Introduction

The subject of human space exploration has historically been controversial in the UK, with many scientists believing that the resources would be better invested in robotic space missions. However, in recent years UK policy has shifted considerably in support of human space exploration, and in July 2015 the UK Space Agency published its National Strategy for Space Environments and Human Spaceflight which has as its stated goal that:

The recent flight of the UK's first European Space Agency (ESA) astronaut, Major Tim Peake, and his Principia Mission in December 2015 epitomises the extent to which UK space policy has moved to embrace human space exploration.

This shift in policy has occurred in the context of developments in international space policy over the past decade. In May 2007, 14 of the World's space agencies published the Global Exploration Strategy: Framework for Coordination which provides a global vision for future space exploration, focussing on planetary destinations where humans may one day live and work. The Global Exploration Stretegy (GES) resulted in the creation of the inter-agency International Space Exploration Coordination Group (ISECG) to coordinate global space exploration activities. In August 2013, ISECG produced a Global Exploration Roadmap, which outlines how different national space agencies may contribute to a global space exploration programme.

In part, these developments have occurred as a result of arguments in support of human space exploration that have been developed over many years. We summarise these arguments here (further details can be found in the bibliography).

The multiple scientific and societal arguments for human space exploration

Human beings are uniquely qualified to undertake several key scientific investigations in the space environment (ranging from life and physical sciences research in microgravity, to geological and biological fieldwork on planetary surfaces). This potential has in fact been recognized by a number of recent studies. Firstly, in 2003, the independent Microgravity Review Panel examined the scientific merits of microgravity research to be conducted on the International Space Station (ISS) and concluded that the potential benefits are sufficiently great that the UK should participate in this programme. Then, in May 2004, the Cross Research Council Report identified a wide range of potential scientific benefits from participation in the human spaceflight aspects of the Aurora programme, and explicitly called for a re-examination of UK policy in this regard. This was followed in October 2005 when the Royal Astronomical Society issued it's Report of the Commission on the Scientific Case for Human Space Exploration , which drew attention to wide ranging scientific and cultural benefits of human space exploration. Meanwhile, in a European context, in 2008 the European Science Foundation issued its Report on a Science-Driven Scenario for Space Exploration, which also identified many scientific benefits of HSF and argued for continued European involvement in human space exploration in the context of the Global Exploration Strategy. The widespread economic and cultural benefits of space exploration are outlined in a White Paper on Benefits Stemming from Space Exploration published by ISECG in 2013, and the specifically scientific benefits were addressed in a 2017 White Paper on Scientific Opportunities Enabled by Human Exploration Beyond Low-Earth Orbit.

Research in Microgravity

The microgravity environment of low Earth orbit provides unique opportunities for research in the life sciences (including human physiology and medicine), materials science, and fundamental physics. Further progress in these areas will rely on the unique capabilities of the International Space Station. Although the UK has so far opted out of microgravity research on the ISS, the potential scientific benefits are well documented and were recognized by the Microgravity Review Panel which noted that:

Probably the most important scientific benefits of microgravity research will accrue to the life sciences where research in the space environment has demonstrated the potential to provide unique insights into such areas as gene expression, immunological function, bone physiology, and neurovestibular and cardiovascular function. These areas are important for understanding a range of terrestrial disease processes (e.g. osteoporosis, muscle atrophy, cardiac impairment, and balance and co-ordination defects), and as such have potential medical applications here on Earth. The UK has a growing space biomedicine community well-placed to benefit from, and contribute to, these important research fields. The UK government's decision in 2012 to participate in the European Space Agency's 'Life and Physical Sciences in Space' (ELIPS) programme, and to highlight microgravity research as part of its 2015 National Strategy for Space Environments and Human Spaceflight, will help UK researchers to engage in these activities and is therefore to be welcomed.

Space Astronomy

From almost the very beginning of the space age, astronomy has benefited from being able to place instruments above the obscuring effects of Earth.s atmosphere. Most of these observations have been performed by robotic spacecraft, without human intervention. However, one of the principal lessons from the most successful of these instruments, Hubble Space Telescope (HST), is that access to a human spaceflight infrastructure can greatly extend the life, and enhance the efficiency, of space-based astronomical instruments. Since its launch in 1990 the HST has been serviced by four Space Shuttle missions, and a fifth now appears likely. As documented by a recent report of the US National Research Council on the Assessment of Options for Extending the Life of the Hubble Space Telescope, without this human intervention the HST would have been a much shorter lived, and far less scientifically versatile, instrument than it has in fact turned out to be.

There are important lessons here for the future of space astronomy. A number of large space-based telescopes are currently being planned (including the James Webb Space Telescope and ESA's Darwin project, in both of which the UK has an interest), and the HST experience teaches us that the operational lifetime, and scientific productivity, of these instruments are likely to be enhanced if a human spaceflight infrastructure exists which is able to maintain and upgrade them. In the longer term, astronomy may also benefit from a renewed human presence on the Moon, as the lunar surface provides an excellent location from which to perform astronomical observations across a wide range of wavelengths (for example see the document on Astrophysics Enabled by the Return to the Moon produced by the Space Telescope Science Institute, and the summary of a Royal Astronomical Society meeting on Astronomy from the Moon in 2008).

Planetary Exploration

The Apollo programme clearly demonstrated the scientific value of astronauts as explorers of planetary surfaces, principally because they bring agility, versatility and intelligence to exploration in a way that robots cannot. Although it is true that humans will face many dangers and obstacles operating on other planets, mostly due to their physiological limitations when compared to robots, the potential scientific returns (resulting from rapid sample acquisition, the ability to integrate widely disparate data and past experience into a coherent picture, and the on-the-spot ability to recognise observations to be of importance even if they relate to phenomena not anticipated in advance) is more than sufficient to justify employing astronauts as field scientists on other planets. These scientific advantages of having human explorers on the Moon and Mars were recognized by the Royal Astronomical Society's Report of the Commission on the Scientific Case for Human Space Exploration , which concluded that:

In the specific case of lunar exploration, these arguments have recently been reiterated by the US National Research Council's report on The Scientific Context for the Exploration of the Moon which identified a number of areas where a renewed human presence on the Moon would yield scientific benefits not otherwise attainable. There is little doubt that the UK planetary science community would benefit from involvement in these exciting activities.

Science Education

Space exploration is inherently exciting, and as such is an obvious vehicle for inspiring the public in general, and young people in particular, to take an increased interest in science and engineering. This was explicitly recognized in the conclusions of the UK Microgravity Review Panel:

A similar point was made by the RAS Report, which concluded that:

Although these arguments have so far fallen on deaf political ears in the UK, such inspiration must be of value to any modern, knowledge-based economy, especially at a time when the number of young people opting for careers in science and engineering is falling.

Industry

Human spaceflight is technically very demanding, and this is indeed one of the reasons why it is so expensive. However, for this very reason, engaging in human space activities must necessarily act as a stimulus for employment, skill development, and technical innovation in the participating industries. This expansion of technical capabilities is likely to find applications in other areas of the wider economy. Moreover, under the ESA principle of juste retour, expenditure incurred as part of ESA's human spaceflight programmes would be invested back in UK, thereby stimulating UK industrial innovation and protecting UK jobs.

Furthermore, when considering the potential economic benefits of ambitious space projects, it is necessary to consider the beneficial multiplier effect on the wider economy resulting from employment in key industries. Human space exploration may be expensive, but the money itself does not leave the Earth. Rather, it stays on the ground where it can help stimulate economic activity. A detailed study of the wider economic effects of space expenditure was performed by Bezdek & Wendling (1992), who traced the influence of NASA.s 1987 procurement budget of $8.6 billion dollars on the US economy. An important result of this study was that while the initial beneficiaries of NASA procurement were the large aerospace companies, much of the economic benefits filtered down through layers of sub-contractors to the industrial heartland of America. As noted by Bezdek and Wendling in the conclusion of their study:

International Cooperation

Space exploration provides a natural focus for international cooperation, as indicated by the collaboration of some 15 nation states in the construction and operation of the ISS and the recently formulated Global Exploration Strategy. In trying to build a stable geopolitical environment on Earth, it must be desirable to increase the range and depth of such collaborative endeavours. Human space exploration is especially, and perhaps uniquely, well-suited to enhancing a sense of global solidarity owing to its globally high media profile. From this point of view, it would seem to be desirable that a major economy such as the UK is seen to be pulling its weight in the international exploration of space.

Conclusions

The United Kingdom has historically stood apart from participating in human space exploration. However, the new UK National Strategy for Space Environments and Human Spaceflight, and the selection of a UK ESA astronaut, makes it clear that this historical official position has evolved considerably in favour of human space exploration. This reversal of official policy, which has recently been documented by Richard Farrimond in his book Britain and Human Spaceflight, is greatly to be welcomed because, for the reasons given above (and reiterated in the publications listed in the bibliography), multiple scientific and societal benefits of human space exploration can be readily identified. The next logical step for the UK would be to fully endorse the European Space Agency's Exploration Strategy, which, fully consistent with the wider Global Exploration Roadmap, will lay the groundwork for the human exploration of the Moon and Mars.

Select Bibliography

In addition to giving the references cited in the text, the following bibliography also provides a selected list of articles which advance the scientific and cultural arguments in support of human space exploration:

Bezdek, R.H. and Wendling, R.M., "Sharing Out NASA's Spoils", Nature, 355, 105-106, (1992).

British National Space Centre (now UK Space Agency), Report of the UK Space Exploration Working Group, (2007).

Close, F., Dudeney, J., Pounds, K., "Report of the RAS Commission on the Scientific Case for Human Space Exploration, Royal Astronomical Society, (2005).

Cockell, C.S., "The Value of Humans in the Biological Exploration of Space", Earth, Moon and Planets, 94, 233-243, (2005).

Crawford, I.A., ``Towards an Integrated Scientific and Social Case for Human Space Exploration,'' Earth, Moon and Planets, 94, 245-266, (2005).

Crawford, I.A., ``Swords to Spaceships'', first published in the political and cultural magazine Prospect , 131, 14-15, (February, 2007).

Crawford, I.A., ``Astrobiological Benefits of Human Space Exploration'', Astrobiology, 10, 577-587, (2010).

Crawford, I.A., "Dispelling the myth of robotic efficiency: why human space exploration will tell us more about the Solar System than will robotic exploration alone", Astronomy and Geophysics, 53, 2.22-2.26, (2012).

Crawford, I.A., Anand, M., Cockell, C.S., Falcke, H., Green, D.A., Jaumann, R. and Wieczorek, M.A, ''Back to the Moon: The Scientific Rationale for Resuming Lunar Surface Exploration'', Planetary and Space Science, 74, 3-14, (2012).

European Science Foundation, Report on a Science-Driven Scenario for Space Exploration.

European Space Agency (ESA), Exploring Together: ESA Space Exploration Strategy, (2015).

Farrimond, R., Britain and Human Spaceflight, British Interplanetary Society, (2013).

Fong, K., "Human Spaceflight in the UK: The Cost of Non-Participation", Earth, Moon and Planets, 94, 169-176, (2005).

Garvin, J.B., "The Science Behind the Vision for US Space Exploration: The Value of a Human-Robotic Partnership," Earth, Moon and Planets, 94, 221-232, (2005).

Green, D.A., ''How the UK Can Lead the Terrestrial Translation of Biomedical Advances Arising from Lunar Exploration Activities'', Earth, Moon and Planets, 107, 127-146, (2010).

ISECG, Global Exploration Roadmap, (August 2013).

ISECG, Benefits Stemming from Space Exploration, (September 2013).

ISECG, Scientific Opportunities Enabled by Human Exploration Beyond Low-Earth Orbit, (December 2017).

Livio, M., Astrophysics Enabled by the Return to the Moon, summary of a workshop held at the Space Telescope Science Institute, (November 2006).

Space Studies Board, US National Research Council, "The Scientific Context for Exploration of the Moon - Final Report", (2007).

Spudis, P.D., "The case for renewed human exploration of the Moon," Earth, Moon and Planets, 87(3), 159-171, (2001).

Stern, S.A., Ex Luna Scientia , The Space Review, (3 October 2005).

UK Space Agency (UKSA) National Strategy for Space Environments and Human Spaceflight, (2015).

Wakeham, B., Sykes, R., Williams, P., Garwood, S., Recommendations of the Microgravity Review Panel, (2003).

Document prepared and maintained by:

Professor Ian Crawford (Professor of Planetary Science and Astrobiology, Birkbeck College London)