I have started the LinkedIn group ‘Interstellar Travel & Gravity Modification’ (http://www.linkedin.com/groups/Interstellar-Travel-Gravity-M…g_ugrp_ovr)

It is the precursor to the Other 100 YSS. All are welcome.

Here is the link:

http://www.wired.com/science/space/news/2008/08/space_limits?currentPage=all

Summary: “There are a lot of ideas that initially you say, ‘Hey, that might work,’” Young said. “But after a little research, you quickly find that it won’t.”

Your second point is a very valid & interesting, because a 100 generation ship to sustain life indefinitely would have to be the size of a city. Forbes recently published ‘5 Horrifying Facts You Didn’t Know About the Space Shuttle’

http://www.forbes.com/sites/carolpinchefsky/2012/04/18/5-hor…e-shuttle/

that the cost of placing a mere 7 people into LEO at between $450 million and $1.2 billion. Imagine trying to put a 10,000 or 100,000 or 1,000,000 people into space with conventional technologies. Using Shuttle’s average costs, that costs would be $8,250 or $82,500 or $825,000 billion! If you remember a few years ago NASA had plans for a $5 billion spaceship that was cancelled because it was considered too ‘grandiose’. So what would launching a city be considered?

My guess is that our planet Earth does not have even 10,000 billionaires, so who is going to fund generational ships?

Regarding Charles Pellegrino, I looked him up (http://www.charlespellegrino.com/propulsion.htm) and obviously a very fascinating and brilliant physicist, but unfortunately Project Orion, Valkyrie and the most recent Vasmir don’t meet rule 2.

A second point — I have pondered the notion of “generation ships” for most of my adult life, and I see a fundamental “problem” if you like with this approach; if we can build a vessel that can sustain life indefinitely, why would you bother looking for another planet orbiting another star — you already have all you need for continued survival, and I find it hard to believe that the 100th generation on the vessel will still want to pursue the original objective.

I also find it curious that no one brings up the “Valkyrie” studies that Charles Pellegrino has bubbling away in his spare time — okay, it is a theoretical study, but he and his collaborators have gone into pretty considerable detail regarding his ideas. Of course they rely upon large scale production of anti matter, which currently does not exist, but as Dr Robert Forward pointed out many years, it only doesn’t exist because we have never devoted any resources into doing so. (I am also sure it isn’t quite that simple!)

The term “heavy lifting” tells me that these few dozen scientist are trying to conventional (chemical, ion & nuclear) propulsion on a grander scale. They are wasting their time and ours.

If you do your financial/economic calculations you will find that this would cost upwards of $238,596 billion in today’s dollars at the very least. The real question is who is going to pay for this?

Let me reword this, more horses pulling bigger buggies will not get us to China. You need to invent the sailing machine or the flying machine.

+ I had shown that Laithwaite’s experiment showed that spinning-rotating masses create ‘non-flatness’ like Woodward’s fluctuating mases create ‘non-flatness’.

+ w.r.t ‘the absence of matter does not guarantee flatness’, I showed that independently of whether matter exists or not, g=(tau)c^2 was the equation that determined acceleration present in spacetime, in flat or non-flat spacetime.

Can you see the emerging picture? How the omega versus the tensor parts provide a common ‘mechanism’ to pull together anomalies and known phenomena?

I do believe that there is a lot going for Woodward’s work if the funding could be substantially increased for many more experiments. I have presented my comments as a comparison between Woodward’s and my approaches to a gravity modification technology, as I feel that would provide more avenues for investigation:

1. “that purport to manipulate electromagnetic fields in ways intended to achieve propulsion by generating a force in one part of a system that is allegedly not cancelled by an equal and opposite force elsewhere in the system.”

Agreed. Take a look at the momentum equation h/(lambda)=mv. Is not one side momentum and the other side a wave function? We have taken this equation for granted for so long that we miss this point that Woodward was making.

2. “there is no credible evidence that localized electromagnetic fields can be directly converted into strong gravitational fields”

We haven’t figured out the technology, and that is the only reason why this statement is true.

3. “Electromagnetic fields couple to, and have as their sources, electric charge, not mass. Gravitational fields, on the other hand, have mass-energy as their source, not electric charge (and its currents) per se.”

This is contemporary physics, and I disagree. Acceleration is present when Non Inertia Ni fields are present, whether gravitational, electromagnetic or mechanical. I develop and show that this is true in my book “An Introduction to Gravity Modification, Second Edition”, and a major portion of this was published in Physics Essays, September 2011 volume (titled Gravitational Acceleration Without Mass and Noninertia Fields).

4. Woodward explains his results by way of mass fluctuations, interesting.

I never would have thought of mass fluctuations. This has a very high degree of being the correct explanation for his experiments because h/(lambda)=mv. I take a different approach, I use Ni fields to explain forces.

5. Mach’s principle. “inertial reaction forces are a consequence of the gravitational action of chiefly the most distant matter in the universe”

This is important in physics, but I have never come to terms with Mach’s principle. My work suggests that even though gravity appears to be action at a distance, all acceleration effects are local.

‘t Hooft in a 2008 paper showed (using string theory) that the absence of matter does not guarantee flatness. Woodward has taken a different step, that fluctuating mass creates ‘non-flatness’.

In my book/paper I show that separation vectors, the basis for general relativity, can be split into 2 parts, the familiar tensor portion and the source (or omega) part. If I were to fit Woodward’s work here I would say that Woodward is working on the omega part. However, all theorists, Eric Davis included work on the tensor part.

I had suggested that Laithewaite’s work was on the omega part, too.

6. “find a way to “convert” electromagnetic fields directly into gravitational/inertial fields“

Ni fields do this.

Hope this is helpful. Again let me stress that it is so important to further investigate Woodward’s experiments, because it opens up a lot of avenues, e.g. what would Woodward’s fluctuating mass imply about the Higgs (type?) boson?

Brandon, I am in neither of the two groups that you mentioned. The status quo / stone tools implies no progress. What I’m talking about is looking at current, but more importantly reasonably near-term technology that we can expect our current technology to reach within 30 or so years. As for the second category, colony ships is an example of a huge outlandish scheme and yet it appears to be the leading concept being favored by Project Hyperion. In contrast, beamed propulsion using near-term power production is a more modest approach.

The problem is that a few dozen scientists is all that we have who are doing the organized heavy lifting in terms of serious interstellar designs. Direct those experts toward non-intermediate term mission designs and they will not be working on the mission designs which are more likely to launch first. The practical result is that the first launch is delayed.

Benjamin, it seems like you may not understand what I’m talking about. Spare nighttime power production would specifically use existing electricity production infrastructure. This would involve directing electricity to that part of the grid where microwave transmitters are connected that would then beam that energy to rectennas on the Moon (telerobotic assembly). All of this uses reasonable technology. Once the infrastructure is set up, it can be used again and again without having to set it up brand new each time. So succeeding launch costs would be less expensive than the first. This beamed propulsion system could also double as a transporter for heavier payloads throughout the solar system.

I would see the interstellar missions as being completely government funded since one could not expect return-on-investment. And since it would take 30–50 years to set up the infrastructure, we would be dealing with future economic situations not the current situation. We would also be using the space technology of the time such as low-cost, reusable launchers and lunar telerobotic mining and metal manufacturing infrastructure.

However, if the interstellar experts don’t spend the time now detailing how such an intermediate plan would look like then we won’t get onto the track of promoting the steps we need to take now to be prepared to launch at the earliest possible date.

As for the the interstellar probe essentially being a rock, we launched Pioneer and Voyager craft some fourth years ago and we are still getting useful signals despite the craft not being designed to last that long.

I have no problems with diversity of ideas unless the pursuit of less probable ideas results in more probable ideas not getting the attention that a first launch mission deserves. Fundamentally, we need to identify those concepts which are more likely to be launched first and then ensure that those get enough expert development time so that the first launch isn’t delayed. That’s all that I’m saying.

John Hunt, for our discussion there are effectively two types of filters in the march to success as a society. First, is the peer review by scientist, engineers, technologies & other professionals on the feasibility of some hypothesis or project. This goes on in all forms at all organizations, and not just at conferences or in journals. That is why when private companies don’t get it right they fail, and if the failure is big enough the tax payer foots the bill.

Your low-mass-conventional-launch interstellar expedition obviously has some scientific and engineering backers.

Now the second filter and this can make or break a society. Economic feasibility. Do you really think that it is worth “terrawatts of night time spare energy production capacity” to send a tiny satellite to Alpha Centauri, to get a signal back from it 45 years later? And since it will be in the “low kilogram range” there is no guarantee that it would not be so severely damaged during its journey that it is essentially a rock by the time it gets to Alpha Centauri.

“terrawatts of night time spare energy production capacity” informs me that after spending trillions this is not going to be a repeatable process anytime soon, at least not in the way NASA’s immensely successful (at least in my opinion) Space Shuttles were.

Sure one could get government sponsorship in the US to try something like that – it was called state sponsored programs in the now defunct Soviet Union. So the second filter of economic feasibility becomes vitally important.

OK let say you managed to get government funding. I might remind you even DARPA would not go for it. DARPA found the next best solution. They started the 100 Year Starship Study.

Let us play out the scenarios. OK you got government funding, sent something off, what next? (1) More public funding? (2) Or may be angel capital? (3) Or venture capital?

Well, (3) venture capital, is out of the question because i) you don’t have a repeatable process & ii) because of (i) you don’t have a revenue stream.

(2) Angel capital is out of the question because angels at the very, very best can only do a few million.

That leaves us with (1) more public money. Do you think that is going to happen with our national debt? No.

So how are you going to progress? Note, the BRIC countries are right on our tails. Does that not worry you that these countries who have no legacy scientific interest blocks, might decide to chance it with something much more non-traditional, especially if they have done their calculations?

Now, that is why the diversity of hypotheses, theories and projects are vital to our success. It is not about “distractions”. If other types of projects are a “distraction” then conventional space interstellar travel has lost out even before it started.