If the Earth is to be saved from the ultimate threat of destruction, it maybe by the knight-errant Don Quixote.
The threat is from impact, the Hollywood-beloved nightmare of a Near-Earth asteroid on an orbital path that will lead to a collision with the planet. It has happened before. The Earth’s surface bears witness to large meteorite strikes over the spread of geological history. The most obvious is this, the Barringer crater, and the most famous the asteroid that (perhaps, or probably) led to the Cretaceous- Tertiary extinctions.
Future potentially hazardous asteroids are measured on something called the Torino Impact Scale, which ranges from score 0 (safe) to 10, global catastrophe.
There are a lot of near-Earth objects out there. The Minor Planets Centre lists those waiting to be studied here, hoping that amateur as well as professional astronomers will study them and identify threatening orbits. A piece of hurtling rock named 2008TC3 was confirmed as heading for Earth this way. Part of it ended up hitting Sudan.
In fact, 2008TC3 posed no great threat. But how would humanity respond if a Near-Earth object did turn out to threaten catastrophic impact? One that might come very close is the asteroid 99942 Apophis, which according to current estimates will pass close to the planet in 2029 and again in 2036. Apophis weighs in at some 46 million tonnes. It might matter.
Enter Don Quixote, the name given by the European Space Agency to an ambitious two-spacecraft project that seeks to achieve two things and may well be used on Apophis in time.
One spacecraft in the pair is Sancho, an orbiter that will gather vital information about the asteroid’s composition. It matters a lot what it is made of and asteroids vary from piles of rubble loosely bound together to single pieces of rock. To get this kind of information, Sancho will need to resolve the surface of the asteroid at metre height. It will also measure the Yarkovsky Effect, that is the way the asteroid is emitting heat, because that will reveal a lot about what will happen to the asteroid after it gets hit.
The second spacecraft is Hidalgo, an impactor. Hidalgo will be called out of a parking orbit to change the asteroid’s semi-major axis – to bash it off orbit, in non-space speak. If Hidalgo strikes while the asteroid is passing through a ‘keyhole,’ a particular moment in its orbit, then a change in axis of 100 metres would be enough to render it safe.
There are other plans. A Chinese system also intends to knock asteroids off orbit. Wilder schemes include attempting to destroy a threat with a nuclear missile strike, which might make a good film but would have the unfortunate consequence of strewing near space with irradiated chunks of rock armed with completely unpredictable new orbits. At the moment, Don Quixote is the most advanced programme that the world has.
Why Don Quixote? I am fascinated by the choice of name. Will Sancho take the pictures and then the Hidalgo save us? There have been many, many reincarnations of Son Quixote since Cervantes’ time, and the knight has been re-enlisted to fight many different battles. Hugo Chavez launched Operation Dulcinea in 2005 to distribute free copies of the book around Venezuela. 'We're still oppressed by giants', the Venezuelan Minister of Culture, Francisco Sesto, told the BBC, 'so we want the Venezuelan people to get to know better Don Quixote, who we see as a symbol of the struggle for justice and the righting of wrongs.'
Culturally, the figure of the knight has meant different things, from Romantic hero to anachronistic madman. He is the spur to so many imaginings. This is Miguel de Unamuno, writing in the aftermath of Spain’s ‘Great Crisis’ of 1898:
‘Don Quixote travelled alone, alone with Sancho, alone with his solitude. Shall we not, his fond admirers, also travel alone as we forge a quixotic Spain from out of our imagination?’
Is it the quixotic nature of the project that inspired the name? I doubt it. The European Space Agency likes its satellites to carry meanings.
Don Quixote is, first of all, absolutely European, and the Agency has always liked to make and re-make the point that it and its creations are not American. But more interestingly, the whole mission might be seen as one worthy of a great knight, an act of love, as it were, with the Earth as the new Dulcinea. In an English-speaking context, it also carries echoes of Graham Greene’s re-working of the Don Quixote story to make of the knight a saintly figure, his great Monsignor Quixote. The satellites have a sacred aureole.
I think the idea of the saviour-spacecraft ties in also with the strange phenomenon of affection for the pieces of metal we send off to distant worlds. This has been visible especially in the two Mars Rovers, Opportunity and Spirit. Eight years after landing on Mars for a three-month mission, Opportunity is still roving the planet’s surface. But when Spirit fell silent, victim to an accident, there was real grief at the failure of this plucky little thing. It would be hard not to feel a certain surge of gratitude at Sancho and Hidalgo as they went about their work.
Is the threat if asteroid impact a windmill or a giant? Will the Don Quixote system turn out to be helmed in gold or wearing a barber’s bowl? Perhaps the most interesting aspect of its name is that the mission’s ambivalence is canonised – we don’t know whether the threat is there and if the response will work.
So we are left, it seems to me, in doubt, which is where Cervantes wants his readers to be. In his prologue, Cervantes advises his desocupado lector:
Although I seem like Don Quixote’s father, I am his stepfather... and you can say whatever you like about this history.
This has always been the guiding principle of a book that has meant, in its history, so many things. The space mission that bears his name will be similarly multivalent. But Don Quixote may yet ride again.