Sail Concepts

To Ride the Solar Wind

May 9, 2013

What we hope to learn from early experiments with the electric sail is whether keeping a steady electric potential on long tethers will give us enough interaction with the solar wind to make for viable propulsion. ESTCube-1, launched earlier this week, is a step in that direction. Even though it uses but a single 10-meter [...]

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Enter the Electric Sail

May 8, 2013

Some years back at the Aosta interstellar conference I had the pleasure of being on a bus making its way at night through the Italian alps with Pekka Janhunen sitting immediately in front of me. Janhunen (Finnish Meteorological Institute) is the developer of the electric sail concept soon to be tested by the ESTCube-1 satellite, [...]

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An Early Nod to Beamed Propulsion

December 17, 2012

It’s always interesting how different strands of research can come together at unexpected moments. The last couple of posts on Centauri Dreams have involved new work on Titan, and early references in science fiction to Saturn’s big moon. The science fiction treatments show the appeal of a distant object with an atmosphere, with writers speculating [...]

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Medusa: Nuclear Pulse Propulsion and the Sail

July 20, 2012

Hybrid propulsion technologies have emerged naturally as we look at ways to reach the stars. They’re the result of trying to extract maximum performance from each option, and it sometimes turns out that putting two ideas together works better than either by itself. Next week we’ll be looking at one such concept, A. A. Jackson’s [...]

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Science, Fiction and the Sail

June 8, 2012

Thinking about the poem “To Sail Beyond the Sun: A Luminous Collage,” which I published excerpts from yesterday, I was reminded that if Ray Bradbury didn’t spend a lot of time on solar sails, many of his compatriots did. Indeed, the early story of the solar sail is inseparable from science fiction. Astounding Science Fiction’s [...]

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Big Sails, Challenging Dreams

June 6, 2012

I’ve been thinking about solar sails these past few days, a topic that inevitably invokes Arthur Holly Compton, who first demonstrated that x-rays have particle-like properties. Compton’s experiments in 1923 produced a body of work for which he would receive the Nobel Prize in Physics later that decade. Thanks to him we learned that while [...]

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Lightsails: Safe Passage After All?

April 16, 2012

Despite my best intentions, I still haven’t put my hands on the exchange between Robert Forward and Ian Crawford on lightsails that ran back in 1986 in JBIS, nor have I managed to come up with the source of the ‘lightsail on arrival’ illustration I mentioned last week. This was the one showing a battered [...]

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Starships: The Problem of Arrival

March 16, 2012

You wouldn’t think that slowing down a starship would be the subject of a totally engrossing novel, but that’s the plot device in Poul Anderson’s Tau Zero (1970, though based on a 1967 short story called “To Outlive Eternity”). Anderson’s ramscoop starship, the Leonora Christine, can’t slow down because of damage suffered in mid-cruise. Edging [...]

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A Path Forward for Beamed Sails

December 13, 2011

Minimizing the cost of a project is no small matter because, as Jim Benford points out in the paper we’ve been examining over the past several days, cost determines how we decide on competing claims for resources. In the case of a beamed sail mission and its infrastructure, the cost is largely the reusable launcher [...]

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The Case for Beamed Sails

December 9, 2011

There is a natural path through solar sails, which are now flying, toward beam-driven propulsion, and it’s a path Jim Benford has been exploring for the last eighteen years. In my Centauri Dreams book I described how Jim and brother Gregory ran experiments demonstrating that carbon sails could be driven by microwave beams back in [...]

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