Dec 23, 2017
Launching rockets from the Moon is our ticket to a home on Mars
How our celestial neighbor can be an enabler of humanity’s future
Thousands of generations have looked up at the Moon in curiosity and wonder. From looking up at Moon to going there, we have come a long way. If we are to save ourselves as a species, we must colonize the Moon, a world we can call our second home.
Mars is certainly more habitable but the Moon can be the stepping stone towards a multi-planetary human presence. The following article explores what a first lunar colony can be like.
Humans as a multi-planetary species
The Moon has become a center of attraction once again with Russia, China, & Japan interested in having a moon base in the future. Trump’s announcement to send astronauts to the lunar surface rekindled America’s interest in the Moon. A multi-planetary species as imagined in The Expanse envisions permanent human outposts on a variety of solar system worlds like the Moon, Mars, Jupiter’s moon Ganymede and more.
Such a vast inter-planetary settlement requires sending lots (read LOTS) of material to those worlds. Establishing even a small permanent outpost on Mars would require sending hundreds to thousands of tons of material to its surface. This has to be done in the form of multiple launches, of the order of dozens to hundreds.
The core problem of rocket science
The more the payload a spacecraft has to carry, more the fuel required in the rocket to launch it. Since the inclusion of more fuel increases the weight of the rocket itself too, we need more fuel to carry that fuel. Rocket science.
As you add more weight to the spacecraft, the fuel requirements thus increase exponentially. This requirement is called the delta-v budget. The more the delta-v required, more the cost & technological complexity of a mission since more energy is needed to get out of the Earth’s gravitational influence/gravity well.
Sending hundreds of tons of payload per rocket to other worlds requires a really high delta-v from Earth. The engineering cost to achieve such an aspirational vision is going to be quite off the charts. This is where the Moon can help.
The Moon as a rocket platform
The following chart shows the delta-v (and thus energy) required to reach various points from the Earth and the Moon.
Going from the Earth to Low Earth Orbit (LEO) requires a delta-v of 9.4 km/s. A further delta-v of 3.2 km/s is required if the spacecraft has to free itself of the Earth’s gravity well. Notice that the Moon exists in the outer part of the Earth’s gravity well.
Combined with the Moon’s low gravity, the delta-v required to escape the Earth’s gravity well from the lunar surface is just 2.64 km/s, which is even less than what is required from LEO.
The lower delta-v required to launch stuff from the Moon has multiple advantages:
1. Accelerated growth
Lower delta-v means launching the same amount of payload from the Moon takes less fuel compared to Earth. Large rockets like Space X’s Falcon Heavy or the BFR can launch far more payload from the Moon than from Earth.
This accelerates the rate of deployment of a permanent base on any world where lots of material would be required to be carried in multiple launches. The total cost to put something out of Earth’s gravity well from the Moon can be 10x lesser than Earth’s.
2. Cheaper launches
Less fuel requirements also mean that less complex (less costly) rockets can do the job of escaping Earth’s gravity well and go to destinations like Mars easily. The lower costs also allow cheaper one-time launches like space telescopes, deep space missions and satellites.
Sourcing materials from the Moon
If we use the Earth as a supply to launch rockets from the Moon, it doesn’t make any sense since the total delta-v would be similar. Once we have a lunar colony though, the resources of the Moon can be utilized. Being able to launch rockets assumes that we are producing rockets and fueling them on the Moon itself.
The lunar soil can be a source of materials+minerals required to build rockets. Presence of water ice on the Moon greatly accelerates the ability to source the water for hydrogen which can be used a fuel propellant. Mining of Near-Earth Asteroids (NEA) can aid the manufacturing since these asteroids require very less delta-v to reach from Earth/Moon orbit.
Conclusion
The initial cost of a moon colony capable of building and launching their own rockets will definitely be high. But it is worth it in the long term. When you consider the hundreds of thousands of launches required to expand human presence in the solar system, the cost escalates quickly. The Moon as our rocket platform can drastically reduce the costs and allow for efficient development.
The Moon can be our long term rocket platform that puts us across the solar system.
Imagine a farm on Mars, a colony on Ganymede, a flight on Saturn’s moon Titan. Imagine.
