Earlier it was demonstrated that a sizeable mass of iron (approximately 10m thick plating) would be necessary as an outer radiation shield for an interstellar generation ship if simple mass shielding is the only method of radiation protection used. Since galactic cosmic rays are primarily charged particles (our test case is a high velocity proton) they are subject to a force when acted on by an electromagnetic field. It should be possible, then, to use that field to redirect particles away from the ship, in turn reducing the necessary plating mass.
Showing posts with label Starseed. Show all posts
Showing posts with label Starseed. Show all posts
October 7, 2012
Generation Starship Material Selection
The space environment is, contrary to popular belief, not that empty. It is full of various forms of radiation, many of them quite dangerous. To keep a crew happy and healthy for generations this necessitates a thick outer hull composed of the right material. Since the Starseed proposal also requires in-situ (or on-site) construction of new vehicles at their destination the material in question must also be one commonly found in, or easily fabricated from, rocky bodies in deep space. Further we will desire the material to be the lightest possible choice that can fulfill these prerequisites. Keeping the structure mass down will reduce the fuel requirements to complete the mission.
To begin with we'll need an understanding of the forms of radiation encountered in deep space. Together with understanding of how radiation shielding works this will give us an idea how thick the hull must be. Then we can consider the materials that might be available for use. Finally by calculating the thickness needed, and from that the areal density of the hull, for each material we'll know which of our options will be the lightest. This option, then, is the one used going forward.
To begin with we'll need an understanding of the forms of radiation encountered in deep space. Together with understanding of how radiation shielding works this will give us an idea how thick the hull must be. Then we can consider the materials that might be available for use. Finally by calculating the thickness needed, and from that the areal density of the hull, for each material we'll know which of our options will be the lightest. This option, then, is the one used going forward.
September 21, 2012
Hazards of Interstellar Travel
Before we can proceed in designing an interstellar vessel we must understand the environment though which it travels. The space between stars is occupied by what is called the interstellar medium, a diffuse collection of gas and dust. Dust particles are, outside of comparatively dense regions, rare in the ISM. Most interstellar matter is atomic or ionized nuclei. In space the greatest danger to crew health is from radiation. In the solar system the largest source of radiation is from the sun itself, both from high energy electromagnetic radiation and from accelerated particles moving through the sun's magnetic field. Beyond the solar system these effects are no longer appreciable and the danger comes from extremely fast particles accelerated by much larger or denser galactic bodies than our sun.
July 22, 2012
On the Requirements of a Generational Starship
In my first post relating to the idea of a multi-generational starship I outlined a mission plan. Now we move beyond that initial plan to consider some of the mission requirements. First and foremost must be consideration of the needs relating to long-term human habitation in deep space. This problem has been investigated in the past. Much of what follows is based on work done in the 1977 Princeton space colony survey: "Space Settlements: A Design Study."
The core difference in what follows is the population size. The minimum population needed for a fully self sufficient colony able to support broad based manufacturing is approximately 500,000, with at least 200,000 to provide minimum commercial and agricultural services for a self-sufficient colony. These numbers are discussed in the Princeton survey, however the colony size suggested there is a mere 10,000 individuals. This earth orbiting colony acts as an in-situ construction platform for satellites and space vehicles. Such a colony would be a necessary fore-runner to an interstellar generation ship, both as a construction facility and as an engineering and social test bed.
What follows is a more detailed analysis of those facilities necessary for a full sized generation ship. Using this further size requirements on the final vehicle are developed.
The core difference in what follows is the population size. The minimum population needed for a fully self sufficient colony able to support broad based manufacturing is approximately 500,000, with at least 200,000 to provide minimum commercial and agricultural services for a self-sufficient colony. These numbers are discussed in the Princeton survey, however the colony size suggested there is a mere 10,000 individuals. This earth orbiting colony acts as an in-situ construction platform for satellites and space vehicles. Such a colony would be a necessary fore-runner to an interstellar generation ship, both as a construction facility and as an engineering and social test bed.
What follows is a more detailed analysis of those facilities necessary for a full sized generation ship. Using this further size requirements on the final vehicle are developed.
May 18, 2012
Project Starseed
My father is a science fiction author, I highly recommend his work. He asked me, the other week, what would be necessary to actually build and run a generational starship. As we discussed some of the requirements, a design and mission profile began to emerge. This is far from complete, by any stretch of the imagination, but an idea formed. In the future it will be developed further, for now a brief outline:
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