The work of Dr.Bussard in general

[Zixinus]

One often raised objection is that Dr.Bussard was often wrong, and cite ringatron and his ramjet as examples.

Now, I'd like to know how much bullshit regarding the ramjet is the Doctor's and how much is from sci-fi authors that took the idea and ran with it. For example, did Dr.Bussard truly propose the ramjet to be used for interstellar travel with relativistic velocities?

As for the ringatron, it was never built, and I recall that the reasons why it wouldn't have worked were discovered just around that time.

We should discuss just how much failures these ideas are, and another thing: idea of Dr.Bussard that do work, or ideas that stem from his work.

I recall that his NTR concept of KIWI was written before Sputnik was even launched, and that Project Rover/NERVA is based on it. There are various reasons why we won't use NTR's, the key ones being political though.

Any other examples were the Doc is right?

[JoeStrout]

One often raised objection is that Dr.Bussard was often wrong, and cite ringatron and his ramjet as examples.

Now, I'd like to know how much bullshit regarding the ramjet is the Doctor's and how much is from sci-fi authors that took the idea and ran with it. For example, did Dr.Bussard truly propose the ramjet to be used for interstellar travel with relativistic velocities?

Henry Spencer (a well-respected authority in space circles) has written on this topic (see Bussard ramjet speed limit). It turns out that it's not as ridiculous idea as most pundits would have you believe — technically challenging, to be sure, but it just might work.

[Zixinus]

Can you get the original papers on the subject?

[lambda0]

The original version of the ramjet, that was supposed to burn directly H+H was not feasible, because of the very low reaction rate, but further versions, that use the collected hydrogen mostly as a reaction mass may be more credible.
http://www.daviddarling.info/encycloped ... amjet.html

[Zixinus]

The idea of using pure H-H reaction somehow seems ridiculous to me, for starters, it takes more energy that what is given. Surely, the Doc didn't though of doing that.

[lambda0]

The idea of using pure H-H reaction somehow seems ridiculous to me, for starters, it takes more energy that what is given. Surely, the Doc didn't though of doing that.

It seems ridiculous now, but in 1955-1960 ? I think that the Lawson criterium was not so well understood at this time.

[Zixinus]

It seems ridiculous now, but in 1955-1960 ? I think that the Lawson criterium was not so well understood at this time.

The energy required to fuse deuterium nulei is measured in kilo-electronvolts. The energy required to fuse protium nuclei is measured in giga-electronvolts. Did they know that then?

[lambda0]

The Lawson criterion was published in 1957.
The Coulomb barrier is generally a few MeV high for most reactions (and fusion occurs by tunnel effect), it was already known.

[Zixinus]

Can anybody supply me with the original papers, and what the Doc originally had in mind?

[Tom Ligon]

The idea of using pure H-H reaction somehow seems ridiculous to me, for starters, it takes more energy that what is given. Surely, the Doc didn't though of doing that.

Some time in the last year or less I corresponded with Dr. Bussard regarding the interstellar ramjet. I wish I could find the reference, because he indicated that another researcher did find a possible pathway for H-H fusion involving bismuth catalysis (I hope my memory is good on that). The reaction rate is evidently several orders of magnitude higher than for straight H-H.

Muon catalyzed fusion might be another option, but muons are not presently in ready supply. That may be a GOOD thing.

There has been, however, an objection raised that the ramjet would be excessively draggy. Dr. B counters that this objection applies only if the scooped hydrogen is brought up to ship speed (putting it in tanks, for example, or held for a while in a reactor). If the reaction is more like a scramjet, with the fuel never coming up to ship speed, the drag objection is greatly reduced. But I have no idea how one does this using bismuth catalysis.

Or perhaps we will, one day, figure out a way to turn matter directly to energy. We don't presently have the technology to build the thing, and perhaps we never will, but if you want to push lightspeed, it is not nearly so much science fiction as warp drive and hyperspace.

The inquiry involves a story, which is in the October 2007 Analog.

As for the Riggatron, since is was never built due to lack of funds, how does one say it did not work?

In any event, consider Enrico Fermi's opinion. No experiment is worth doing unless it has at least a 50% chance of failure.

[MSimon]

In any event, consider Enrico Fermi's opinion. No experiment is worth doing unless it has at least a 50% chance of failure.

Polywell should be a shoo in.

Maybe not - I recently estimated the chances of success at 60%.

[TallDave]

I'm still at 1 in 3 myself.

But oh, if it works...