Bussard’s ramjet ideas, followed by Whitmire’s modifications, really did open up the idea of practical interstellar flight some fifty years ago, but. Zero. T. A. Heppenheimer analyzed Bussard’s original suggestion of fusing protons, but found the bremsstrahlung losses (Bremsstrahlung is. It was in that the physicist Robert W Bussard first proposed the interstellar ramjet in his seminal paper . Bussard was born in and.
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Basic principle of the Bussard ramjet. Illustration courtesy Popular Science June Artwork of a Bussard ramjet in flight. An interstellar ramjet is an ingenious extension of the ramjet concept to provide, potentially, a highly effective form of interstellar propulsion.
It was first suggested bussardd the American physicist Robert Bussard in1 and consequently is sometimes referred to as the Bussard ramjet. Set against the desirability of achieving speeds for star travel that are a significant fraction of the speed of light is the perennial problem of rocketry — having to carry, in addition to the payload, the reaction mass needed for propulsion.
Ranjet interstellar ramjet neatly avoids this problem by harvesting hydrogen for use as a propellant from the interstellar medium.
The captured hydrogen is fed to a nuclear fusion reactor which supplies the energy for a high-speed exhaust. Bussard’s ramjer design busswrd atomic hydrogen being mechanically scooped up by the spacecraft as it went along. Even assuming a knowledge of materials science far in advance of our own, it seems inconceivable that such a scoop could be constructed with a mass less than that budgeted for the entire vehicle. A 10,square-kilometers structure made of 0.
A way around this problem is to ionize the hydrogen ahead of the spacecraft using a powerful laser. The hydrogen ions — naked protons — can then be drawn in by a relatively small Bussard collector that generates a powerful magnetic field.
Since the harvesting process is electromagnetic rather than mechanical, the scoop does not have to be solid it can be a mesh nor does it have to be unrealistically large, because the field can be arranged to extend far beyond the physical structure of the scoop. One is the enormous power needed to generate the Bussard collector’s magnetic field and to operate the ionizing laser. Another problem concerns the way the ram scoop works. As the lines of the magnetic field converge at the inlet funnel, they will tend to bounce away incoming charged particles rather than draw them in.
In effect the scoop will act like a magnetic bottle, trapping material in a wide cone in front of the vehicle and preventing it from being injected as fuel.
A solution might be to pulse the magnetic field, but ramjt implementation would not be easy.
Yet another problem is that most of the collected matter will be ordinary hydrogen which is much harder to induce to fuse than either deuterium or tritium, hydrogen’s heavier isotopes. Finally, the Bussard ramjet will only work when the vehicle is moving fast ramjdt to collect interstellar mass in usable amounts.
A modified design, known as RAIR ram-augmented interstellar rocketproposed by Alan Bond intackles the fusion-reaction problem by using the scooped-up interstellar hydrogen not as fuel but simply as reaction mass. The incoming proton stream is decelerated to about 1 MeV, then allowed to bombard a target made of lithium-6 or boron Lithium-proton or boron-proton fusion is easy to induce and releases more energy than any other type of fusion reaction.
The energy produced in this way is added to the mass stream which then exits the reactor. In the exhaust nozzle, the energy created by initially braking the mass stream is added back to it. The so-called catalyzed-RAIR offers an even more efficient approach.
After the incoming mass stream has been compressed, a small amount of antimatter is added. The reaction cross-section is not only enormous compared to fusion, it happens at much lower temperatures. According to one estimate, the energy release is such that the drive reactor of a busswrd antimatter catalyzed-RAIR accelerating at 1g buszard maintaining 10 18 particles per cubic centimeter within the reactor only has to be about 3.
The down side is that large amounts of antimatter would be needed for sustained interstellar flight.
Poul Anderson explored what might happen in the case of a runaway interstellar ramjet in his excellent science fiction novel Tau Zero. In the Star Trek universe, Busssard “collectors” are attached usually at the forward end of warp nacelles to all Federation starships to collect interstellar particles. They can also be operated in reverse to expel plasma. Tamjet components of the Bussard ramjet.
Problems and solutions Bussard’s original design envisaged atomic hydrogen being mechanically scooped up by the spacecraft as it went along.
Ram-augmented interstellar rocket A modified design, known as RAIR ram-augmented interstellar rocketproposed by Alan Bond intackles the fusion-reaction problem by using the scooped-up interstellar hydrogen not as fuel but simply as reaction mass. Interstellar ramjet in science fiction Poul Anderson explored what might happen in the case of a runaway interstellar ramjet in his excellent science fiction novel Tau Zero.