Nerds in Space: Spinning Space Stations

Only highly trained and carefully selected astronauts go to space, with few exclusions. Yet space settlement needs economical, safe launch systems to deliver thousands, perhaps millions, of people into orbit.

If this seems impractical and idealistic, note that a hundred and fifty years ago nobody had ever flown in an airplane, but today nearly 500 million people fly each year. If we can build an economy that flies a million people into space each year, we can build an economy that attracts thousands to live in space each year.

Nerds on Earth need to become Nerds in Space because an orbiting space habitat creates an important next step in ultimately creating a sustainable habitat on Mars, making humans a multi-planet species.

The Sensational Spinning Space Station

Kalpana One is an orbital space settlement designed for 5,000 residents. Its shape is a cylinder with a radius equally about 2 1/2 football fields and a length of about 5 football fields, the longest length possible while still ensuring rotational stability.

What’s this about rotation? The radius is the minimum necessary to provide 1g of artificial gravity (approximate to Earth) when rotating at 2 revolutions per minute. And the axis of rotation is aligned with the solar system’s north-south axis to provide continuous natural light through transparent end caps.

In other words, the best of Earth without having a foot on Earth.

Orbiting Space Colonies of the Future Past

Before we go any further, some history.

Kalpana One was designed to learn from and improve upon the space colony designs of the mid-1970s that had names like the Bernal Sphere, Stanford Torus, Lewis One, and O’Neill Cylinder.

In the 1970s, it was Princeton physicist Gerard O’Neill who led two Stanford/NASA studies that supported the feasibility of kilometer-scale orbital cities. But these studies assumed that the NASA space shuttle would operate as expected, a flight every week or two that carried supplies into orbit at $500/lb, while only having one failure per 100,000 flights. Further, the studies assumed an even heavier launcher would soon follow.

As us space Nerds know, the shuttle missed its design goals by an order of magnitude and stunned the country when the Challenger exploded in 1986. When it became clear that there was no transportation system capable of supporting those 70s settlement designs, they quickly fell out of favor.

Looking back, they had some wonderful things going for them. They rotated to provide psuedo-gravity and they featured natural sunlight, even if was often through the use of mirrors.

But the earlier designs had a number of serious problems:

Those with spherical shapes required an excessive amount of radiation shielding.
The large mirrors required to bring in natural sunlight weren’t ideal.
They often suffered from rotational instability or poor wobble control.
Rotating hulls combined with non-rotating shield mass could lead to catastrophic failure modes, and the word “catastrophic” is never a word you want in research literature associated with space colonization.

A New Day for Orbiting Space Colonies

Earth’s Moon and Mars are usually considered better locations for future space colonies, mainly because us Earth Nerds are accustomed to living on the outside of a large solid sphere that conveniently provides easy access to construction materials.

But interest been renewed in an orbiting colony for substantial reasons:

1g pseudo-gravity levels are possible on orbital colonies versus the 1/3g gravity of Mars and the 1/6g of the Moon. 1g is critical for raising strong children, as fans of The Expanse know.
An orbital colony allows rapid re-suppply from Earth and communication with the Earth would be more robust.
Continuous, ample, reliable solar energy is right there.
You don’t want the 1g near the hull? Well, you’d have weightless and low-g recreation possibilities near the axis of rotation and easy 0g construction along the outside hull, although construction would largely be via robotics.
An orbital colony can service Earth’s tourist markets more easily than the Moon or Mars, and if America has taught us anything, it’s that if there is a way for a large corporation to make money off it, there is a desire to get it done.

Hull

The primary point of space colonization is to provide high quality living area for human beings. The problem is an unprotected human in high orbit (above the Van Allen Belts) can’t survive naturally occurring radiation for long periods of time, and death by radiation is not what anyone would call “high quality living.”

Not only will periodic solar events generate sufficient radiation to kill in a few hours, ubiquitous radiation of cosmic origin degrades biological tissue continuously. It also possibly turns you into the Fantastic Four maybe.

Adequate radiation protection, outside of solar flare events, can be provided by approximately ten tons of material per square meter of hull surface. Pause and let the heft of that marinade over you for a bit.

So, radiation shielding thus dominates the material requirements of an orbital space colony. And where to get all those raw materials, having learning the space shuttle won’t just fly to them to you?

The materials supply problems can be overcome, with some difficulty, by transporting materials from the Moon and Near Earth Objects (NEOs) like asteroids. No one location on the Moon will have everything required, but multiple materials sourcing could allow us to piece together the radiation shielding required, despite the substantial materials transport hurdles.

Shape

Robotics would supply the majority of the construction of the cylinder in unshielded space. The cylinder rotates in perpetuity in the frictionless vacuum of space. But wobble control is provided by weights attached to cables on motorized winches under computer control. No one wants to tumble around end over end.

The shield doesn’t rotate, always staying between the inhabitants and those pesky solar flares. The habitat does rotate and interior shielding doubles as soil for plants.

The 1g living area in the hull is supplemented by internal chambers at lower g-levels for industry, storage, agriculture, retirement communities and recreation.

Power

Solar satellites power the thing and emergency power is provided by body-mounted solar cells, which calms inhabitants nerves. We’ve seen the bad things that happen in science fiction movies.

But primary power comes from solar power satellites that beam energy to a body-mounted rectenna. Solar also powers exterior maintenance via teleoperated autonomous robots that keep systems a go, including wobble control, navigation, and rotation.

Honestly, what could go wrong?

I didn’t even go into tailored force fielding, so if that interests you, click through to the source material below. Be sure to read the rest of our series as well. We’re putting a Nerd on Mars, guaranteed.

Sources

National Space Society: Kalpana One: A New Orbital Space Colony Design
Aerospace Research Central: Architecture for a Radiation Shielded, Orbiting Habitat in the Earth-Moon System
Research Gate: Tailored Force Fields for Space-Based Construction
NASA: Guidelines and Capabilities for Designing Human Missions

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