Travelling into space is one of mankind’s dreams, to infinity and beyond. But what does it cost us in terms of emissions?
- Rockets, emissions and a breath of CO₂
- Is Mars ‘green’? New technologies for sustainable travel
- Space exploration or Earth salvation? The ecological dilemma
Rockets, emissions and a breath of CO₂
Going to Mars is not exactly like taking a low-cost flight for an exotic holiday. To send a human crew to the Red Planet you need huge rockets, and these rockets have a small, negligible problem: they pollute. A lot.
A single launch of a heavy rocket like NASA’s Space Launch System (SLS) can release between 150 and 300 tonnes of CO₂ into the atmosphere, according to data from NASA and theEnvironmental Protection Agency (EPA). To put things in perspective, a long-haul flight generates about 1 tonne of CO₂, so a single space launch is equivalent to around 300 times that of a normal aeroplane flight carrying hundreds of passengers.
And it is not just CO₂ that is the problem: solid rockets also release aluminium oxides and chlorine, which damage the ozone layer. And if you thought paraffin rockets were the solution, know that they release soot and black particulates, worsening global warming. In short, each launch is like a giant cigarette smoked directly in the face of the earth’s atmosphere.
What about Mars? Well, to establish a self-sufficient colony would require hundreds of missions to transport materials, people and supplies. So yes, the dream of setting foot on the Red Planet is likely to make ours a little greyer.
Is Mars ‘green’? New technologies for sustainable travel
All is not lost. Space agencies and private companies are working on the development of cleaner technologies. For example:
- Methane rockets: compared to refined paraffin, liquid methane reduces soot production.
- Reuse of rockets: SpaceX’s Starship allows rockets to be reused several times, lowering the environmental impact per launch.
- Nuclear propulsion: NASA and DARPA are developing nuclear thermal engines, which could halve the travel time to Mars and reduce the amount of launches needed for a mission. Fewer launches = fewer emissions.
- Green fuels: some scientists are experimenting with propellants that are less toxic and have less impact on the atmosphere.
The space industry has realised that if we want to terraform Mars, perhaps we should first avoid ‘deterraforming’ the Earth.
Space exploration or Earth salvation? The ecological dilemma
And here comes the dilemma: does it make sense to invest billions to colonise Mars while our planet is facing an unprecedented climate crisis? Some argue that we should focus resources on combating climate change before thinking about escaping to an inhospitable desert planet.
On the other hand, space exploration has always brought useful innovations to Earth: from solar panels to energy efficiency, from water desalination to super-strong materials. Perhaps the key is to harness the race to Mars to develop technologies that will also help our planet survive.
What is certain is that Mars is not our ‘Plan B’. It won’t be for decades, if not centuries. And in the meantime, it would be a shame to reduce the Earth to a giant polluted launch pad. So, let us explore space… but let us not forget to take care of the planet that gave us the chance to dream of the stars.
Play for the planet!