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How do we include people in space settlements, the colonization of space?

Currently in microgravity, robots have an economic advantage over people and machines.  They can be designed for microgravity conditions, they require minimum re-supply.  They can be smaller and lighter than people, and can have hardened radiation tolerances.

The disadvantage of robots without people is that they don’t do a good job of repair/maintenance, and they are not flexible for multiple tasks.  People with robots or machines are very flexible, but are expensive to support in microgravity.

People can overcome the economic advantage of robots in space if they can solve the problems of re-supply and radiation more cheaply than currently in the microgravity environment of the International Space Station (ISS). The cheapest place to do that is in low earth orbit (LEO) because the costs of re-supply from Earth are the smallest.  For radiation hazards, LEO is more protected from radiation because of the Earth’s magnetic field.

Gravity (or its simulation) is important in a manned structure in LEO because it allows for much cheaper and more varied uses than can microgravity structures in LEO.  A structure in LEO with an artificial gravity by rotation would allow manned habitation to become much cheaper by eliminating resupply.  I understand the figure to support humans to be 40 lbs of air, food and water per person per day.  At the standard $5,000/lb to LEO cost, that works out to $200,000 per day per human.  With a modest presence, say 10 people in a facility,that is $2 million per day to keep the people alive and functioning.  Closed ecologies have been demonstrated and have much lower operating costs.  NASA had one that I visited a long time ago at the Air and Space Museum that had 4 people in a facility for 3 months that fully recycled air and water.  But that is in a gravity environment.  I assume that fully closed ecologies have already been demonstrated on Earth.

Human functioning efficiency in LEO would be vastly improved by being in a simulated gravity environment, even one that has only a martian simulation (as I propose).  Our standard technology processes should work more or less as we expect them to for food production and technology utilization, so we won’t have to develop new microgravity processes first.  For food production, life has evolved in a gravity environment for billions of years.  Our multiple experiences with growing food are in a gravity environment.  It is the same with our technology.  We can buy and use standard products manufactured on Earth, to grow food, and to perform desired work in LEO.  We will have to pay attention to weight for delivery costs, and also to the products ability to function in our slightly different environment, low g by rotation.  There will be many choices for off the shelf products so we can tailor our choices to the ones appropriate for each project.

Many uses for cheaply built structures, with cheap production processes, that are cheaply run by humans in closed ecologies come to mind.  The one I proposed as part of the creation of a Space Based Solar Power system (SBPS) has about 10,000 habitable square feet, half in a “martian” .4G environment, half at lower gravities including microgravity.

A way to take advantage of people’s capabilities is to more cheaply get stuff to LEO.  In rocket launches, the main booster is launched and burns up to allow the payload booster to reach LEO.  That main booster has quite a bit of altitude and speed when it separates to burn up.  You can add another main booster that burns up in order to take the original main booster into orbit and lower the cost.

I had an analysis done using the case of the Delta-IV launch configuration.  It is a set of 3 main boosters that launch the payload stage to LEO.  In the analysis I had done, I had added to the standard configuration, another set of 3 main boosters to burn up on the way.  The results of the analysis are that you double the cost of the launch, but more than triple the payload to LEO [link to my explanation of the analysis on the sps website page 2].

The standard cost of a Delta-IV launch is about $250 million and payload to LEO is 22.5 metric tons.  With the additional main boosters, the payload to LEO is over 80 metric tons.  That means that for each launch with the additional boosters, 3 boosters and additional mass are the payload to LEO.  With 12 main boosters (4 launches) a structure can be created that is 6 boosters long, with 3 boosters on each end.  This structure can be caused to rotate at 2 revolutions per minute.  I choose that rotation figure because it has been shown to be the maximum most people can tolerate easily.  That rotation across the 100 meter radius gives an artificial gravity of approximately .4 Earth gravity, like that of Mars in the 6 boosters at the ends of the string of 6 main boosters.  For the cost of 4 launches (each at twice $250 million) you can get the structural pieces to LEO for about $2 Billion.  I actually figure the cost of each of these structures to be $3 Billion including building them in LEO from the structural pieces.  Only the first of these artificial gravity structures may cost more if a new launch platform needs to be built for the non-standard launch configuration.

That is quite a lot less than the ISS costs, over $100 Billion currently.  This artificial gravity structure would also be cheaper to run with utilization of standard recycling technologies.  The living and working modules built on Earth can be placed inside the fuel tanks for each main booster, adding 2 layers of protection from the space environment.

Here are some potential uses, some may be combined together:

An SBSP project. A remanufacturing facility in LEO that takes the empty booster material stream, and mates it with solar power cells and microwave transmitter elements from Earth to create solar panels in LEO.  Those panels are then robotically sent to GEO with ion engines using the power of the solar panels, mated to ion engine fuel from Earth.  An additional materials stream for remanufacturing could be space debris. [show link to my sps1 web page]

A “Space Dock” in LEO.  A facility that can offer spacecraft repair, construction, parts manufacturing, mating, fueling and checkout.

A Low G medical facility.  There are obvious potential benefits of a low-g environment for medical issues of muscle recovery, like from a heart attack, just to name one.  Also to test for Mars medical problems.

A NASA simulation environment for the Moon and Mars to test all types of equipment for those plantetary habitats at lower cost and lower danger by virtue of being close to Earth.

A Space Hotel that offers not only microgravity and all the possibilities of outer space, but also offers a simulated martian and lunar environment.

I don’t see any cheaper and faster way to get these results than with this kind of project.

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