Sunday, 15 November 2015

The Case for Space Solar Power

By John C. Mankins

Book review by Adam Manning

Space Solar Power (SSP) has always seemed a tantalisingly attractive concept; harnessing some of the enormous and endless power of the Sun that comes our way and putting it to work here at home.  The basic structure consists of large solar power stations in space that receive energy directly from the sun’s rays. This energy is then converted into a form that can be transmitted through the Earth’s atmosphere to receiving stations on the ground and then distributed for use across the power grid.  If implemented, SSP could have enormous implications for energy use, for technology and for our geo-political relationships that are driven by the powerful influence of our petroleum based economy.

The Case for Space Solar Power is a timely update on SSP with a detailed review of its origin and development, a new proposal for possible implementation and a look at its overall feasibility.  The author had a long career with NASA, including ten years as the manager of its Advanced Concept Studies, and is recognised as a leading figure in SSP.

John C. Mankins

In the 1970s SSP became linked closely with large scale plans for space settlement put forward by Dr Gerard O’Neill and one of the themes of this book is that this wasn't, in retrospect, helpful to the development of SSP research.  The initial conceptions of SSP were very large scale projects, with references to stations, usually positioned in geostationary orbit, several miles in diameter and involving hundreds of launches to establish the necessary hardware in space.

When plans of this scale were produced in the late 1970s, their enormity made them an immediate target for rejection and even ridicule.  In his book, Mankins puts this forward as one of the reasons why SSP has never been taken as seriously as it should be, despite its obvious logical attractiveness. This history of almost scorn has perhaps held back research on the technical issues that need examining if a practical project is to be implemented.

The Case for Space Solar Power puts forward a detailed account of a new proposal for SSP – the SPS – ALPHA.  A beautiful design, it takes older suggestions and updates them for the 21st century. Using a high degree of modularity and the latest in robotics, it is still a very large scale project but the use of modern engineering techniques reduces the eye watering costs of earlier proposals.  It is the discussion of the costs involved that takes us to the heart of the SSP issue.  It is widely accepted that SSP does not involve any major technological breakthroughs in the same way that fusion power does.  Yet the argument has always centred on whether, given the enormous costs of the full implementing SSP, would it be worth it.  Would the huge expenditure involved ever be paid for by the sale of the energy SSP would produce?

Mankins admirably takes into account not just the SSP system itself but also analyses the costs of the huge number of launches that such a system would require. Launch capacity is an important issue for SSP and The Case for Space Solar Power considers future reusable launch vehicles and the role they would play in transferring the SPS – ALPHA system to GEO.

I’m not going to reveal the author’s overall conclusions – please read the book for that! The book reinforced my view that more basic research into wireless power transmission needs to be carried out as this will help make the answers to these issues clearer and The Case for Space Solar Power does provide details of recent studies on this, especially those carried out in Japan.

In the original plans from the 1970s, SSP and the huge space habitats proposed by Dr O’Neill formed an almost parasitical relationship with each other – the one justifying the existence of the other.  The more modern view set out in The Case for Space Solar Power suggests this is no longer valid and SSP can be independent of any large scale space settlement, although it is likely that a much more substantial orbital infrastructure will have to arise as a result of the construction of a project the size of SPS - ALPHA.  If proponents of O’Neillian scale space habitats are justifying them with the benefits of SSP, Mankins’ book does not provide a clear foundation for that justification. Nevertheless, Mankins’ vision is of a much greater extension of human activity into space, with SSP playing an important role.

A particularly useful element of the book is a consideration of how SSP might fit with other means of energy production, especially fitting with renewable energy and the markets that might have a use for it. This more practical approach is to be welcomed after the long period of only viewing it in global energy terms.

On a more global scale though Mankins notes how SSP could play an important role in a system of energy production that seeks to mitigate global climate change. If SSP could fulfil this function, there is an urgent need to investigate it in more detail with a view to its practical implementation.

This readable and well set out book is to be greatly welcomed as an update of the concept and is highly recommended to anyone with an interest in the subject.

You can find it on Amazon (in both hardback and kindle) here: 

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