Space applications are crucial to modern life…
A recent opinion piece by Jeremy Clarkson in The Sun suggests that ‘[w]e need satellites for footie and calls home… and that’s it’. The article begins with an accurate list of items that can become space debris objects, including boosters, fuel and paint, and then gives a short description of a phenomenon known as Kessler syndrome, where debris objects repeatedly collide with each other to form more and more particles travelling at orbital speed. The damage that these particles can do is also recognised: ‘one day, you’ll be watching Manchester United playing Real Madrid and the signal will suddenly die. Then your phone won’t work. Then the internet will crash. And the next thing you know, you’ll be hunting at night for your own food’. A little bit sensationalist, perhaps, but in terms of communicating how fundamental space technology is to modern life, the piece certainly gets one’s attention.
…but some think most missions a waste of time?
Unfortunately, it is then apparently suggested that these negative consequences could largely be avoided if we didn’t place non-commercial spacecraft in Earth orbit for research purposes. Space traffic control is of course a serious issue, but one spacecraft in particular is singled out as an example of the problem: one which is rather dismissed as having ‘spent the last few years watching the sea move about’. Although it isn’t mentioned by name, it is likely that the reference is to GOCE: the Gravity Field and Steady-State Ocean Circulation Explorer. But has this mission – just as an example – really been a waste of time?
GOCE has sought to measure the shape of the geoid. In common parlance we can say that water always tries to find its level, and the geoid is a way of thinking of that level writ large across the oceans. If there were no currents, winds or tides, the sea level everywhere would conform to the shape of the geoid. We would find that the sea level would rise to around 100m above a perfect ellipsoid in some places and descend below it to very roughly the same distance in others, according to local variations in gravity. In the real world, of course, with winds and tides, water is forced away from the surface of the geoid by various disturbances, and it is the force with the sea then tries to regain the geoid level that governs the direction and strength of many of the world’s ocean currents.
So, how does this help us?
Understanding ocean currents can help us to save money and lives all around the world. The El Nino phenomenon, where unusually warm water occasionally pools along the west coast of South America, seems to be associated with altered weather patterns, shifting fish stocks and – by extension – massive insurance losses. And of course, a better understanding of the baseline sea level will give us a better elevation reference system, with an improved baseline, helping us to characterise subtle movements associated with landslides, volcanism and earthquakes. If we can predict how the sea, air and earth will behave we can prepare for events, rather than react to disasters afterwards.
The benefits of observing our Earth need not be limited to disaster prevention, either. Having a better grasp of the shape of the Earth will facilitate future large-scale civil engineering projects. Understanding how ice floes will move does not simply tell us about changes to the climate, important though that is: it helps to guide ships through pack ice, shortening journeys, lowering costs, and freeing up money to do more useful things. Knowing more about soil moisture levels is allowing farmers to make better choices about their crops, which could in turn help to lower the price of food and allow us to begin turning now-excess farmland back over to nature. The list goes on and on!
However, the truth is that we very often don’t know in advance just how new information will be useful to us in the future. One of the first satellites to carry scientific instruments, 1958’s Explorer 1, was instrumental in discovering the Van Allen radiation belts, and today we use our knowledge of the associated near-Earth environment to understand how best to preserve the space infrastructure upon which we all depend. Curiosity-led research, from the microscopes that helped us overcome awful bacterial diseases to the telescopes that showed us that the Earth is not at the centre of the universe, is what drives our progress and saves human lives in new and unexpected ways.
What does the future hold?
The article then finishes by saying that these missions are ‘turning our home into a prison[, f]rom which there will never be an escape’. Perhaps this is an understandable fear, because a runaway debris problem would represent a serious threat to spaceflight, but it is also perhaps an unduly pessimistic one. Engineers are working towards debris capture missions all over the world, while scientists contribute to the development of the debris mitigation standards that increasingly define how near-Earth space can be preserved. While declaring space closed to all but football and phone calls might help prevent some debris build-up in the very short term, it would also be a much less positive development where long-term progress is concerned. If we are to continue the remarkable transformation of the past few decades, we cannot just say that the most profitable applications that have so far been found will suffice for evermore. We must instead continue to go forwards, and see what else there is to learn.