All Astronautical Evolution posts in 2014:

Future growth in space still not being taken seriously (Dec.)

The SpaceShipTwo Crash (Nov.)

To the Rt Hon Greg Clark (Oct.)

Exponential Growth for Another Thousand Years: Growing into an Interstellar Civilisation: Can It Be Done, and If So, How? (Sept.)

Down with the Fermi “Paradox”! (Aug.)

The Great Space Debate – Discussion and Vote (July)

The Great Space Debate: What Should Be the Strategic Goal for Astronautics over the Next 25 Years? (May)

A Four-Point Plan for ESA (April)

Britain’s Major Tim defends the ISS against its critics (March)

Neubrandenburg Thoughts (II): Space for Peace (Jan.)

Creating a Future with Skylon (Jan.)

New in 2015:

Short story The Marchioness

AE posts:

2017: Mars…

2016: Stragegic goal for manned spaceflight…

2015: The Pluto Controversy, Mars, SETI…

2014: Skylon, the Great Space Debate, exponential growth, the Fermi “paradox”…

2013: Manned spaceflight, sustainability, the Singularity, Voyager 1, philosophy, ET…

2012: Bulgakov vs. Clarke, starships, the Doomsday Argument…

2011: Manned spaceflight, evolution, worldships, battle for the future…

2010: Views on progress, the Great Sociology Dust-Up…

Chronological index

Subject index

General essays:

Index to essaysincluding:

Talk presented to students at the International Space University, May 2016

Basic concepts of Astronautical Evolution

Options for Growth and Sustainability

Mars on the Interstellar Roadmap (2015)

The Great Sociology Debate (2011)

Building Selenopolis (2008)


Issue 108, 1 December 2014 – 45th Apollo Anniversary Year

=============== AE ===============

Future growth in space still not being taken seriously

Stephen Ashworth, Oxford, UK

Can we build a sustainable technological civilisation – while ignoring the critical question?

This is the subject of a paper entitled “Sustainability and the astrobiological perspective: Framing human futures in a planetary context”, by Adam Frank (astrophysicist, University of Rochester) and Woodruff Sullivan (astronomer, University of Washington), now published in the journal Anthropocene (vol.5, March 2014, p.32-41). There has been some discussion over at Centauri Dreams.

Frank and Sullivan propose to apply an astrobiological perspective to the question of developing a sustainable human civilisation. This leads them to consider the Drake Equation. They acknowledge that several of the terms in that equation are completely unknown at present, notably the fraction of terrestrial planets on which life appears and the average longevity of technological civilisations. Consequently their discussion of it yields no useful result apart from the speculation that if one were to explore a large enough volume of space, then one might be able to find a statistically significant sample of civilisations comparable with our own. This may or may not be true in reality (if our own happens to be the first to have yet emerged, then it would not be true – a possibility acknowledged by Frank in a press release).

This is all a distraction from the real meat of their paper, which sketches out development trajectories for Species With Energy-Intensive Technology such as our own. It is striking that this term, used throughout the paper, is nowhere defined. However, it is claimed that the mathematical variables used in their model are “not subject to a particular choice or era of technology” (see p.36, col.1, end of 2nd para). Their claim is therefore that the same basic equations model any technological species which might occur or have once occurred anywhere in the astronomical universe, whether its primary energy source is based on firewood, or windmills, or fossil fuels, or nuclear fission, or nuclear fusion, or antimatter production in space-based solar power farms, or harnessing of a rotating black hole [1], etc.

Those development trajectories plot three variables: population, per capita energy consumption, and environmental impact on an Earth-analogue planet (figures 3, 4, 5a). The assumption that the entire population remains confined to the surfaces of Earth-like planets is never stated, but everywhere apparent.

Since one of the key characteristics which distinguishes a species with energy-intensive technologies from one without is its potential access to solar system resources for settlement of space and of planets which do not have Earth-like surface environments, this assumption invalidates any general conclusions. Frank and Sullivan are only addressing the special case of a species which (for whatever reason) does not embark upon large-scale development of its local interplanetary environment.

While this is of course still a useful contribution, the unstated implication that alternatives are outside the bounds of discussion is misleading.

As Frank and Sullivan ought to be well aware, the carrying capacity of an intelligently developed planetary system is potentially orders of magnitude greater than that of any one Earth-analogue planet [2, 3].

Their misleading implication is in fact stated more or less explicitly in the same accompanying press release: “While sustainability is concerned with a particular form of life on a particular planet, astrobiology asks the bigger question: what about any form of life, on any planet, at any time? We don’t yet know how these other life forms compare to the ones we are familiar with here on Earth. But for the purposes of modeling average lifetimes, Frank explains, it doesn’t matter. ‘If they use energy to produce work, they’re generating entropy. There’s no way around that, whether their human-looking Star Trek creatures with antenna on their foreheads, or they’re nothing more than single-cell organisms with collective mega-intelligence. And that entropy will almost certainly have strong feedback effects on their planet’s habitability, as we are already beginning to see here on Earth.’ ”

Obviously, this is only true of organisms which continue to locate all their industrial infrastructure within a pre-technological biosphere on the surface of an Earth-like planet. Thus Species With Energy-Intensive Technology But Without Space Colonisation.

I contend, on the contrary, that it is precisely the issue of expanding our civilisation out into the rest of the Solar System which is most relevant for its long-term sustainability. This question needs to be emphasised, not swept under the carpet.

The response from the Minister

In similar vein, replying to my letter of 2 September, the UK Space Minister Greg Clark wrote to my local MP, amongst other things: “I look forward to representing the UK at the Council of Ministers at [the] European Space Agency in early December 2014. These remain challenging fiscal times meaning prioritisation is necessary and there is no certainty of securing further UK investments for this European Space Agency Ministerial. Please reassure your constituent that my negotiation priorities are to ensure continuation of programmes where the UK has a high scientific or commercial stake for UK companies. […] Your constituent […] may want to discuss the more specific points he raises with the technical experts [at the UK Space Agency].”

So: fine, certainly, the Minister is batting for Britain and keeping the show on the road. But he does not wish to discuss any broader strategic or political significance for space programmes.

The obvious criticism of my original letter is that it was much too long and much too unfocused. But I was feeling frustrated at the general lack of strategic vision, and just wanted to get it all down on paper. I wanted to stand up in front of the ESA Minsterial and lecture the assembled notables on what they should really be focusing on, programme by programme. Of course, in 2007 I was allowed to do more or less just that, without ESA taking a blind bit of notice!

I think that space colonisation advocates should not give up on trying to get their point across, both to our elected representatives, and to the academic and intellectual world in general.


[1] Paul Davies, The Eerie Silence (Allen Lane, 2010), p.141-143, describing an idea originated by John Wheeler, the physicist who coined the term “black hole”.

[2] John S. Lewis, Mining the Sky (Addison-Wesley, 1996).

[3] Stephen Ashworth, “The Long-Term Growth Prospects for Planetary and Space Colonies”, JBIS, vol.65 no.6 (June 2012), p.200-217.