We Space Tweeps were all intently watching Twitter today taking in the sites and sounds of the latest meeting of the Augustine Committee on Review of U.S. Human Space Flight Plans. Someone brought up a very valid point during the ongoing reporting and discussion that made me realise I’m not alone…

Time and time again I read about the limitations of needing a Heavy Lift platform to launch space missions. One of the biggest hurdles to the mission to Mars is looking like its going to be actually getting it off the surface of the Earth.

The answer is simple, and what is more it’s been staring us in the face for decades. Every great sci-fi movie or even video game I’ve seen, space faring vessels are constructed out in space using some kind of dry dock or something similar. Why? Because it looks impressive? Yes.. and no. See the reason is it make perfect sense. The problem with being on Earth is you’ve got to get off Earth to go anywhere. That’s okay if you are 3 guys in a computer-guided coke can going for the first moon shot in 1969, but that was 40 years ago. This is 2009 and some day soon we’re gonna want to do bigger and more long-term things… like go to Mars.

See my immediate thought is that a Mars mission is gonna require a BIG vessel. It takes a few days to get to the moon and a few more to get back. Shuttle missions usually last 1-2 weeks. In the name of science and space exploration a few human beings don’t mind being couped up in a shoebox for a while, living on top of each other etc. but for months on end on a journey to Mars? You’re gonna need space for food, water, facilities, life support, mission supplies etc. You’re gonna need crew quarters that make the long journey comfortable and feasible. People together for that length of time are going to need some kind of privacy or personal space, as well as 

Well you have 2 options:

You could make a very heavy and complex vehicle that can be launched from earth using a huge heavy lift system. Look at the logic though. You need to develop the mother of all rockets to launch it. The spacecraft itself will need to be large enough not to drive the occupants insane, carry fuel, life support and supplies for a long mission and carry a landing vehicle if the mission requires it (I’m presuming we want to land don’t we!?). The possibly worst part to think about is what if something goes wrong at launch? You;ve lost a 100s of billions of dollars of taxpayer’s money, an expert and trained crew and the public’s confidence. You couldn’t do the ‘oops, sorry, we’ll do a safety review and try again’ thing with this, it’s not the same as Apollo. 

The alternative, and in my book vastly more feasible idea is to build a spacecraft in orbit, either around the Earth or around the Moon, attached to a space station and a a dry-dock. You fly the parts up a bit at a time a-la the International Space Station, you put the modular items together in space and when it’s finished you fly it to Mars. The advantages are many:

  •  You don’t need a massive heavy lift launch vehicle – something reasonably capable that was say also usable to get to the Moon, would do the job of transferring people and parts to orbit for construction.
  • The construction teams would be able to live in orbit and modules flown up to them. We can already do that now.
  • You don’t have to make the unit fit on top of a rocket system, it doesn’t have to be aerodynamic on any way, or be shaped to fit inside the faring.
  • It doesn’t matter about the weight. As long as you can bolt a big enough engine system to the back to get the mass to Mars it’s not a big issue.
  • Although admittedly a little tricky, the *potential* is there to reuse part or all of the spacecraft just by tethering it in space then reconditioning it.
  • If something goes wrong on a supply/crew launch there is potential loss of human life, but this is a risk we always take. On the up-side also a lot of the flights will be unmanned a-la Progress. If a module is lost then only a fraction of the spacecraft is lost, and it can be remade. It might cause a delay but ultimately it’s only a setback, not a catastrophic dead loss of crew and craft.

So when you look at 2001: a space odyssey and the ‘Discovery I’ spacecraft that took HAL and his crew to Jupiter, you might be looking at potentially our Mars taxi. I admit constructing a spacecraft to travel to Mars in orbit around a body, then make it good to fly to another planet isn’t without it’s challenges, but the possibilities and the potential it unlocks for our future in space is massive!