In 1961, Yuri Gagarin became the first human being to reach outer space. Eight years later, Neil Armstrong and Buzz Aldrin made it to the surface of the moon. And that is as far as any of us has ventured.
Apart from the mundane problems of budgets and political will, the major roadblock is that our dominant space-flight technology – chemically fuelled rockets – just isn't up to the distances involved. We can send robot probes to the outer planets, but they take years to get there.
And as for visiting other stars, forget it. As an example of why, the Apollo 10 moon probe is currently listed as the fastest manned vehicle in history, having reached a maximum speed of 39,895 kilometres per hour. At this speed, it would take 120,000 years to cover the 4 light years to Alpha Centauri, the nearest star system.
So if we want to explore the depths of deep space and journey to Alpha Centauri and beyond, we're going to need some new technologies. Here, we look at 10 of the most intriguing.
The technologies range widely in their plausibility. Some, we could more or less build tomorrow if we wanted to, while others may well be fundamentally impossible.
Ion thruster
Conventional rockets work by shooting gases out of their rear exhausts at high speeds, thus generating thrust. Ion thrusters use the same principle, but instead of blasting out hot gases, they shoot out a beam of electrically charged particles, or ions.
They provide quite a weak thrust, but crucially they use far less fuel than a rocket to get the same amount of thrust. Providing they can be made to keep working steadily for a long time, they could eventually accelerate a craft to high speeds.
They have already been used on several spacecraft, such as Japan's Hayabusa probe and Europe's SMART-1 lunar mission, and the technology has been improving steadily.
A particularly promising variant is the variable specific impulse magnetoplasma rocket (VASIMR). This works on a slightly different principle to other ion thrusters, which accelerate the ions using a strong electric field. Instead, VASIMR uses a radio-frequency generator, rather like the transmitters used to broadcast radio shows, to heat ions to 1 million °C.
It does this by taking advantage of the fact that in a strong magnetic field, like those produced by the superconducting magnets in the engine, ions spin at a fixed frequency. The radio-frequency generator is then tuned to that frequency, injecting extra energy into the ions and massively increasing the thrust.
Initial tests have been promising, and if all goes well, VASIMR could be used to take humans to Mars in 39 days
(see illustration).
Plausibility: just a few years away
Nuclear pulse propulsion
If some of the ideas here strike you as a little unlikely, this one will seem downright reckless. The notion here is to power your spacecraft by periodically throwing a nuclear bomb out of the back and setting it off.
Nuclear pulse propulsion was studied seriously by the US government's military technology agency DARPA, under the code name Project Orion. The aim was to come up with a design for rapid interplanetary travel.
The design DARPA came up with was huge even by today's standards, and was built to be a giant shock absorber, with heavy radiation shielding to protect the passengers.
It seemed workable, but there were concerns about fallout if it was launched in the atmosphere as planned. The project was eventually dropped in the 1960s when the first nuclear test bans came into force.
Despite these worries, the Orion design remains one that could be built using existing technology, and some researchers are still coming up with new approaches to nuclear pulse propulsion. Theoretically, a nuclear-bomb-powered ship could reach up to 10 per cent of the speed of light, allowing a journey to the nearest star in about 40 years.
Plausibility: perfectly possible, if a tad hazardous
Fusion rocket
Nuclear pulse propulsion is far from the only space-flight technology that depends on nuclear power.
For instance, nuclear rockets could use the heat from an onboard fission reactor to expel gases, providing thrust. But in terms of power, these pale in comparison to fusion rockets.
Nuclear fusion, in which the nuclei of atoms are forced to join together, could produce vast amounts of energy. Most designs for fusion reactors drive the reaction by confining the fuel in a magnetic field, using a device called a tokamak.
Unfortunately, tokamaks are prohibitively heavy, so designs for fusion rockets tend to focus on another method of triggering fusion, called inertial confinement fusion.
This design replaces the tokamak's magnetic fields with high-powered energy beams, usually lasers. These blast a small pellet of fuel so intensely that the outer layers explode. This in turn crushes the inner layers, triggering fusion. Magnetic fields could then direct the resulting hot plasma out of the back of a spacecraft. Hey presto: a fusion rocket.
If you would like to reuse any content from New Scientist, either in print or online, please contact the syndication department first for permission. New Scientist does not own rights to photos, but there are a variety of licensing options available for use of articles and graphics we own the copyright to.
Have your say
Don't Be Funny, Michael
Mon Dec 21 10:13:03 GMT 2009 by Polemos
http://eschatopedia.webs.com/eternalyouth.htm
By the end of such an interstellar journey, the vehicle, having been pierced by billions of micrometeoroids and cosmic particles, will resemble the ghost of Hamlet's father.
Don't Be Funny, Michael
Mon Dec 21 10:58:08 GMT 2009 by Polemos
http://eschatopedia.webs.com/eternalyouth.htm
This is an excerpt from an official NASA report: (long URL - click here)
The post is split in two parts.
Part 1.
"4. IS INTERSTELLAR TRAVEL FEASIBLE?
I think the answer to this is probably yes. Whether or not the cost and hazards of interstellar flight are outweighed by the need or desire to engage in such activities is quite another matter. As discussed in the Cyclops Report, (Oliver and Billingham, 1973) the best you can do and still obey the known laws of physics is a hypothetical, 100% efficient, relativistic photon rocket driven by matter/antimatter annihilation. In a round-trip powered flight to the Alpha-Centari system (4.3 light years) at approximately 0.7c, a spaceship weight on the order of 1000 tons might be required to support a reasonably sized crew for what would be at least a 13 year (ground elapsed time) journey. At this speed, the mm round-trip mass ratio (fully fueled to burnout mass) would be about 34. This means that 33,000 tons of matter/antimatter fuel would be required, delivering a total energy equivalent to the electrical energy consumption of the entire United States for over 300,000 years!
Perhaps a more reasonable voyage might be a 10 light-year trip to the nearest, single, solar type star at a much slower speed in order to reduce the mass ratio penalty. At 0.2c the mass ratio for a round-trip voyage would be about two (fuel mass approximately equal to payload mass). Since this involves a much longer trip time (approximately 100 years), our spaceship would have to be much more massive, perhaps 10,000 tons or more, even if the life support was a closed system. The frontal area for a space ship of this mass might be as much as about 100 meters by 100 meters. In a 10 light-year distant round trip, this frontal area would carve out a volume in the interstellar medium equivalent to approximately twice the volume of the entire Earth.
What about the interstellar dust hazard? What might it be and how might we be able to protect ourselves? We know very little about the distribution and density of particulate flatter in the interstellar medium except at the very small end, interstellar grains, as determined by the absorption of star light. It is interesting to note, however, that the density of these picogram particles in the interstellar medium is roughly equal to the density of these same size particles in the interplanetary medium near Earth. From a variety of ground-based and space borne measurements we now have a fairly good indication of the size distribution and space density of particulate matter in the interplanetary medium. Our Pioneer 10 and 11 missions to the outer solar system and beyond were the first and only spacecraft to carry micrometeorite detectors beyond the orbit of Mars. These detectors, sensitive to particles approximately a billionth of a gram and larger, indicated that the flux of these particles was not associated with the asteroid belt but instead was omnidirectional and independent of distance from the Sun out to 18 AU (Humes, 1980).
Don't Be Funny, Michael
Mon Dec 21 10:59:21 GMT 2009 by Polemos
http://eschatopedia.webs.com/eternalyouth.htm
Part 2.
"It is intriguing to consider the possibility that the size distribution and space density of particulate matter that we find in the
interplanetary medium is the same as would be found in the interstellar medium. However, even if it were a order of magnitude lower in the interstellar medium, then the largest particle which we would have to contend with in our 10 light year round trip voyage would be about 100 grams (a large hail stone). At 0.2c, a 100 gram particle has a kinetic energy equivalent to the explosive energy of a 40 klloton bomb!
Even neglecting hypervelocity impact ejecta and considering only the conversion of kinetic to thermal energy, a shield the equivalent of a 10 meter thickness of solid tungsten would be required. Such a shield covering the front of our spaceship would weigh in excess of two million tons. Since the shield must be part of our payload (thus making our spacecraft weight rather insignificant by comparison), a mass ratio of two also requires a matter/antimatter fuel mass of two million tons. This is equivalent to 18 million years of U.S. electrical energy consumption, or about 90,000 times our present GNP.
The use of a cloud of dust particles injected upstream from a spaceship (Bond et al., 1978) has also been considered for shielding purposes. An inverted cone-shaped cloud with one microgram ice particle per cubic centimeter (a one microgram particle at 0.2c is equivalent to approximately 0.8 pounds of TNT) with a base diameter of one kilometer located 300 kilometers out in front of our spaceship would weigh about 86,000 tons, which is significantly less than our solid shields However, this type of shielding would require long periods of no acceleration and in addition, would be subject to constant dissipation by external forces. By far the largest would be the forces generated by the constant impact of interstellar grains on the forward portion of the shielding dust cloud. For a one kilometer diameter ram area, this would be about 100 megawatts. This might require the equivalent of a complete replacement of the cloud every few weeks or at least every few months. For a 100 year journey, however, this cloud could not be replaced anymore frequently than about once every four years (which seems highly unlikely) in order to keep the total required mass for the dust cloud shielding less than that required by a solid shield.
5. CONCLUSIONS
The bottom line of all this Is quite simply that interstellar travel is so enormously expensive and/or perhaps hazardous, that advanced civilizations do not engage in the practice because of the ease of information transfer via interstellar communication links.
They are not here, therefore they are either not there or they are there and they're all talking to one another."
You can use the ice to bulk up the tungsten as both shielding mass and fuel mass. Since you won't need much shielding at the end of your deceleration
A more accurate conclusion would be, "given the particular conception of interstellar travel I have outlined, it is indeed too hazardous for a civilization to engage in."
"Advanced Civilizations" are called advanced because they probably have better ideas than we currently do. For instance, your post at no time mentions the possibility of active sensing (laser or radar) for the detection and avoidance of interstellar grains, particularly the largest ones. The success of this type of near-term technology alone alleviates the concern of your entire post.
This comment breached our terms of use and has been removed.
Polemos, there's a reason scientists use more recent literature. By recent, I mean <5 years old. 10 years old is pushing it.
The only reason to bring a piece of literature older than that is if it were a truly landmark article.
So my advice: STOP PRESENTING DATED LITERATURE!
Especially where technology is concerned.
Don't Be Funny, Michael, Funny?
Wed Dec 23 21:47:09 GMT 2009 by Dennis
http://freetubetv.net
Not necessarily true, there's time where trends cause scientists to ignore past work in favour of some new fad only to go back and realize past assumptions and research were more relevant and accurate.
This comment breached our terms of use and has been removed.
This comment breached our terms of use and has been removed.
This comment breached our terms of use and has been removed.
This comment breached our terms of use and has been removed.
This comment breached our terms of use and has been removed.
This comment breached our terms of use and has been removed.
Antimatter drives are at least as possible as some of the suggestions above - more so than some. There's no impossible physics, although there is a slight problem creating enough of the stuff to be worthwhile, and a teensy containment problem (unless you can generate strange quarks and anti-strange-quarks, or something equally exotic, in which case it's possible normal matter could contain it quite happily).
It seems that using the antimatter drives is to be the most plausible way to create interstellar ships, but if you carefully read excerpts from NASA that Polemos posted here, you could find an approximate quantity of the antimatter for let's say, 10 years journey at the speed s of 0.2c and 0.7c. If you download the whole NASA abstract (about 410 pages) you could also find way of shielding, amount and types of material and techniques for shielding and increasing in weight for it, so for journey to nearest stars and back, we would need a huge amount of antimatter.
You should also consider our current possibility to produce antimatter:
"The biggest limiting factor in the production of antimatter is the availability of antiprotons. Recent data released by CERN states that when fully operational their facilities are capable of producing 107 antiprotons per second.[citation needed] Assuming an optimal conversion of antiprotons to antihydrogen, it would take two billion years to produce 1 gram or 1 mole of antihydrogen (approximately 6.02×1023 atoms of antihydrogen)." (Wikipedia)
So for 1gram of antimatter, currently we need 1 billion years of production? What to say about several thousand of tons of antimatter? Antimatter could be a solution, perhaps for solar system journey but for interstellar....? I wouldn't bet on it.
In one of NASA abstracts, to prevent ablation of the front of the space ship on interstellar journey, we should need a wall of Tungsten 10m thick 100x100m area which would weight about 100.000 tons? How to accelerate, and decelerate such a ship?
No, carrying fuel on the interstellar journey is not an option at all. Well... maybe...bring Tesla works back on the drawing table, and not only Tesla ideas, but some recent works, about energy of the vacuum and the possibilities to convert / extract use energy of the free quantum vacuum and use it to drive interstellar ships. I know, it is a long way in the future to even find if it is theoretically possible or not, but in my opinion it could be the only plausible source of energy for the interstellar trips. Of course, ablation due to the interstellar medium, shielding against cosmic radiation, and other technical problems should be also for a long time on the drawing table.
Obviously the assumption is that we would need to scale up production a lot! Nevertheless, at least antimatter is a physically possible technology, and possibly no less feasible than a Bussard ramjet (the magnetic fields required are huge unless you're in a region where the interstellar hydrogen has been ionised by some nearby object) while Alcubierre and wormholes are far more unknown quantities. So I don't think it's unreasonable to suggest that antimatter could have been included amongst the "top ten" options.
I agree with you absolutely, there is no theoretical obstacles to achieve antimatter ship's drive and this is important and plausible.
What I wanted to note is that, currently we are at least so far away with technology from antimatter/matter drive as from conversion /extraction of the free vacuum energy as the energy source. Producing antimatter even theoretically is extremely difficult and slow process, expensive as well. Even the Universe is not comfortable enough to be a big factory of antimatter, so we have such imbalance between normal matter and antimatter. Although feasible, it doesn't seem to be probable, in foreseeable future.
Although many think on the first sight that antimatter is ideal source, for a long journey on relativistic speeds above 0.2C-0.7C quantity of matter/ antimatter which should be dragged along is terribly huge.
In the deep shadows of my mind, Tesla's ideas about extracting energy from the free vacuum space is correlating with new ideas and theories about origins of matter and energy, where matter /antimatter is just a quantum vacuum with specific condensation and polarization of energies thus appearing to observer as solid matter..... even the popping up of matter antimatter particles from nothing followed by annihilation into nothing (but energy burst) supports such ideas...
Unfortunately Tesla didn't live long enough to explain and publish his dynamic theory of gravity and his ideas about vacuum energies as power sources, but having in mind what he succeeded in his life, I think that it is worth to continue on serious work on his unpublished theories.
Obviously the assumption is that we would need to scale up production a lot! Nevertheless, at least antimatter is a physically possible technology, and possibly no less feasible than a Bussard ramjet (the magnetic fields required are huge unless you're in a region where the interstellar hydrogen has been ionised by some nearby object) while Alcubierre and wormholes are far more unknown quantities. So I don't think it's unreasonable to suggest that antimatter could have been included amongst the "top ten" options.
Option #11
Mon Dec 21 10:48:06 GMT 2009 by Allan
http://www.xxxpartners.co.uk
What about the antigravity engines in the pyramids, and the captured alien technologies in Area 51?
When will we see these being made public?
Why are they being hidden?
This comment breached our terms of use and has been removed.
I'm reliably informed by someone who knows that some of these secrets will be revealed during the Christmas Day Ant & Dec special.
This comment breached our terms of use and has been removed.
What you are looking for is the last option, Heim Theory or as newer variants are called Extended Heim Theory.
The Mark McCandlish ARV (Alien Reproduction Vehicle) "Flux Liner" had a large electromagnetic solenoid coil around the circumference of the ship as well as a large flywheel just above the electromagnetic solenoid coil.
McCandlish reported this back in 2001 at the Disclosure Project.
The AIAA award winning paper on Extended Heim Theory was put out in 2004.
It is doubtful the EHT guys ripped off McCandlish because at the time McCandlish thought that the parallel plate capacitors on the bottom of the craft were what propelled the ARV (ala Biefeld Brown Effect).
So, what are the odds of a report on a U.S. made Alien Reproduction Vehicle having the same parts as EHT deems necessary for faster than light propulsion?
Sorry, I have a patent on that. The license fees are too high for even the US government...
Right idea wrong place .They dont have anti gravity .They arent even close .This is the only way to travel in space thats practicle ..With out it the human race isnt going any wheres out there .We will remain locked in our solar system and even then in a limited way for ever until they break gravity barrier. No anti gravity no star travel or any thing else to amount to anything .
All comments should respect the New Scientist House Rules. If you think a particular comment breaks these rules then please use the "Report" link in that comment to report it to us.
If you are having a technical problem posting a comment, please contact technical support.
PRINT
SEND
