The Daedalus star ship, proposed in the 1970s, would propel itself forward using controlled fusion explosions Credit: Nick Stevens/starbase1.co.uk

Bad News: Interstellar Travel May Remain in Science Fiction

19 Aug , 2008 by

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Some sobering news from a recent rocket science conference: It is highly improbable that humans will ever explore beyond the Solar System. This downbeat opinion comes from the Joint Propulsion Conference in Hartford, Connecticut, where future space propulsion challenges were discussed and debated. It is widely acknowledged that any form of interstellar travel would require huge advances in technology, but it would seem that the advances required are in the realms of science fiction and are not feasible. Using current technology would take tens of thousands of years, and even advanced concepts could take hundreds. But above all else, there is the question of fuel: How could a trip to Proxima Centauri be achieved if we’d need 100 times more energy than the entire planet currently generates?

In a previous article on the Universe Today, I explored how long it would take to travel to the nearest star using the slowest mode of transportation (the ion driven 1998 Deep Space 1 mission) and the fastest mode of transportation (the solar gravitational accelerated 1976 Helios 2 mission) currently available. I also discussed the theoretical possibility of using nuclear pulse propulsion (a series of fusion bombs dropped behind an interplanetary spaceship to give thrust), much like the 1970’s Daedalus star ship concept (pictured top).

Unfortunately, the ion drive option would take a whopping 81,000 years to get to Proxima Centauri, our nearest star, and using the Sun for a gravitational assist would still take us at least 19,000 years to reach our destination. That is 2,700 to 600 generations, certainly a long-term commitment! To put these figures into perspective, 2,700 generations ago, homo sapiens had not developed the ability to communicate by speech; 600 generations ago the Neanderthals had only recently become extinct. The nuclear pulse propulsion option seems far better taking only 85 years to travel to our nearest star. Still, this is a very long trip (let’s hope they’d offer business class at least…).

Already there are huge challenges facing the notion of travelling to Proxima Centauri, but in a recent gathering of experts in the field of space propulsion, there are even more insurmountable obstacles to mankind’s spread beyond the Solar System. In response to the idea we might make the Proxima trek in a single lifetime, Paulo Lozano, an assistant professor of aeronautics and astronautics at MIT and conference deligate said, “In those cases, you are talking about a scale of engineering that you can’t even imagine.”

OK, so the speed simply isn’t there for a quick flight over 4.3 light years. But there is an even bigger problem than that. How would these interstellar spaceships be fuelled? According to Brice N. Cassenti, an associate professor with the Department of Engineering and Science at Rensselaer Polytechnic Institute, at least 100 times the total energy output of the entire world would be required for the voyage. “We just can’t extract the resources from the Earth,” Cassenti said during his conference presentation. “They just don’t exist. We would need to mine the outer planets.”

For mankind to extend its reach into the stars, we need to come up with a better plan. Even the most advanced forms of propulsion (even anti-matter engines) cannot make the gap seem any less massive. Suddenly the thought of a warp drive seems more attractive…

Original source: Wired


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Peter Brouwer
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Peter Brouwer
August 20, 2008 4:30 AM

Listen a minute, its a bit of an exaggeration to say home sapience could not communicate by speech 81,000 yrs ago. Some of our non-african ancestors were exploring the wider world. Speech is fundamental to that journey.

Tman
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Tman
August 19, 2008 11:48 PM

I wonder what scientists one hundred years ago would have said about the possibilities of landing on other planets in one hundred years.

We have discovered technologies and aspects of physics inconceivable a century ago. Isn’t it possible we’ll make discoveries regarding energy, time and space completely out of our current grasp?

We are FAR from knowing everything at this point.

quantum_flux
Member
August 20, 2008 12:20 AM

How long with antimatter?

LLDIAZ
Guest
LLDIAZ
August 20, 2008 7:25 AM

Some scientists exist in a realm all their own apart from reality. There is no doubt in my mind that if we were to overcome the trivial pursuits of wayward governments we could absolutely topple any obstacle in our way to the stars. First fix your home then worry about your neighbors…

Feenixx
Member
August 20, 2008 12:39 AM

“come up with a better plan” – that’s exactly IT. Several different plans working together, probably, and not necessarily to do with propulsion.

In the fifties, the teacher at school told us a very similar (in many ways identical) story about traveling to the moon. It took two bright ideas and a little over 20 years…

Later, at college (after the first moon landing), I wrote a paper for an examination, demonstrating clearly that sustained flights with electric planes would not be possible… and I passed that test…

Torbjorn Larsson OM
Member
Torbjorn Larsson OM
August 20, 2008 8:41 AM
Unfortunately, the ion drive option would take a whopping 81,000 years to get to Proxima Centauri, our nearest star, and using the Sun for a gravitational assist would still take us at least 19,000 years to reach our destination. That is 2,700 to 600 generations, certainly a long-term commitment! To put these figures into perspective, 2,700 generations ago, homo sapiens had not developed the ability to communicate by speech; 600 generations ago the Neanderthals had only recently become extinct. You have to be careful there to make the comparison fair, going back in time generations were shorter. Compare with other apes like chimps that become fertile at 7ish or so. I would use 20 year/generation for convenience, while… Read more »
troglodyte
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troglodyte
August 20, 2008 8:42 AM

It is too possible!
I’ve done it.

Some Random Guy
Member
Some Random Guy
August 20, 2008 1:57 AM

This article comes only 8 days after this one:

http://www.universetoday.com/2008/08/11/warp-drive-and-cloaking-devices-not-just-science-fiction-anymore/

And I’ve seen similar articles on the (future) possibility of super-luminal space travel.

Perhaps a search of arXiv might be in order…

Some Random Guy
Member
Some Random Guy
August 20, 2008 1:58 AM

Oops, make that 9 days, lol.

agmartin
Member
agmartin
August 20, 2008 2:16 AM

Non stop from one star to another may require to much energy but a gradual approach may be easier.

Start by colonizing the asteroid belt, move out from there to the Kuiper belt, then to the inner Oort cloud, followed by the outer Oort cloud.

If all stars have an Oort cloud colonists could drift from one star’s cloud to another.

No need for star drives just generational ships, fusion power, and some way of detecting a comet sized body from a very long distance. Average distance between outer Oort cloud objects should be 10-20 AU by my calculations.

damian
Member
August 20, 2008 2:46 AM
Take a Resource Rich Asteroid, Fling it towards the sun as fast as we can, Put a high degree of spin on it to create a molten core. On its retrograde orbit, as its cooling bombard it with smaller water rich asteriods. Leave it on a few orbits to cool and create a hard mantle. Move in the Mining and building equipment. Use the Heat from the Core as an energy source to create sustained SPIN and propulsion. Extract water to create ocean and atmosphere. We need water and heat, and a nice magnetic shield. Once done, slingshot to Proxima Centauri. Full of people of course, perhaps as we figure out how to live longer and living space… Read more »
Jetlack
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Jetlack
August 20, 2008 2:53 AM

Oh how ridiculous. The life-span vanity of humans never fails to amaze me, and the fact these are propulsion scientists navel gazing their own mortality is pretty frightening.

It is utter tripe that any scientists today can have the temerity to say interstellar space travel is an impossibility. This reminds me of all those supposed geniuses who were telling us about 25 years ago that our solar system was a universal fluke and there existed no other planets revolving stars.

Its almost hilarious except its coming from the scientific community which just makes it scary.

James
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James
August 20, 2008 3:07 AM
Echoing Tman’s comment, I’d say it’s preposterous to try and predict where science and technology will be in twenty years, let alone another hundred, so categorically denying the possibility of interstellar travel at this stage is premature (at least!). As for the problem of lifespan (or even just the energy requirements to keep a human or humans alive for such a long journey)–who knows what medical science will be able to do in the near or distant future? Some kind of suspended animation, or uploading of consciousnesses to a computer so they survive such a long trip is not out of the question. While it’s obvious Star Trek-like planet-hopping is out of the question for the near future,… Read more »
Molecular
Member
Molecular
August 20, 2008 4:06 AM

What’s more unlikely to happen, that we never arrive at the technological means of venturing out from the solar system, or, we never make contact with alien beings that might give us the answer to mapping our way throughout the Universe?

If neither is likely to happen, then we’ve wasted enough time already. So, let’s just move on to something else that will eventually make absolutely no sense at all in the years to come.

Maxwell
Member
Maxwell
August 20, 2008 4:09 AM
Traveling to another star is not impossible. Making the journey in our lifetime with some kind of simple warp drive system is whats unlikely. Nothing prevents us from using a brute force method combining conventional drive systems with robotics or colony systems that can survive the lengthy journey. I believe the the solution to Drakes equation is showing itself. Of the few life giving worlds that have spawned even fewer civilizations, only an infinitesimally small number of them have made the difficult and expensive decision to become space fairing. That number again being divided by the few who survive to see themselves successful. Don’t bother asking “where are the aliens?” if you can’t make a successful argument to… Read more »
Andy
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Andy
August 20, 2008 4:12 AM
Most people seem to think that Proxima Centauri is the logical first step in interstellar travel. Why? Until we are certain that there are habitable planets in the system, what would be the point? First, we need to send out probes to the dozen or so nearest stars to find out which, if any, would be a good destination. Then, the ship we construct would have to be capable of carrying several hundreds of people. Keep in mind, once they get there they’re going to have to have everything they need to function as a new society. This isn’t a camping trip! Just think of all the people you need to have doing their jobs here on Earth… Read more »
Essel
Member
Essel
August 20, 2008 4:22 AM
Very poorly researched article. “According to Brice N. Cassenti, an associate professor with the Department of Engineering and Science at Rensselaer Polytechnic Institute, at least 100 times the total energy output of the entire world would be required for the voyage” Assuming a cruising speed of c/10, the enregy required to reach that speed would be 1/2 mv^2, a payload of 10 tonnes would need an energy of 1/2 X (10,000) x (3 X 10^8/10)^2 = 4.5 X 10^18 Joules. Earth consumes more than 6 X 10^20 Joules every year. That is 1/133 rd of energy consumption p.a. Considering a total roundtrip of 85 years and two accelration and deaccelration phases. The eneregy required would be 4 X… Read more »
R2K
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R2K
August 20, 2008 7:25 AM
“at least 100 times the total energy output of the entire world would be required for the voyage. “We just can’t extract the resources from the Earth,” Cassenti said during his conference presentation. “They just don’t exist. We would need to mine the outer planets.” Wrong. The energy stores of the earth include – an ocean full of heavy water, and continents loaded with fission fuels. That is more than enough energy. We will never make it if the “experts” dont know what they are talking about. We already have several methods for getting there in several generations, but there is little reason for people to go right now. More practical would be unmanned probes that could make… Read more »
GregG
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GregG
August 20, 2008 4:32 AM

We as a society are hardly likely to fund a mission which won’t bring results until 1000 years after our death. If we did – our descendants might think better of us than they probably are going too!

Incidentally fuelling issues aside – what kind of transmitter would the spaceship need to be carrying to send a receivable signal 7 light years?

Dutch Delight
Guest
Dutch Delight
August 20, 2008 4:40 AM

If we can’t point out why interstellar flight is not possible today, we’ll never manage to overcome that obstacle tomorrow. Regardless of the silly stories that persist regarding what people thought possible years ago.

Everyone seems to forget that those people usually pointed out serious obstacles that had to be overcome, the fact that those obstacles were overcome sooner then expected does not mean that the people pointing them out were stupid or out of touch.

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