Rocketdoc Notes – Week of August 23, 2020

Schedule for the Development of Space

I’ll give you a rest from the Drake equation this week and talk about something near and dear to my heart, namely exploitation and settlement of space. Science fiction has been writing about this since the 1940s (and earlier), but eighty years later it still hasn’t happened. Why not?

It hasn’t happened because it still costs too much to put a payload into Low Earth Orbit (LEO).

Why is that? We need to transition to reusable launch vehicles (RLVs) before space will be accessible to all. You can afford to own a car because the cost of the car is amortized over thousands of trips across town or to work. A trip across town in your car costs roughly $6 or about 3 cents per pound of payload. You can afford to fly across the country because the very expensive airplane you flew on is amortized over tens of thousands of flights, so the cost of each flight is primarily the cost of fuel, crew, and maintenance. A trip across the country costs roughly $400, or about $2 per pound of payload. However, right now, the cost of the vast majority of space launches is primarily the expensive launch vehicle that gets thrown away during each launch, while the cost of propellants and launch operations is a small fraction (< 10%) of the total launch cost. A trip to Low Earth Orbit (LEO) costs about $100M, or about $5,000 per pound, and if you were lucky enough to ride on the space shuttle, the cost for one launch was about $500M or about $10,000 per pound.

Space-X is changing the paradigm by reusing the first stage and fairings on its F-9 launcher and could probably sell cargo to LEO for slightly less than $1000/pound and still break even. The next step in work is the Starship/Heavy Lifter combination that promises 100 metric tons (220,000 pounds) to LEO for about $20M per launch or $90/pound. At $90/pound space development will be like the Oklahoma Land Rush. I was part of the Commercial Space Transportation Study back in 1993 when the new business groups for all six major aerospace companies combined forces to determine what space businesses prospered if we could get launch costs below $500/pound. This is shown pictorially in figure 1 below from the 1993 CSTS Study. The yearly $4.5B revenue shown for $100/pound was a projection for the year 2000. Given Moore’s Law, it should be an order of magnitude greater today. Note, that at $100/pound nearly all of the revenue is from space businesses not from the launch services.


Figure 1 – Elasticity of the Future Space Market


What are these LEO markets? They are LEO Tourism (where tourists who have been everywhere on Earth can claim bragging rights), LEO manufacturing (where unique substances can be assembled with disparate densities in Zero-gee and a perfect vacuum is available behind the wake shield for epitaxial film growth of computer chips), and zero-gee biological testing where experiments can be conducted without cells clumping due to gravity. This just touches the many variants we discovered during the CSTS. See the CSTS Final Report for details. The timing for ETO markets depends on when the Starship becomes operational. Elon says 2022 and I’m guessing 2024 based on my previous experiences with hot metal structures.

The buildup in LEO traffic will drive up the number of launches per year and this will reduce the cost per flight enough to allow lunar mining to proceed profitably. The seniors in my 2012 University of Washington Astronautics 420 Class studied lunar mining in detail with my help, and they proved to me that if you developed the required technologies in advance, and were willing to spend the first seven years losing money, the Net Present Value ROI was 36% which justifies the risk involved. See figure 2 below for a Cost-Profit Comparison over the 20-year planned program. The principal product mined from the lunar regolith was Platinum Group Metals (PGMs) with secondary products oxygen, water, hydrogen, nitrogen, and Helium3. The PGMs and Helium3 went back to Earth in capsules tossed by a giant sling and the other products were utilized for rocket propellants for a reusable lunar lander and the support base habitats.

Figure 2 – Cost-Profits Comparison for a Lunar Mining Program

The timing for Lunar Mining is about ten years after the LEO land rush occurs. That places it at about 2032 and it’s about the time current mining efforts will become unprofitable because of declining ore quality.

Thanks for your attention.

Dana Andrews

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