth_dimension
1. Getting out of the atmosphere is cheap after you build a space elevator.
2. Carrying return fuel from Mars is not necessary since advance robots will make it there. (Same for the Moon — lots of O & H there)
3. Necessary supplies are reduced if you make them on the way [but that is a biological solution...]
etc, etc.
Avioding destinations with deep gravity wells leaves lots of other options. Orbital space stations – not limited to earth orbits, moons, asteriods and possibly comets to name a few,
Space elevators.
Push governments and private investors alike into nuclear energy technology, and materials research. A gas core nuclear rocket could easily hop over to mars and back, and leave the equipment for a long term colony behind. The “hard limits” for nuclear powered craft are much much higher then our current chemical concoctions. We know it will work, all that’s left is the engineering to make it happen, and the will for a connected society to overcome our “fear mongering” overlords.
We can certainly launch a 1 tonne lander to Mars. We’ve done that several times now. So we can also launch a 1 tonne capsule full of astronauts to Mars – but the technology that got a lander there we won’t have enough thrust for the food, water, air, etc that the astronauts will need. If that additional mass is 50 tonnes – then why (at least conceptually) can’t we launch 51 identical one-tonne-payload rockets – one full of astronauts and the other 50 full of food and water – and once we’re out there in space, we link them together.
So long as we can build a rocket that can get to Mars with a payload of any non-zero mass, we can get any arbitrary amount of mass there – including enough fuel, food, water and air to get us back again.
There is clearly no fundamental physics or chemistry bottleneck – hence this article is nonsense.
There may be a motivational bottleneck (robots to a pretty good job) and there is certainly a financial bottleneck – but there is no doubt that we could put humans onto Mars and bring them back again if we wanted to.
1. Send robots first, let THEM take the one way ticket and build infrastructure FOR us.
2. There ARE rocket technologies that may be able to overcome the limits of chemical rockets, like the nuclear rocket, and various types of ion drives. The nuclear rocket has some insurmountable issues with spewing enough radiation to kill all life on earth, but ion drives with a sufficiently powerful energy source (like a fusion reactor) might be possible.
The article is absolutely true for chemical rockets – they are near theoretical efficiency. However, other forms of propulsion can do far, far better. Nuclear and/or electric propulsion, e.g. NERVA, VASIMR have specific impulses around two orders of magnitude greater than chemical rockets! Other proposals such as a giant gun (e.g. Quick Launch Inc.), power beaming, or solar sails, that get their energy from the ground (rather than carry it aloft) bypass the limits of the rocket equation – limits that your article takes to be as absolute as the speed of light. They’re not.
I’ll let Peter Diamandis do the rest of the talking (from his Ted talk on “our next giant leap”)
“We know 20 million dollars today, you can go and buy a ticket [to Low Earth Orbit], but how cheap could it get?
“Let’s go back to high school physics here. If you calculate the amount of potential energy, mgh, to take you and your space suit up to a couple hundred miles, and then you accelerate yourself to 17,500 miles per hour. Remember, that one-half MV squared — and you figure it out. It’s about 5.7 gigajoules of energy. If you expended that over an hour, it’s about 1.6 megawatts. If you go to one of Vijay’s micro-power sources and they sell it to you for seven cents a kilowatt hour — anybody here fast in math? How much will it cost you and your space suit to go to orbit? 100 dollars. That’s the price-improvement curve that — we need some breakthroughs in physics along the way, I’ll grant you that.
“But guys, if the — if history has taught us anything, it’s that if you can imagine it, you will get there eventually. I have no question that the physics, the engineering to get us down to the point where all of us can afford orbital space flight is around the corner. The difficulty is that there needs to be a real marketplace to drive the investment.”
In summary, the physics and chemistry are against us for chemical rockets, yes. For more futuristic space transport, for both humans and cargo, to orbit and interplanetary, they both point to an optimistic future. I’m more worried about paying for it all.
You do mention ‘with current technologies’. However, there are technologies that could work that we could build now, if we just had the reason.
Space elevators, for instance, to get from ground to orbit. Solar sails to get from Earth to Mars, or perhaps a fusion/plasma drive. Look at the Orion project.
http://en.wikipedia.org/wiki/Project_Orion_%28nuclear_propulsion%29
The energy costs can be mitigated, worked around, or overcome. It simply takes ingenuity. Remember, when the theory of gravity was proposed, we couldn’t fly, and at the time the technology didn’t exist to make it happen. 50 years later people were experimenting with balloons. 225 years later humans used powered flight.
It takes time, and creativity. But I don’t doubt we’ll overcome. People are always doing crazy things that others say they can’t.
The author completely discounts any form of nuclear propulsion or nuclear-electric propulsion. The ISP of even the proven and tested NERVA engine was almost double what the SSME are. 800+ n/secs vs 450 n/secs. We will know how to make VASMIR engines in the next 10 years.
What’s more, if the late Dr. Robert W. Bussard’s team at EMC2Fusion.org comes through, then we can power all the above with clean, safe aneutronic fusion power.
Please remember Clarke’s First Law:
“When a distinguished but elderly scientist states that something is possible, he is almost certainly right; when he states that something is impossible, he is probably wrong.”
How about Project Orion-class propulsion? It is within our current technological grasp, and Moon-based launch sites would prevent most of the harmful effect of fallout.
Yes, chemistry is a harsh mistress, but nuclear propulsion and energy are easily powerful enough for inner system travel. E=MC^2 makes your life so much easier if you just get over irrational fears of the nuclear bogey man.
I find it increasingly unlikely that human space travel in specialized meat-capsules is plausible. I think, given the impressive advances in computing and brain imaging that we will be able to copy our consciousness into machines that will then do the travelling. Solid state universe exploration seems more plausible.
Basically, I think it’s more likely we will invent AI before we invent galactic-scale human space travel.
Finkel seems to have the unstated premise that we must carry all materials for interplanetary human flight up from the Earth’s gravity well. In principle, the only thing that needs to come up from Earth is the humans. Robotic mining and manufacturing could produce all the needed matériel from the moon and asteroids and put them in place throughout the solar system to service human travelers.
While very slow to begin, the ability to self-replicate would over time create a very robust robotic supply chain.
Space has a generous allowance of small pieces of mineral, the speed of which is random, though around 50,000 mph may not be unusual. When these encounter a vehicle of any kind, they pass straight though. Imagine bullet and tin-can, but much faster.
All of your statements assume space travel will use rocket fuel. What if we use nuclear power ? Then your above article is false. What happens if we figure out fusion(not that crazy of an idea)? If we could alter particles on a sub attomic level chemistry is not a limiting factor.
I think you’ve got your blinkers on! You’re thinking of launching all this cargo from Earth’s surface in one go, when that’s not the only way. We can stage components of the expedition in space, attached to the ISS and then launch them to Mars from there. Earth’s gravitational pull is much less at those heady heights.
We could even launch the components individually all the way to Mars and only send the human cargo once it was confirmed that everything was already in place.
How about a bit more lateral thinking before penning an article??
Your article is interesting. However, it is faulty because of either hubris in scientific knowledge or a misunderstanding in what scientific artifacts represent. Today, the hypothetical that we may not be able to space travel is based on logic using our current knowledge of nature, but that may not always be unless you believe we are at the pinnacle of scientific knowledge.
Science is a knowledge process and nothing in science says that the knowledge generated is absolute or immutable(although we would like to believe we have found unalterable truths of nature.) Scientific knowledge is highly coincidental with nature at best. However, science has humility built into it that allows modifying theories because we observe new behavior in nature that contradicts scientific knowledge. Is this process still alive today? Have we found the Higgs particle – a mythological particle to date?
For instance, is it possible for humans to identify phenomena incorrectly and still develop knowledge that allows us to engineer with those ideas dependably? I believe this is what gravity is. Do we have a better understanding of gravity today than when Newton invented the concept? Is the concept of gravity any more useless because we do not have a basis in nature for it?
Science allows us to develop lots of knowledge around a concept we really have no knowledge about. Isn’t quantum mechanics this same type of science? I do not believe atoms are actually as they are when we draw them on a blackboard. I do not believe atoms can tunnel through matter(which is supposed to be physically impossible, but theory models quantum behavior this way.) Does a scientific model need to exist in reality or is it more important that the model deliver its conclusion dependably? Is understanding of space travel or space locomotion any different than gravity or quantum mechanics? If not, then how can we extrapolate a future for it?
So, I wouldn’t be so quick to conclude space travel is impractical or box science in and say that there will be no more ingenious ways for humans to engineer nature because these are “hard” rules. It just takes a better genius to innovate with nature.
This articles fails to understand that chemistry is not the only source of energy available to propulsion, even short term. Nuclear energy (fission or pulsed fusion), antimatter recombination, light propulsion, batteries / ultracapacitors, beamed power used to accelerate a material, … There are many possible propellants outside electronic reaction in chemistry.
With space elevators it will be much easier/cheaper to get things into orbit. From there a space faring infrastructure can be built to support space travel. We could build ships up there, have refueling stations etc etc. We need space elevators
We already have built a space station in low orbit using many chemical rocket trips to deploy and assemble the components in space. Rather than lift off from Earth and go straight to Mars, you can continually lift spacecraft components into orbit. Assemble your massive Mars ship in orbit. This gets around the mass limitations of a single rocket launch. From that point you set off for Mars.
As for landing on Mars you do it in a similar manner to the Moon landing. Leave the mother ship in Mars’ orbit and deploy a landing craft. Getting off Mars would be much more difficult than leaving the Moon although there is still lower gravity and a thinner atmosphere than on Earth. In any case a Mars return vehicle to boost our intrepid astronauts could be put on the surface whether it was the same vehicle they used to land or a specialized lift off vehicle.
The problem isn’t chemical rocket capacity. The problem is that funding a mission like this is an extraordinary economic cost without any real benefit. As you mentioned exploration is much, much cheaper to do with robots. Not to mention safety. If our human space program remains as risk averse as it is now you can pretty much forget us ever making it anywhere. It will be interesting to see if even an accident on a commercial non-orbital rocket will stifle that market.
When mankind set to crossing the oceans it was not just for exploration but for possible gains. If the “new world” had been a giant lifeless desert one wonders how many trips the European countries would have funded. A modern day trip to Mars seems just like that, a hugely costly endeavor to a barren world who’s riches are limited to those of scientific understanding and curiosity. An itch that’s much easier and cheaper to scratch with our robot rovers than it is with human beings.
Two words change your whole equation: Space Elevator.
I still have hope.
(1) Space Tourism seems the real waste of energy and it also relies of those alleged fantasies of deeper travel into space. How can you have any interest in space at all if you don’t see a future in it? On the positive side, Space Tourism can fund ingenuity to see where it might take us with or without faith that it can take us to other worlds. And if we are burning renewables, such as hydrogen/oxygen, then it isn’t really wasted energy or environmentally damaging (depending on how you split water into hydrogen/oxygen).
(2) I really don’t think any of the advocates of a one-way trip to Mars suggested living a few months and then committing suicide. They simply suggest that life expectancies would be reduced with higher levels of radiation we are not evolved for and the limited access to medicine. The lander in the north and now re-analysis of the two viking landers’ data tell us the soil is rich in perchlorate–which are very rich in oxygen. We also know of glaciers in the equatorial regions which must be fresh water ice. These have been found more than two kilometers thick. After extracting the perchlorate, the soil should be ideal for farming. One could melt-out a large habitat in fresh-water ice well protected by a layer soil over the top from radiation. Magnetically levitated wind turbines require extremely low maintenance. LED lights do not burn out and they are available in sun-spectrum good for growing plants. Perchlorate is good for brick making, smelting metals, and a powerful rocket fuel.
(3) The space-elevator concept seems to have passed every test of viability (except for the reliability of the climbers), thus far, too.
(4) I see mankind moving more into space then only other worlds. The rapidly increasing chances of microbial life being common in the universe raising the question of potentially huge risks when populating other worlds, like Mars. But these might be overblown–it might be that our natural defenses are generalized enough to render them harmless.
(5) Imagine instead, building cylinders with soil and vegetation growing on the inside walls. The spin simulates gravity. An artificial sun moves across a cable down the center and returns as an artificial moon. Artificial rain also sprinkles down from this. It would soak through the soil and into rivers from which they could be collected again for rainfall.
Mankind could be saved in this way. With an unchanging environment can we ultimately prevent our offspring from evolving into something else.
Other alternatives includes biological immortality–using gene therapy to increase our cellular rate of repair to above the usual rate of decay (already done in experiments with mice and worms) or to replace the telemeres on the ends of DNA strands directly.
Or yet another approach might some day be to copy our minds into computers and let them live out a virtual eternity in a virtual world, perhaps physically orbiting the sun. It might very well be that all memory and behavior is determined by the shape and interconnections of neurons. A new approach to map all of this is possible by tracking the movement of water molecules at very high resolution.
It would be weird to think of a copy of one’s self as a continuation of one’s self but the copy would, in theory, believe itself to be you. It would contain all of your memories, beliefs, and behaviors. If you were it, it would be weird to think that the original was you.
This is a current science article? I cannot believe the uninformed, myopic negativity the author exhibits in this article. First of all, current deep space, and even orbital craft are now very often designed and fitted with ION propulsion, which ejects it’s fuel at millions of degrees, with high focus, efficient vector-thrusting capabilities, and has comparatively enormous thrust/weight efficiency. NOT chemical. Ion propulsion is becoming ever more powerful and efficient, particularly as those serious about such matters continue to increase funding for it.
As for lifting large amounts of cargo into orbit, that’s simple. Build an orbital elevator. The technologies are all there now, we just have to spend the money to do it.
Come up with a more interesting subject for your article next time. How about finding out what the possibilities are for using the meta-materials that make up current “cloaking” tech for the creation of shielding for spacefarers from high energy x-rays etc.? What about combining that idea with recent advances in meta-materials use for solar panels, work with both nano-carbon fibers and high temperature super-conductors to conduct electricity. Then, if the manufacturing process could be worked out, you could build skin for spacecraft that not only shields occupants from high energy photons, but uses those same intercepted photons to power conductive fibers woven into the underside of the material to generate powerful, but highly localized magnetic fields that would at least help to deflect or slow down the relativistic bits of matter that are cosmic rays from crew members.
All the pieces are there for us to pick up and use. Why are so few trying to actually put them TOGETHER, rather than pick apart antiquated (though sadly commonly currently used) technologies? All for the seeming purpose of making the case for doing nothing, and dying like too many rats in a cage? We as individuals will die. Nothing changes that. But before we do, we have the chance to ensure that the human race will live forever. You may call these things fantasy, but I’m typing this on a laptop with wifi, on a forum, originally modeled after the “Letters To the Editor” columns of old newspapers, that is a wholly informational construct. And it can be viewed by billions around the world. But when I was a child, our house had a rotary phone. What you call fantasy, I call brainstorming.
We shouldn’t be too practical. It is essential we keep on dreaming on conquering space. It is true we don’t have the needed technology for that, today. But when we keep our aspirations high, and keep on struggling against nature’s limitations, we sure to get a solution/breakthrough sometimes in the future (even if it takes another 500 years).
There are steps that can be done even today – space stations, better space shuttles, lowering costs of space travels, human colony on the moon/mars. But it is just the beginning.
Things that seem impossible today, can become trivial in several decades.
What century are you from, dear time traveler? Transforming helium into hydrogen? That would consume energy! Infinite cycle? Hell no! Stars aren’t infinite, our sun only has a lifespan of 10 billion years, it will be gone in 5. Of course it’s consuming fuel – in a magical process called fusion, it turns hydrogen into helium to release energy. There is NO reversing the fusion, as that would CONSUME energy.
Who realistically thinks that we can go to Mars or even NEOs with EXISTING technologies?
Was anyone suggesting we could go to the moon in 1959 with existing technologies? Articles like this remind me of all the naysayers that told the Wright Brothers that we would all have wings if we were meant to fly.
The thing is, you even ignore existing technologies that, while not ready for prime time, do in fact work. The VASIMR motor comes to mind pretty quickly. Then there are nuclear rocket motors that were first built in the 1960s. But why stop there? A space elevator my be practical within our lifetimes. Inflatable habitats are making spacecraft more lightweight and safer from impacts and possibly radiation. New research is showing that even a weak magnetic field may be able to protect humans from solar particles. Not a single one of these technologies are pie in the sky dreams.
There is really only one MAJOR barrier to interplanetary exploration. Go look in the mirror because it is us. We lack the political and fiscal fortitude to get moving. We are too comfortable on this rock to get moving. In the 1960′s Americans were VERY uncomfortable with the Soviet threat and superiority in anything. Kennedy’s death put even more focus on his lunar goals. We have to get uncomfortable again in order to get out of our lounge chairs and get back to exploration.
Alan is correct. The best chemical reactions give an exhaust velocity of about 4.5 km/sec. You need twice that much to get a substantial payload into LEO.
However, chemical reactions are not the only way to heat a gas and hydrogen heated to 600 deg less than the melting point of tungsten gives more than twice the exhaust velocity of the SSME.
This wasn’t possible to consider until recent times when high power semiconductor laser diodes came on the market.
The air breathing Skylon used for a “first stage” has an equivalent exhaust velocity of 10.5 km/sec until it runs out of air at 26 km and 2 km/s. Switching to laser heated hydrogen at that point would put 1/3 of it’s takeoff mass in LEO–about 50 tons.
It does take a lot of laser power, about 6 GW.
Keith Henson
The best chemical reactions give an exhaust velocity of about 4.5 km/sec. You need twice that much to get a substantial payload into LEO without staging (which is very expensive).
However, chemical reactions are not the only way to heat a gas and hydrogen heated with lasers to 600 deg less than the melting point of tungsten gives more than twice the exhaust velocity of the SSME.
This wasn’t possible to consider until recent times when high power semiconductor laser diodes came on the market.
The air breathing Skylon used for a “first stage” has an equivalent exhaust velocity of 10.5 km/sec until it runs out of air at 26 km and 2 km/s. Switching to laser heated hydrogen at that point would put 1/3 of it’s takeoff mass in LEO–about 50 tons of rocket plane and 50 tons of payload..
It does take a lot of laser power, about 6 GW, but we can draw that off the grid (in a few places).
Keith Henson
Once the problems of deep space travel are solved: propulsion and cosmic rays, then we will be able to go somewhere. Until then, there isn’t much point in venturing beyond our moon and maybe Mars.
We already have a functioning spaceship called Planet Earth that has been stress-tested for a few billion years. If we can’t keep that one maintained a bit better than we are at present, we’ll likely never establish ourselves in outer space either.
Kirk on Earth
If we focus on keeping alive on spaceship Earth, we might last long enough to conquer the many obstacles for deep space travel. Until then, our excursions off this little rock are at best an expensive hobby.
With current reaction engines you are exactly right. Mass times acceleration will equal a finite thrust. Nukes are just one way of upping the thermodynamic energy to accelerate a finite mass. IMHO however full scale space travel faces many hurdles. Some technological, some financial, some political and sociological. No it’s not impossible any more than getting a ride up to the I$$ but is it sustainable.
Similar to living at the bottom of the ocean, the cost (human productivity) means only a few will be able to go at the expense of the many. How long will that fly? To what benefit? It’s not exactly like exploring the new world where the tools that took you across the lake could be upgraded to take you across the sea. What about the psychological effects of prolonged confinement in small vehicles? The very real radiation danger? The incredible energy release of colliding with even a small space rock?
I agree with the reader who said in so many words that we need space based vehicles that don’t enter deeply into planetary gravity wells. Like ocean liners they stay in the environment they are meant to operate in. IMO the technological deficit we face is a challenge more than a confinement that we should accept.
The small-minded have ever said ‘stay at home, close the doors and windows, be safe.’ Why? You’re dead anyway. Might as well do something.
once the space elevator becomes operational, you could theoretically have enough fuel for space travel there and back, since the getting out of earths gravitational field variable is eliminated.
Alan, I will do everything in my power to find you in 30 years, with this article in hand, and hold it directly in front of your face. Most likely, I’ll have a good laugh at your expense as I re-read the article and underscore how everything you said was impossible turned out otherwise. You sound like every pessimist there ever was with regards to technology.
“Alan Finkel is a neuroscientist and entrepreneur” — neuroscientist and entrepreneur talking about limitations of physical and chemical laws claiming something impossible – that’s the best joke I’ve had in weeks. A bunch of empty statements; provide at least one number to back your claims? No.
Certainly human space exploration is possible not just with new technologies like ion engines, nuclear propulsion, or solar sails, but most certainly with chemical rockets (!). The main problem with the manned exploration beyond the Earth orbit is not propulsion, but sustainable space habitats and space hazards (such as radiation).
Solar satellites can provide plenty of power. The most portable energy would be antimatter. Solar powered antimatter factories. Think about it.
So it is not really easy to travel lots of with monkeys in a can to Saturn or Mars. Well boohoo, we’ve known that for decades. So what do we do instead?
1. we take “a few thousand of people’, largely old and highly trained volunteers, and let them construct industrial infrastructure in the earth-moon system. Most would die from radiation sickness, still many more would volunteer. Something like soldiers, but now people who actually know what they are getting into and actually build stuff rather than tear apart. These pioneers would construct mass drivers on the moon using telepresence robots. They’d construct plush O’Neil habitats whose designs were presented to US congress and rubberstamped as “great idea!” in the 1970s. This we could start doing now, at a cost of ‘only a gulf war a year’. If we started now, for real, we’d be giving all oil exporting countries a big finger by 2025. How? THIS WAY : http://khanneasuntzu.wordpress.com/2010/06/19/the-acronym-everyone-should-know/
2. When we have the energy thing sorted out, say around 2040, we let desperate and crazy eed wild-cutters head out of the earth-moon system using solar-cell propelled ion propulsion slash magnetic railgun drives. Many will die along the way. More would volunteer. Again, all this is technology known in the 1960s. It isn’t sexy roaring “pressed in your seat” high G acceleration a la Buck Rogers, but these 0.01 G sure adds up over weeks and months. And those asteroids are worth the effort – the more industrial base you have in near earth orbit, the more you can process, the more you can start adding. Yes that’s exponential growth curves mister.
3. Who cares that a voyage to the asteroids takes years? There are many asteroids, many intermediate stops and much profit to make along the way. We don’t have to go there immediately. Let Debbie first do Jersey Shore before she goes all the way to Vegas. Baby steps…. It worked for Magelhaez, it’ll work for the Picards as well. What’s this obsession with fast phallic penetration of the solar system? CHILL OUT!
4. thanks for the Red versus Blue reference
http://khanneasuntzu.wordpress.com/2010/09/27/red-versus-blue-the-dance-of-death-democracy-entitlements-populists-and-oil/
5. This is the site I made on this topic and the presentation I did about it in Milan last year, fwiw. : http://terasemcolony.wordpress.com/
I think he is out of touch with current physics and needs to go back to physics 101 and learn something if this is all he can come up with. This article is full of opinion and assumptions based on physics so limited and not inclusive of new and not so new developments. Ion and solar sail technology, air breathing rocket technology, the real possibility of space elevators in the next few decades, nano propulsion technology, etc etc are pretty basic evidence based literature fare these days. Chemical rockets are useful but other technologies may limit their use in the future and there are new scientists and engineers determined to push for this. Someone was correct in mentioning the need for habitat research and development for long haul human flights but I would also contend as many others have that nano robotic long haul space flights could provide valuable information at fractions of the cost of much larger vehicles. All options should be open.
String theory (and all other theories involving hidden dimensions)
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By Martin J Sallberg
If some brave astronauts want to visit the Mars, the outer planets, a wandering planet in deep space, and eventually the nearby star systems, then someday someone will go. Its in human nature to want to visit new places, and anything we can see but not reach piques our interest. Given the size of space, it is an endless frontier, so we won’t run out of destinations any time soon. By the way, the laws of physics are immutable- its simply that we don’t understand the laws of nature perfectly yet.
As for the immutable laws of physics and chemistry, there is another power source for space travel- nuclear energy. Fission rockets may be able to give the space program an early boost, but nuclear fusion rockets will open the doors to space in a way never before seen. A fusion rocket could superheat water for reaction mass, allowing it to take off of planets easily. An even more drastic technique is nuclear pulse propulsion. In the far future, total annihilation drives could make starships practical.
A larger problem for starships is reaction mass. All rockets need propellent, and even the most powerful rockets need an unacceptable amount to accelerate to near light speed. Then you need to decelerate if you actually want to stop at another star- not just fly past at nearly the speed of light- so you need to more propellent. But you need to accelerate all the propellent you need to decelerate at the trips end, so you need more for the outgoing stage of the trip- the problem snowballs and you end up with the planet Jupiter in tow. This is a serious problem, even for ships that only try to reach a speed of say 30% light speed. That is why most designs today are almost all propellent and would explore the universe in a very tedious manner, reaching only a fraction of the speed of light at best.
So, a means of propulsion that does not consume propellent is needed, preferably one that can propel a ship to enormous speeds. This seems to run counter to the Law of Conservation of Momentum, but some scientists have looked into this- Google the “breakthrough propulsion physics project” and “Mark Millis space drives”. Ideas like warp drives, gravity control, and control over inertia might be able to do this- but such concepts are speculative at best.
Leave the asteroid mining and solar panels to power companies and miners- eventually explorers will want to travel much further. If space technology develops to the point where it is feasible to mine asteroids, than scientific spaceships and explorer ships will be built as well.
Christopher Phoenix
Technology will continue to advance. What may seem impossible today will be possible tomorrow. Man will one day explore our entire solar system and perhaps beyond. The advances in technology will continue exponentially.
Money would then become an issue. Each space flight would cost over a billion dollars. . and NASA has been under extreme budget cuts. . .
We already have the technology to fly distant galaxies – just ask the US Military. It is being kept secret but luckily we have people on this earth who are trying to reveal the truth about this technology. All will hopefully be revealed soon!
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Given ALL OTHER OBSTACLES mentioned were somehow overcomed…there is STILL the DANGEROUS problem of the VAN ALLEN RADIATION BELTS..surrounding our planet!! So far to THIS DAY these have/can ONLY been traversed by UN-MANNED exploratory craft !! NOT by LIVING beings..HUMAN or Otherwise!! THIS has been the “GREATEST” barrier to feasable space travel by HUMAN BEINGS and until remedied…”ALLWAYS WILL”!!
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You are a nut. There is no such technology.
I think you might want to take a look at WHY Dyson proposed Project Orion. He did it because he couldn’t think of any other possible way for humans to conduct deep space exploration on a reasonable timeframe.
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I have read personally a big article on the internet from one prominent physicist and engeneer who used to work for NASA for long time. His knowledge is undeniable, both practical and theoretical. He said exactly:
“THEY have already all means for cosmic travel to nearby stars and even galaxies…”
I can’t forgive myself why I didn’t copy this article and been searching for it ever since, because this is valuable info – not a “ufo” speculatiion.
If it so, why “they” don’t use it?
There are many reasons for it where perhaps military one is most important.
One thing anyone could notice: US gov’t and NASA all of the sudden are cancelling all american human endevoars to space (instead, they are sending robots and turn to asteroids?) with perspective of abandoning even ISS! What is this? Neil Armstrog personally called it a “shame”.
Logical question is: Why they are doing this, after so many decades of efforts and money put into space exploration and even sending humans to Moon?
The answer is simple: why should be continuing with old technology, when these big monies can be put into this planet, country and american people – crumbling economy, poverty reduction, not to mention cost of wars and who knows, preparing for future ones.
Why, when “they” already have new technology who is far advanced, imensely faster and do not pose threat to human lives (as it was Space Shuttle, for example).
Building “new rockets” (with old chemical propulsion), sending robots and mining asteroids is a pure bluff for “their” nation and potential “rogue” ones, that something is happening, while the real TRUTH is hidden.
So, appologize for your rude comment when you don’t know nothing (as doesn’t know author of this stupid article, either).
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I’m still learning from you, but I try to reach my goals. Since then enjoy reading all the information that appears on your blog.Keep come. Loved it!
home decor accessories
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