Feasibility Study Of Earth Launches To Deep Space
Whilst human space exploration has been in stagnation, if not decline, since the 1960’s, as is represented by the percentage of the US federal budget being devoted to NASA, recent ‘stunts’ and technological developments by private space-faring companies have recaptured the public interest in space travel, both for scientific and leisure purposes.
Scientifically, in the face of dwindling natural resources and global climate change there may be a need for a sudden increase in the exploration and exploitation of space and celestial bodies for their natural resources and minerals. Proposals also exist for methods of reducing climate change by using “Space-sun reflectors” (Chandler, 2007). This concept suggests that by placing a large body, or lots of smaller bodies, between the Earth and the Sun would reduce the amount of solar radiation reaching and therefore warming the Earth.
In a study done on the use of “solar flyers” at the inner Lagrange point (L1) it is proposed that if flyers were launched in batches of 1000 it would take between 21,350,000 to 23,375,000 launches to produce the desired coverage and cooling effect (Angel, 2006) (Grainger, 2018). These initial launches would then need to be supplemented by an additional 135,000 launches every year afterwards in order to maintain the flyer cloud density. If this proposal was to be completed within a 10 to 25 year timespan it would require an annual launch rate of between 935,000 to 2,135,000 launches per year. (Grainger, 2018)
Given that since 2010 there have been 51 launches made by NASA’s Launch Services Program (LSP) (_) it is clear that there is currently insufficient infrastructure to support such an endeavor.
Whilst significant investment could be made into the improvement of the current launch system, expendable launch vehicles (ELV), these conventional rockets are, by their very nature, inefficient. On the launchpad the majority of their mass is comprised of the propellant and structural support required to launch them, which also must be accelerated along with the payload.
For example, the Saturn V rocket which was used to launch the Apollo 11 mission in 1969, amongst others, had a takeoff mass of 6,477,875 lb (NASA, n. d. ) or 2,938,315 kg. The Command and Service Module (CSM) payload it carried had a total mass of 109,646 lb (NASA, n. d. ) or 49,735 kg. This quite simply shows that at launch only 1. 69% of the rockets total mass was the actual payload. More recently, the Space X Falcon Heavy has a mass of 1,420,788 kg and advertises a maximum payload capacity to Low Earth Orbit (LEO) of 63,800 kg (SpaceX, n. d. ). Whist this is significantly better than the older Saturn V rockets it is still only 4. 49% efficient, in terms of mass.
Technological developments have allowed for the development of reusable launch vehicles (RLV), such as the Space X Falcon Heavy, that mean the fuel tank structures can be reused as it is capable of automatically returning and landing on Earth after launch. Whilst these increase efficiencies and reduce the launch costs it does not solve the efficiency issues caused by carrying the propellent.
However, ideas for alternative methods of space launch have been theorized since 1865, both in fact and in fiction (Verne, 1865). Since then many other concepts have been developed but non-are yet to be fully realised. In the light of the potential need of natural resources and solutions to global warming these concepts and thought experiments may prove to be the only feasible solutions.
