Human Spaceflight Directions, Part 4: Saving the Earth

“The earth is what we all have in common.”
–Wendell Barry

In Parts 1 through 3, I covered Nationalism, Commerce, and Science as value propositions for human spaceflight, and pointed out the challenges for each that must be addressed to make each an enduring VP.  Today I continue the examination on value propositions for human spaceflight in Part 4: Saving the Earth.


Reason 4: Saving the Earth.  In our quest to understand our universe, we often ask, “Are we alone?”  Besides the philosophical aspects of that question, the drive to understand has certainly influenced space exploration, with deep interest in the search for life elsewhere.  Whether it is sending probes to Mars to understand current and past conditions that might have been conducive to life, the discovery of water ice on the moon and Mars broadening our perceptions about the availability of water elsewhere, and the discovery of extra-solar planets over the last two decades (500 and counting) confirming that other planetary systems exist, we are seeking to understand answers to this question.

Yet in that quest we’ve had the opportunity to “turn the mirror on ourselves” and see the Earth for what it is: the lone speck in the universe (so far) that passes the Goldilock’s test: it’s just right for us.  One of the most iconic images of the space era is that of “Earthrise” over the lunar horizon during the Apollo 8 mission.  It shows the beautiful Earth, full of vibrance and color, framed by the velvety blackness of space and the harsh bleakness of the moon.  That image, and others like it, has been credited with giving rise to Earth Day and the subsequent green movement.

The fact that images from human spaceflight could give rise to whole movements begs the question: could saving the Earth become a value proposition for human spaceflight?

That begs the obvious question: how might human spaceflight play a role in saving the Earth?  Despite the images of Armageddon and asteroid deflection I may have invoked in your mind with the previous sentence, I will focus on a sole topic: energy.

Depending on whom you believe, an energy system based on fossil fuels faces two impending catastrophes: we will run out (“Peak oil is behind us, oh no!”), or the burning of those fuels will give rise to increasing concentrations of carbon dioxide in the atmosphere, leading to anthropomorphic global warming and a runaway greenhouse effect like on Venus.  Neither of those – running out of fossil fuels or a runaway greenhouse effect – is very attractive, needless to say.  Some push to break our dependence on fossil fuels with alternative sources, such as solar.  To date, solar power has relied upon ground-based efforts and improvements in solar technology to bring this capability to market.  Yet even with those improvements, solar is not competitive yet with fossil fuels on a kilowatt-hour per dollar basis, even with oil hovering around $100 per barrel.

Recognizing that solar power as implemented today is not cost competitive with fossil fuels on a cost basis, some have promoted an alternative:  space-based solar power.  Space-based solar power takes advantage of higher collection rates, longer collection periods, and elimination of atmospheric and weather interference.  Huge solar collection facilities in Earth orbit could collect the sun’s rays and beam the energy to Earth in the form of microwaves.  Microwave-receiving stations could be built into the existing electricity network and break our reliance on burning fossil fuels for electricity generation.  Through today’s technologies, human spaceflight could become the means of assembling and maintaining the space-based infrastructure for space-based solar power.

Solar power has a surprisingly long history relative to the space era.  In the world of fiction, space-based solar power dates back to the 1940s.  In the 1970s during the Arab oil embargo days, the Department of Energy and NASA cooperated on studies concerning space-based solar power.  Work is still ongoing today, in part by government space agencies and in part by research centers and enthusiasts.  Additionally, NASA has demonstrated the capability to assemble large structures in low Earth orbit – see the International Space Station.  Imagine engaging human spaceflight on a grand project to build huge solar collectors on orbit and perform maintenance and operations once deployed.  All of the pieces appear to be there, or tantalizingly close.  What would it take to bring space-based solar power to fruition?

One of the challenges in grappling with the Saving the Earth value proposition revolves around the doomsday scenario of peak oil I illustrated above.  No one can question that if we run out of fossil fuels, the results would be catastrophic.  The problem is this: in what timeframe might this occur?  What trades can we make concerning investment now in space-based solar power versus addressing the uncertainty of whether or not peak oil is behind us?

A second challenge is in the efficiency arena.  Converting sunlight into microwaves in earth orbit, transmitting those microwaves to the ground, and converting the microwaves into electricity at ground stations suffers from efficiency losses of about 50%, or roughly on par with fossil fuel efficiency.  Does the private sector see enough of an upside in the approach to invest in improving the efficiency of space-based solar power in the near term, versus making those investments in further technological improvements in ground-based solar power or other green technologies, such as biofuels?

The last challenge is in launch costs.  Using a solely private approach, what is the tipping point for cost per pound that makes space-based solar power attractive?  What if Government subsidized launches – how would that change the equation?

There are a lot of questions in my mind concerning space-based solar power.  Thankfully, there is an active community, such as my friend Eva-Jane Lark, engaged on this topic.  Suppose that this community finds solutions to the lingering efficiency, financing and launch cost challenges.  Is supporting space-based solar power as a “saving-the-Earth” value proposition an enduring one for human spaceflight?

Next time: Part 5.

Text © 2011, Joe Williams.  All rights reserved.
Photo credit: NASA

Human Spaceflight Directions, Part 4: Saving the Earth