Nasa has announced plans to return to the moon, for good this time. I was incredibly excited to read this plan to build a new space station in orbit around our moon! How awesomely Flash Gordon is that? So it is unfortunate that this new moon station, catchily dubbed LOP-G, is a terrible idea on almost every level. It is a story of physics, money, powerful lobbies and misplaced enthusiasm- but we’ll start with physics.
To get anywhere in the solar system, you have to accelerate. The acceleration of a rocket is fixed by its fuel reserves and its mass. This is called delta-V, given in Kilometers per Second. delta-V must be spent to escape from earth, then spent to slow down again to orbit whatever it is that you’re visiting, and if you want to come home, do the whole thing in reverse. Saturn 5, the most powerful rocket ever flown, had around 18 km/s of delta-V. You need 9.2 km/s to get into earth orbit, so fully half of the Saturn’s performance was lost just to get to orbit.
There are ways to get more delta-V after launch. Spacecraft can steal the momentum of planets to accelerate using gravity assists, but this is complicated and takes years, so is no good for humans. If you could refuel your rocket in space, you could refill your delta-V, travelling further, faster or taking more stuff! There is just one enormous problem: the fuel comes from earth too. It must be flown up at ludicrous expense ($5000/kg), making it cheaper to build a bigger, badder rocket that could get further on its own in the first place.
This idea could work if you could make the fuel in space. Hydrogen and Oxygen are both found in ice, which is found on the moon. Making rocket fuel out of this could work. However, the infrastructure to do this doesn’t exist, and is not planned as part of LOP-G. All the fuel must come from earth, defeating the point. If your spaceship decided to stop at the moon station on the way to mars, and the moon has no fuel, it has just wasted precious delta-V by slowing down to stop in lunar orbit.
It’s even a bad idea for exploring the moon itself: the orbit chosen (a Near Halo Rectilinear Orbit, for the curious) is not the most efficient one for landings, and as there is no fuel on the moon, landers will still have to be expendable. It’s not even safer than Apollo- a crew stuck on the moon is equally doomed, and it is far enough away that no “Lifeboats” could be ready if LOP-G goes down, as there are on the ISS. LOP-G cannot return to earth alone, either.
Why then, is this the plan? NASA is really, really, clever. They landed on the Moon already, with 60s technology! No superfast computers. All design done with paper and rulers. They know LOP-G in its current form is useless! They are not doing it because it is best, but because it employs the most people.
NASA projects employ 10s of 1000s of Americans, and congressmen and women vote for NASA funding to keep jobs in their states. However, they do not care if the resulting space tech is good, only that the aerospace companies in their states don’t lose work. To them, a project that never flies is perfect, a cash-cow that lasts forever. There is a catchy name for this stuff- ‘Space Pork’, projects that only exist to bring home the bacon. Indeed, the mighty SLS, the rocket supposed to build LOP-G is made almost entirely out of Space Shuttle spare parts- shuttle boosters, the same engines, even the same orange fuel tank. This is deliberate by congress- the companies that did so well building shuttles do not want to lose their work, and they have lobbied not to. SLS is $4.5 billion over budget, and four years late, minimum.
SpaceX has demonstrated almost meteoric success, and this lack of political pork really helps. SpaceX does not get money regardless of success: their jobs will not exist if good rockets do not make it into space. Those who fund SpaceX have a stake in seeing the best, most efficient rockets and missions fly- those who fund NASA do not; just the budget to fund the space pork and bring home the bacon. LOP-G is the latest wasteful pork project, and we should not be dazzled by the words “Moon space station” but ask instead what else could have been done with 9 billion dollars (That’s 145 falcon 9 rockets, or 100 falcon heavies). It is time to ditch the old way of space pork and use money more wisely.