Since the end of the 30-year US space shuttle programme in 2011, manned space flight has dwindled to a series of mundane but bone-shaking bus-rides on Russian rockets up to the International Space Station in low Earth orbit. True, Nasa, still by far the world’s largest space agency, is developing a new generation of manned spacecraft. But a working prototype — let alone a new Apollo-style programme — is many years away.
Logically, this hiatus should provide an opportunity to rethink the whole purpose of sending people into space, an environment so profoundly hostile that huge sums have to be spent making travel beyond the Earth’s atmosphere even remotely safe. But too many Americans still feel a compulsion to spend billions of tax dollars on manned space flight for a re-evaluation to be politically feasible. When, in 2010, President Barack Obama scrapped the Constellation programme that would have taken the US back to the moon by the next decade, the storm of protest was intense.
The latest to capitalise on the inchoate desire to slip Earth’s “surly bonds” is the Silicon Valley entrepreneur, Elon Musk. He has come forward with a plan to revive the dream of interplanetary travel, proposing a reusable spaceship that he estimates that could travel between Earth and Mars in three months, starting sometime in the 2020s. This would be the first step to building a larger fleet and ultimately establishing colonies on other planets. In Mr Musk’s view, that could allow mankind to become a “multi-planet species” — thus cheating its inevitable extinction on Earth.
These are, of course, intoxicating visions. But they also raise questions about the merit of prioritising what remains, surely, a very long-term objective. Mr Musk’s project depends on technologies not yet in existence, whether propulsion systems or the means to protect any interplanetary craft’s human cargo against the impact of radiation in deeper space. It would require partnerships with the public sector — not least Nasa — that could cost very many billions of taxpayers’ money. Then there is the risk of failure damaging confidence in manned space flight for the longer-term future. It is worth remembering that SpaceX’s own record is not flawless. Two of its unmanned rockets recently blew up, one during a routine refuelling exercise earlier this month.
There is nothing wrong about bringing in private sector capital and know-how to back space exploration. Mr Musk’s SpaceX has, through some clever innovations, helped to bring down the cost of putting unmanned payloads into space. But manned space flight remains a grossly extravagant endeavour on any rational evaluation of the scientific benefits, which are often mentioned as its justification. If past funds had instead been invested in unmanned exploration and space science, we would know far more about our solar system, and indeed the universe, than we do today.
Apart from national pride, the real reasons for manned space flight are those outlined by Mr Musk in his presentation. Advocates talk about the benefits of international collaboration and inspiring the young. But above all, there is the human spirit of adventure, the idea that our “manifest destiny” is to move out from the Earth to explore — and ultimately to colonise — the solar system and the galaxy. This long-term vision lay behind Apollo in the 1960s and also underpins Mr Musk’s interplanetary vision. While many people will now regard it as more fantastic than inspiring, it remains the best justification for sending people into space.