Multi-Generation Space Ships

the motivations, technology, and prospects for interstellar flight, while the balance deals with anthropological, genetic, and linguistic issues in crew composition for a notional mission with a crew of 200 with a flight time of 2 centuries.

2007-06-15: On the infeasibility of interstellar travel

We require the equivalent energy output to 400 megatons of nuclear armageddon in order to move a capsule of the gross weight of a fully loaded Volvo V70 automobile to Proxima Centauri in less than a human lifetime. That’s the same as the yield of the entire US Minuteman III ICBM force. Our entire planetary economy runs on 4TW. So it would take our total planetary electricity production for a period of 5 days to supply the necessary va-va-voom.

2009-02-01: Tau Zero Foundation

The Tau Zero Foundation is a volunteer group of scientists, engineers, entrepreneurs, and writers who have agreed to work together toward practical interstellar flight and to use this quest to teach you about science, technology, and our place in the universe.

2010-05-07: Project Icarus

To design a credible interstellar probe that is a concept design for a potential mission in the coming centuries.

2011-01-06: No Interstellar Travel Before 2200. About 10^18 Joules required, more than a Kardashev type I civilization.
2011-05-20: Star Children. It might make sense to start a religion to ensure long term space travelers retain their goals.

We are seeking ideas for an organization, business model and approach appropriate for a self-sustaining investment vehicle. The respondent must focus on flexible yet robust mechanisms by which an endowment can be created and sustained, wholly devoid of government subsidy or control, and by which worthwhile undertakings—in the sciences, engineering, humanities, or the arts—may be awarded in pursuit of the vision of interstellar flight

2013-04-25: Starship Century

Is this the century we begin to build starships?

yes

2014-03-12: Starship Century

Starship Century is a symposium coordinated by the new Arthur C. Clarke Center for Human Imagination in collaboration with Gregory and James Benford, presenting ideas from their anthology of science and science fiction. First 8 minutes most of them agree the era of interstellar starships will be 100-300 years away after there is lot of solar system development.

2015-10-21: Black hole drive

The petawatt Hawking radiation of γ-ray laser-created subatomic black holes (Schwarzschild Kugelblitzes or SKs) has been proposed as a propulsive and power source for interstellar starships. Production of a black hole requires concentration of mass or energy within the corresponding Schwarzschild radius. In familiar 3D gravity, the minimum such energy is 10^19 GeV, which would have to be condensed into a region of approximate size 10^-33 cm. This is far beyond the limits of any current technology; the Large hadron collider (LHC) has a design energy of 14 TeV. This is also beyond the range of known collisions of cosmic rays with Earth’s atmosphere, which reach center of mass energies in the range of 100s of TeV. It is estimated that to collide 2 particles to within a distance of a Planck length with currently achievable magnetic field strengths would require a ring accelerator ~1k light years in diameter to keep the particles on track.

2016-02-20: Interstellar Propulsion. A 100kg robotic craft could be sent to Mars in 3 days with the power levels that large rockets produce (50-100 GW)

2016-04-12: Starshot. This makes me proud of our civilization: We do stuff like this.

Milner wants his $100M to fund research that will culminate in a prototype of a probe that can beam images back to Earth. The images would arrive less than 5 years after the probe reached the star.

There are no official specs yet, but the probe would have a 2-megapixel camera, along with star-finders to help it get its bearings, after it boots up on the approach to Proxima Centauri. The probe will target one of the system’s 2 sunlike stars. It will be aimed at a planet (or planets) in the star’s habitable zone, the temperate region where oceans don’t boil or freeze, but instead flow, nurturing the kind of complex chemistry that is thought to give rise to life.

2018-08-14: Propellantless interstellar travel

Researchers propose a new mode of transport which relies on electric-field moderated momentum exchange with the ionized particles in the interstellar medium. While the application of this mechanism faces significant challenges requiring industrial-scale exploitation of space, the technological roadblocks are minimal, and are perhaps more easily addressed than the issues presented by light sails or particle beam powered craft. This mode of space travel is particularly well suited to energy efficient space travel at velocities less than 5% of light speed, and compares exceptionally well to light sails on an energy expenditure basis. It therefore represents an extremely attractive mode of transport for slow (~multi-century long) voyages carrying heavy payloads to nearby stellar neighbors. This could be very useful in missions that would otherwise be too energy intensive to carry out, such as transporting bulk materials for a future colony around Alpha Cen A, or perhaps a generation ship.

2020-02-21: Interstellar Probe, weighing a few grams, and getting there in 20 years.
2020-09-03: Mach Effect Propulsion. Jim Woodward is investigating mach effect thrusters as part of NASA NIAC. If successful, this will get us to .xc, making humanity interstellar.
2022-08-05: Bow Shock Deceleration

Deceleration at the destination system is a huge problem for starship mission planning. A future crew, human or robotic, could deploy a solar sail to slow down, but a magsail seems better, as its effects kick in earlier on the approach. Looking at the image below, however, suggests another possibility, one using the interactions between stars and the interstellar medium to assist the slowdown. The bow shock produces 3D structures, surfaces within which one can move while shedding speed, perhaps braking via a magsail. Each star would produce its own unique deceleration environment, allowing us to brake where possible along the bow shock, the astropause (cognate to the heliopause) and the termination shock.

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