Gas Stations in Space?
We can’t do anything ‘worthy of a great nation’ within the current human spaceflight budget.” This is how many, both in Washington and elsewhere, are interpreting the findings of the Augustine committee, appointed by U.S. President Barack Obama to rethink the future of human spaceflight. They apparently believe Moon and Mars trips are the only exciting things a space program can do — and that only the government can do it. So they conclude either that government needs to spend lots more money so we can do something worthwhile, or that we need to accept dramatically more modest, and less expensive, goals.
Intriguingly, the report also contains hints of other paths. It tells, for example, of the benefits that arise “from the development of in-space refueling,” suggesting that the best way to create this capability is to have a “government-guaranteed market for fuel in low-Earth orbit.” Government guarantees and orbital gas stations hardly seem exciting, but let’s take a closer look.
Before I do, however, I’d like to take a moment to address the nitpicking rocket geeks who are going to be flaming me if I don’t specify that when the Augustine report says “fuel” it clearly means “a variety of fuels and oxidizers.” I find this a sensible semantic simplification that I intend to follow.
I also need to address the objection that refueling adds complexity to space missions. This is clearly true. It also would be simpler to sell new cars loaded up with enough fuel to last for the planned mission life of the vehicle, thus avoiding the need for a complex network of dangerous and expensive gas stations scattered across the global landscape. Sometimes the advantages of simplicity are overwhelmed by the benefits of a bit of complexity.
Fuel depots fundamentally change the economics of going beyond low Earth orbit. A lighter and drastically cheaper spaceship can be sent to low Earth orbit with empty tanks and fueled up before continuing on its way. (Readers wanting detailed numbers on this can find them on page 65 of the Augustine report. Discussion of the required technologies begins on page 100.) Even better is the potential to refuel returned spaceships so they can be reused for multiple trips to deep space destinations, saving even more.
The Augustine report also examines how “refueling introduces the idea of critical launches and less critical launches in any given mission.” If it takes several launches, all of which need to be successful, to accomplish a given goal, the overall risk of failure climbs significantly. Since launches carrying the fuel can occur long before a final commitment is made to launch critical components, the overall risk is reduced, even if the system used to launch fuel has much lower reliability.
Because fuel depots can be supplied by almost any size launch vehicle, they spur competition, innovation and price reductions in Earth-to-orbit transportation. Since governments are the largest consumers of such services — primarily for defense, but also for environmental remote sensing and civil space — taxpayers are the main beneficiaries of these cost reductions.
Once a market exists for fuel transported to low Earth orbit, there inevitably will be entrepreneurial efforts to use extraterrestrial resources to manufacture fuel in space for use in space. Both the Moon and some near-Earth asteroids contain the basic components of most types of rocket fuel, as well as numerous other valuable resources. Many of us are convinced that these resources can be mined and processed for significantly less cost, and dramatically less environmental impact, than transporting them from the surface of the Earth. If these efforts prove profitable, we will have our first space mining and manufacturing operations — the first steps toward expanding human civilization into the solar system.
After rocket fuel comes electricity. While we may one day use the abundant, unfiltered, 24-hour, high-noon sunlight in space for radio transmission of electricity to Earth, the near-term opportunity is to use that energy for the kinds of satellites that we already have in space. The technology we develop to supply our fuel depots will enable us to manufacture electrical generators made mostly from raw materials found in space. This further reduces costs and increases capabilities.
It gets even better. Most satellites today cannot be maintained on orbit. But if we are able to mine and manufacture fuel and generate electricity in space, we could dramatically extend the life and capabilities of a new generation of satellites, in much the same way that we have done for the Hubble Space Telescope.
Fuel, electricity and satellite maintenance lead to many more potential markets, some of which nobody today can possibly foresee. Costs keep dropping; capabilities keep rising; more markets open up.
Which do you find more worthy of our great nation: a few dozen government boots planted on the Moon and Mars, costing taxpayers millions for each footprint, or whole new industries, creating millions of high-paying, private-sector jobs, building the means to get paying customers to the Moon, Mars or anywhere else they can afford? The first step toward one requires a big jump in federal spending. The first step toward the other is a “government-guaranteed market for fuel in low Earth orbit” that both increases capabilities and saves money.
Bob is the chairman of the board of the Space Frontier Foundation, an organization of people dedicated to opening the space frontier to human settlement.