Another way to travel to Alpha Centauri

[vgorelik]

I don’t think that carrying both - propellant and energy source is a realistic proposition for any interstellar travel. Here is an idea that occur to me while reading “Infrastructure for a robotic mission to Alpha Centauri†post on this forum:<br /><br />- Interstellar space is filled with H (90%) and He (10%.)<br />- There is approximately 10^6 gas/ion particles per m^3 of space or 9E+5 of H atoms/ions per m^3 of space between Sun and Centaury system.<br />- H is a fusible material.<br /><br />The ship would have a large diameter funnel-shaped intake manifold with magnetic coils preventing ionized particles from impacting its walls. Hydrogen ions (protons) are funneled deep down into the manifold causing its concentration and thus pressure to increase. It is unrealistic to assume, however, that pressure and gas temperature will rise to a point of spontaneously igniting the fusion. Therefore, an igniter (similar to Lawrence Livermore NIF laser array) triggers the fusion producing energy and propelling He through the exhaust manifold producing thrust.<br /><br />Btw, here is what I am building at home on my spare time and budget: <br />http://www.createthefuturecontest.com/pages/view/entriesdetail.html?entryID=74 <br />www.neuronix.net/neuronix <br />

 

[rubicondsrv]

that would be a bussard ramjet <br /> <div class="Discussion_UserSignature"> </div>

 

[vgorelik]

Hmmm... looks like I should have done my homework better...<br />But in any case - Bussard ramjet is a much better option for interstellar travel then ion propulsion discussed elsewere on this forum.<br />Couple additional notes though: <br />- free electrons must also be collected to neutralize the exhaust while these high-energy electrons could be used as additional source of energy.<br />- laser ignition will significantly reduce the min. speed requirement

 

[henryhallam]

I think it's been proven that a Bussard ramjet can't work because at a speed high enough to supply the necessary deuterium flux, the drag would be too strong. It's a very elegant idea though.

 

[vgorelik]

It would be nice if deuterium was present in interstellar environment in a significant quantity. As far as drag vs. thrust - a simple requirement is that the amount of energy produced during H fusion should exceed the loss of kinetic energy as the result of H impact. The balance will be positive up until certain speed.

 

[vgorelik]

crazyeddie:<br /><br />The engine will collect several micrograms of hydrogen per second under the following conditions:<br />- 30 km/sec (very low speed - will be much higher midway),<br />- Several miles (not hundreds or thousands miles) diameter funnel and<br />- Interstellar H density ~10E+6 particles per cubic meter.<br /><br />Yes, H must be ionized requiring ~14eV, which can be achieved by installing a relatively low power multi-THz emitters (wavelength will be shortened due to Doppler effect) in front of the engine ionizing incoming H atoms.<br /><br />