Breaking out of the eggshell

    It may sound strange, but most of the energy consumed by any spacecraft is used for getting out of our atmosphere. But this is logical: Earth’s gravitational pull is much stronger, and there’s also friction with the atmospheric gases, which makes it much harder to move than in interplanetary space. And there’s more. For lifting a certain mass, you need an amount of fuel, but that also has a weight, and you need more fuel to carry the ensemble. The result: huge amounts of fuel for limited payloads.

   When you see a space shuttle, you surely notice that it has a huge external tank and rocket boosters, which together are larger than the shuttle itself. They only contain the fuel needed to exit the atmosphere. And they are not reusable. So, for every launch, NASA needs to produce such tanks and fiil them with a huge amount of fuel.

   So, in order to become a truly spacefaring civilization, we must find an inexpensive way to get into orbit. The first idea that strikes us is using a cannon. Actually, a huge railgun. This is the “Bifrost” Project coined by M.T. Savage (check the LUF website). Surely, this would also consume huge amounts of energy. The advantage is that spacecraft won’t need to carry all that fuel with them.

   Another method would be to have a direct connection to a low-orbit launch station. One way to achieve this is by space elevators. However, building such structures is a daunting task. Just consider that no material known to man could support the mass of some thousand-kilometer-cable. Except for carbon nanotubules, that look promising, but that we are unable to produce on a large scale.

   A far more interesting (and really impressive) proposal is the StarTram Project, which, according to its supporters, would lower launch costs to less than $40/kg and would allow transporting millions of people in space each year. Basically, it’s a MagLev train that reaches a low-orbit station, from where the journey continues by conventional spacecraft. The trick is that the railroad itself would be magnetically levitated to a certain angle. This would certainly consume lots of energy, but it’s a good way to hold such a high structure above ground.

   So, both Bifrost and StarTram projects look promising, and they would certainly solve one of spaceflight’s gratest problems. Building such structures would surely need huge (i.e. international, mostly state-supported) investments, but for now it’s the only way to achieve true spaceflight efficiency and send sicnificant amounts of material and people to colonize the Solar System. In order to begin exploring and exploiting the universe’s vastness, we first need to break out of our atmospheric eggshell.