Space and the environtment

This is a slightly edited version of Chapter 13 of Space Exploration: All That Matters, David Ashford, Hodder and Mc Graw-Hill, 2013. It considers the environmental balance sheet of using spaceplanes to greatly increase the number of space flights per year.

The main disadvantage will be increased atmospheric pollution. Spaceplanes climbing to space will cause injections of pollutant into the high atmosphere. It is likely that the propellants will be liquid hydrogen and oxygen. The exhaust product will therefore be water vapour, which is non-toxic. It may, however, be persistent and the effects will need to be studied carefully.

The first benefit is that spaceplanes will greatly reduce the cost of environmental science from space, which is a key to understanding human impact on the environment. There will be a rapid gain in environmental knowledge, which will help us to restrict our polluting activities in a more effective manner. The large Envisat satellite, for example, was launched in 2002. It worked for ten years before being declared no longer operational. It led to much ground-breaking research in the fields of atmospheric chemistry, ozone depletion, biological oceanography, ocean temperature and colour, wind waves, hydrology (humidity, floods), agriculture and arboriculture, natural hazards, digital elevation modelling, monitoring of maritime traffic, atmospheric dispersion modelling (pollution), cartography and study of snow and ice. However, it cost about two billion dollars to develop and launch, and very few such satellites can be afforded. However, with low-cost access by spaceplane, several satellites of this kind could be built. They could be optionally man-tended and could be larger and more capable than Envisat.

First - environmental benefit

Second - environmental benefit

The second benefit is a boost to the hydrogen economy. Spaceplanes are likely to be among the early large-scale commercial users of liquid hydrogen fuel, which in turn will make it easier for it to be adopted for aeroplanes and ground transport systems.

The third benefit, which is longer-term, is that using resources from space will reduce the pressure on our own planet. Two likely candidates for first place are solar power satellites and mining asteroids.

Large satellites for collecting solar power and transmitting it to Earth have been the subject of much study. Their potential is vast indeed. The energy from the Sun reaching the Earth in just three days is equal to that in the fossil fuels needed to keep the human race supplied with energy for 100 years at the present rate of consumption. A satellite of just 250 km diameter could supply all of our present energy needs, assuming 10% overall efficiency, with a very low carbon footprint.

Not one light bulb on Earth has yet been lit using power from space. Spaceplanes will enable the construction of satellites large enough to explore the feasibility of solar power collection in space for use on Earth. It is clearly prudent to do research on such future energy options as soon as the cost permits.

Third - environmental benefit

Fourth - environmental benefit

The fourth benefit, which is perhaps longer term, is that low-cost access to space would facilitate setting up a defence against asteroid impact and developing climate modification technologies, should these become necessary.

Another benefit, less directly linked to the environment, will be new jobs and economic expansion. Space tourism in the near term and space manufacture and maybe solar power later on will create large numbers of new skilled jobs.

These disadvantage and benefits can be reliably expected. The remaining benefit is more speculative because it involves human psychology. What will be the effects on human thinking of large-scale space tourism, space art, space sport, and expanded space science and exploration? Some indication is available from the experience of astronauts. Most have said that going to space was a transforming experience, and that they would like to go again. They tend to return to Earth with a more global perspective than when they left. They are more conscious of the fragility of ‘Spaceship Earth'.

When a million and more people visit space each year, we can expect these views to spread, which should make it easier to generate global action to counter the various perils that face our home planet.

There are two historical analogies. First, Europe benefitted greatly from discovering the existence of America. The benefits were both material and cultural. The resulting challenge to traditional thinking provided a boost for the Enlightenment. Could large-scale space exploration and tourism provide a comparable benefit to the entire planet?

Second, many people consider that the main benefit from the Apollo lunar landing programme was the famous Earthrise photograph, Fig. 13.1, of the Earth appearing to rise above the Moon. To quote from a senior NASA Apollo engineer, Henry O Poh, looking back on Apollo:

“Probably the most significant benefit of the Apollo programme was pictures from space, allowing everyone see the Earth for what it was—a little ball with a very thin, fragile atmosphere around it. One picture from Apollo of the whole Earth caused the entire world to start thinking about what we were doing to the environment and the planet. That picture may have done more for mankind than any other single thing—just giving us a perspective of he world we live in. That’s something we don’t normally think about. For the first time, man could see the Earth all at one time and realize it as a very small, very fragile planet, and we were really destroying it fast.”

I well remember seeing Earthrise for the first time and, like billions of others, starting to take Greenpeace and Friends of the Earth seriously.

Figure 13.1. ‘Earthrise'. Taken from Apollo 8 by Frank Borman in December 1968. This photograph soon became the icon of the environmental movement. [NASA]