“The picture that emerged out of those meetings was that you could create a permanent, economically self-sustaining presence on the moon that could be done for the single-digit billions,” said Steve Jurvetson, a venture capitalist, who provided the initial Open Lunar funding.
Improving Zubrin’s Moon Direct Plan Would Be the Starting Point
Launch costs and non-launch costs could be roughly equal. Moon Direct setup missions (two flights for Phase 1 and two Phase 2 missions) could cost about $1.5 billion. Recurring missions will cost $420 million per year. This is two percent of NASA’s current budget. This is very inexpensive by the standards of human space programs. NASA’s human spaceflight program total budget is currently around $10 billion per year with little clear purpose.
Robert Zubrin, a New Atlantis contributing editor, is president of Pioneer Astronautics and of the Mars Society. Robert Zubrin, “Moon Direct,” The New Atlantis, Number 56, Summer/Fall 2018, pp. 14-47.
The Lunar Orbital Platform-Gateway (formerly known as the Deep Space Gateway) is receiving some money. The gateway will be a waste.
Some areas on the moon have water ice concentrations of 30 percent by weight in the topmost layer of soil.
● Phase 1: Unmanned missions deliver the materials for the lunar base to the Moon.
● Phase 2: Piloted missions make the base operational. A key objective of this phase is to bring propellant production online and make it continuously available.
● Phase 3: This is the long-term phase, with recurring piloted missions using propellant produced on site.
In Phase 1, two Falcon Heavy boosters are used to deliver the materials for the base and other cargo to the Moon.
In Phase 2, one Falcon Heavy and one Falcon 9 are used to deliver the crew to the Moon in a fueled LEV.
In Phase 3, only one Falcon 9 is used to deliver a new crew to orbit in a Dragon 2, exchange crews, and refuel the LEV. The new crew then flies to the Moon in the LEV, which refuels again at the lunar base, while the Dragon 2 returns to Earth with the previous crew.
Producing water and fuel on the moon
The top priority is propellant production. Each Moon Direct mission requires 6 metric tons of propellant to be made on the Moon for the LEV’s flight back to Earth orbit. It also requires 6 tons of propellant for each long-distance surface sortie from the base to a distant location on the Moon and back. For purposes of analysis, we will assume that once the base is operational, every fourth month there will be a round-trip mission from the Moon to Earth to exchange crew, and in each other month there will be one long-range exploration flight. The propellant manufacturing requirement will be 6 tons per month or 200 kilograms per day.
Engines running on liquid hydrogen and liquid oxygen use a higher ratio of hydrogen to oxygen than what is found in water. To get our 200 kilograms of propellant, we would need to electrolyze around 260 kilograms of water (about 70 gallons) per day. The happy side effect is that this would leave about 60 kg of leftover oxygen every day, which could be used for crew breathing supply.
The dominant power requirement will be for vaporizing and electrolyzing the water. To electrolyze 260 kg of water per day will require 56 kilowatts of power. We can estimate that water could be vaporized at the same rate using beamed microwaves with about 26 kilowatts of power. Cryogenic liquefaction of the hydrogen and oxygen products — aided by the extremely cold temperatures on the Moon — will add about 25 kilowatts, and life support and other equipment will also add another 13 kilowatts to the power needs. The estimate is 120 kilowatts for our total power requirement. This could be supplied by either a solar array or a nuclear reactor. Either solar or nuclear can be built with 4 tons using proposed technologies.