Bussard Ramjet

Description: This is named after the man who invented it, Robert Bussard in 1960. It works with the aim of negating the need to carry on-board fuel and therefore circumvent the mass ratio problem caused by the ideal rocket equation. It uses inertial confinement fusion energy but instead of carrying its own fuel it uses a giant magnetic scoop to funnel in interstellar Hydrogen (protons) which can then be fused inside the vehicle. The problem is that Hydrogen has a very small cross section and the Sun is only able to use this reaction because it has millions of years to do so within its huge gravity well. The actual spacecraft is only about 100 tons in mass but its magnetic scoop has a size of something like 10,000 km. There are problems with getting the interstellar ramject to work such as moderateing the high energy interstellar protons and mitigating the inherrent drag that the spacecraft causes as it moves through space. Variations have been proposed such as the Ram Augmented Interstellar Ramjet by Alan Bond. It is often said that the interstellar ramjet is the “great white hope” of the interstellar community and who knows time may yet yield some solutions. In theory, if it can be made to work it can go up to relativistic speeds, such as to 99.9% of light speed. At this speed the center of the Milky Way galaxy could be reached in a matter of decades, although the time dilation effects of Einstein’s special relativity theory mean that several millions of years would have passed back home on Earth.

Members: Robert Bussard.

Key References:

  • Whitmore, D, Relatistic Spaceflight and the Catalytic Nuclear Ramjet, Acta Astronautica, 2, pp.497-509, 1975.
  • Bond, A. An Analysis of the Potential Performance of the Ram Augmented Interstellar Rocket, JBIS, 27, pp.674-685, 197.
  • Martin, A.R, Magnetic Intake Limitations on Interstellar Ramjets, Astronautica Acta, 18, pp.1-10, 1973.4.
  • Bussard, R.W, Galactic Matter & Interstellar Flight, Astronautica Acta, 6, pp.170-194, Fasc.4,1960.

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