Walmart, But for Space

Cheapness isn’t just about rockets — it will change the design of everything we send up.
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The “billionaire space race” may have blasted to public attention in the summer of 2021, but it was decades in the making. Richard Branson, who took a suborbital flight on July 11, founded his company Virgin Galactic in 2004 to build on technology developed for SpaceShipOne, the first privately built vehicle to carry humans to space. Jeff Bezos’s own suborbital trip on July 20 was the first crewed spaceflight sent up by Blue Origin, the company he founded in 2000 and funded with his Amazon earnings. Elon Musk’s SpaceX — which spent the summer launching satellites, restocking the International Space Station, and preparing for a tourists-to-orbit charity flight — was founded back in 2002 with his profits from selling his share of PayPal. Through the summer of 2021, the three men took jabs at one another in press releases, social media posts, and legal filings.

The billionaires’ bitchy tit-for-tat titillated journalists, and critics reveled in mocking the whole spectacle as a series of gaudy, priapic stunts, extravagant symbols of decadence. Largely lost in the public discussion has been the broader context of the new space race: the rapid transformation of space from an arena prohibitively costly for all but the deepest pockets into one much more widely accessible to private enterprise and human creativity.

For all that we’ve accomplished in space over the past six-plus decades, our activities have always been constrained by the historical economics of rocketry. In the 1960s, the U.S. government was willing to get to the Moon by the most expensive means possible, so long as we got there first. Then came the space shuttle program, which failed to reach the promised level of increased flights and reduced costs. Following the deadly Columbia disaster, the space shuttle program was wound down. But now, a decade after the last shuttle flight, we are on the verge of dramatically reducing the cost not only of getting into orbit but of manufacturing the payloads necessary for much more advanced space accomplishments and commerce. What are the implications of this for finally opening the high frontier, and how much more could we have accomplished if we had done it sooner?

High Costs Beget High Costs

To understand why space activities are about to get so much more affordable, it is important first to understand why they were for so long so expensive that space was almost exclusively the province of governments.

The fundamental driver of high spaceflight costs is that we have always thrown the rockets away. Imagine how many millions of dollars an airline ticket would cost if, at the conclusion of every flight, we destroyed the aircraft. Yet that is more or less what we have done in space: discarded the expensive machines that brought us there. As a result, rocketry has cost millions of dollars per flight, and thousands of dollars per pound of delivered payload.

The infrared Spitzer Space Telescope stands in a clean room at the Kennedy Space Center. It launched on a Delta II expendable rocket in 2003 and retired in 2020.
NASA / Wikimedia

When launching a satellite costs thousands of dollars per pound, you will spend a lot of money to reduce its mass, both so that it can be delivered by a given rocket and so you can get the most bang for your launch buck. In turn, this means miniaturizing components as much as you can, using exotic lightweight materials, and spending a lot of design time to package things as efficiently as possible. All of this greatly increases the cost of a satellite compared to analogous ground-based devices. And because the satellite is now very expensive, it has to be highly reliable and long-lived, to minimize the risk of having to build a replacement and launch it into orbit, each of which costs a lot of money. This means using the highest-quality components and adding redundancy, which further increase cost.

So now we have a very expensive satellite, which means that the rocket that launches it must be extremely reliable so that it doesn’t drop the pricey bird into the Atlantic. Making a launcher more reliable costs a lot more than making one that is less reliable. It requires, among other things, redundancy of subsystems, highly reliable components, and rigorous quality control in manufacturing and operations. As the launcher — which, remember, will be thrown away — gets more expensive, pressure increases on the satellite designer to reduce mass and boost lifespan and reliability.

But there is yet another factor that feeds into this cycle. Expensive activities will be done less often than inexpensive ones. With limited budgets, even for government agencies, the high cost of building and launching satellites means that spaceflight will be infrequent. The cost of a launch must include not just the rocket and payload itself, but also the fixed costs for the facilities and launch personnel. If the flight rate is low, the fixed costs will be spread across fewer launches, which drives the cost of each launch still higher, in turn making payloads that much more expensive.

Another obvious problem with throwing away rockets is that, while it can work for delivering payloads to space, it is of no help in bringing payloads from space. Getting mass down to the surface from space requires entry capsules, which are expensive to build and launch, for the same reason other satellites are. They have a much smaller payload capacity than the rockets on which they go up. For example, each expendable Saturn V rocket sitting on the launch pad during Apollo weighed some 3,000 tons. It could deliver 45 tons to the Moon. But the payload brought back from the Moon was just three astronauts and a couple hundred pounds of rocks.

The much higher cost of returning mass compared to delivering it has meant that the only commercially viable orbital payloads to date have been satellites that can deliver value back to Earth via massless photons, as communications and remote-sensing satellites do. And of course, things like space tourism have been out of the question. This further restricts demand for space access, keeping its costs high through low flight rates.

Hence the vicious cycle that has dominated the history of spaceflight: Expensive rockets beget expensive payloads, which beget more expensive launch prices, which inhibit both government and (even more so) private space activities.

Rapidly Reusable Rockets

Let’s return to the difference between aviation and current rocketry. For an airliner, fuel cost is typically between 30 and 50 percent of the total cost of the flight, in addition to crew, maintenance, depreciation, and other costs. To save just a few percent on fuel consumption, aircraft designers will make changes in new aircraft, such as the winglets one sees on most modern passenger jets. Even such marginal improvements to fuel efficiency can make a meaningful difference to the airline’s bottom line.

For an expendable rocket, propellant cost is less than 1 percent of the total cost per flight. So clearly, if we want to make spaceflight anywhere near as affordable as air travel, we have to get the cost of the things that are not propellant down to a level at which the cost of propellant becomes as significant as it is to an airline, and like them, we start to care about it. If we can do that, the problem has been solved, because it means that the total cost per flight has come dramatically down, by orders of magnitude.

From the founding of SpaceX, Elon Musk recognized that the key to his dreams of sending humans — including himself — to Mars was a dramatic reduction in launch costs, and that the key to reducing launch costs was to stop throwing away the hardware with every use. NASA’s space shuttle system had been partially reusable — including the orbiter, which landed like an airplane — but the overall design was cost-ineffective and unreliable. Musk wanted a better way of breaking out of the vicious cycle of high costs begetting higher costs. In 2015, after many previous attempts, SpaceX successfully touched down a first stage of its Falcon 9 rocket on its tail. No one had ever sent an orbital-class rocket to space and landed its booster before. Soon such landings became the norm for SpaceX. They are newsworthy now only on the rare occasion when they fail. SpaceX began reusing those first-stage boosters in 2017, and by May 2021 had flown one of them ten times, meeting the original goal the company had set for reusability. As of this writing, more than 85 percent of the dozens of Falcon launches in 2020 and 2021 used previously flown boosters.

SpaceX has also begun recovering payload fairings — the nose cones atop the rockets — saving about $6 million per reuse. The only part of its rockets the company cannot now recover is the upper stage that delivers payloads to orbit.

But that, too, is about to change. SpaceX has been testing a new two-stage space transport, the largest rocket ever built, that will be fully reusable. It is being designed to require little maintenance between flights, except refueling — like an aircraft. The first stage, which is planned to have its first flight in fall 2021, is called Super Heavy. It will land vertically as the Falcon booster does, after delivering the second stage, called Starship, to its prescribed altitude and velocity. Starship itself will be able not only to enter the atmosphere from space and land on its tail, but with in-space refueling, go all the way to the Moon, Mars, and other interplanetary destinations. The vehicle was recently selected as the lunar lander for the Artemis program to return NASA astronauts to the Moon. After several earlier test flights, Starship performed a successful high-altitude flight on May 5, 2021, landing intact with only a small fire at the base, which was quickly put out. The company’s goal is to get Starship to orbit in 2021 using the Super Heavy booster. If it does so — and if the company can demonstrate that its new heavy-lift rocket is not just reusable but, in Elon Musk’s words, rapidly reusable — it will revolutionize spaceflight.

(It is worth noting that a strong commitment to increased reusability does not mean every mission will be designed to have the booster recovered. Occasionally disposing of a vehicle may be necessary for meeting performance goals for a given mission.)

Because the largest part of the marginal cost of each flight is for propellant, Starship will be able to deliver a hundred tons to orbit for just a few million dollars per flight. Compare that to the tens of millions of dollars that a Falcon 9 costs, even with partial reusability, for much less payload. Once the new system’s reliability is demonstrated with a large number of flights, which could happen in a matter of months, it will obsolesce all existing launch systems.

Put it another way: It cost between $10,000 and $30,000 for NASA’s space shuttle to deliver each pound of payload to orbit. On the biggest rockets that conventional commercial aerospace firms currently operate, the Atlas V and Delta IV, the cost per pound is between $3,000 and $7,000. SpaceX, with its increasingly reusable Falcon vehicles, has already brought that figure under $1,000. Now suppose that SpaceX charges $10 million per flight on its new Starship/Super Heavy system. That works out to about $50 per pound of payload to orbit.

To get a sense of what such a radical cost reduction makes possible, let’s go back to satellites. If I’m paying only $50 per pound to deliver one, and it can be pretty much as big as I want, how does my design philosophy change? Well, I’m not going to spend more than $50 to get a pound out of the bird. For example, I’ll build it out of cheaper aluminum instead of carbon composite. I won’t pay an expensive designer to figure out how to package it to fit inside a small fairing. Moreover, I won’t pay orders of magnitude more for extremely high reliability and long life, because I won’t have to worry as much about the cost of building and launching a replacement if it fails. This has been the philosophy of the remote-sensing company Planet. Its tiny “Dove” satellites — basically cell phones with solar panels and attitude-control systems — only last a few months and are continually replaced by improved versions as the old ones burn up on entry.

Building a Future in Space

But we can take it a step further. The most perilous part of a satellite’s lifespan is its trip into space, with all of the intense acoustic vibration of rocket engines that are putting out thousands of pounds of thrust. Engineering a satellite to survive this journey requires increasing its mass to make it more resilient. If it had a gentler ride, it could be much lighter, because structural stress in the freefall of orbit is minimal. Building gentler chemical rockets isn’t feasible, but several companies are developing the capability to build satellites in space: Redwire and Tethers Unlimited, for example, are working on robots that can assemble structures in space, while Kleos is testing a technology that can manufacture long composite beams with embedded power and data cables. Bulk cargo, like aluminum beams or solar panels, can withstand a lot of acoustic vibration, so a designer will have the choice of either building a more robust structure at a lower cost per pound, or building it in space, where it can be gossamer-light. And in the latter case, we will have finally defeated what is sometimes called the “tyranny of the fairing” — the need to fit anything we want to use in space into the rocket’s conical storage section. We will be able to build arbitrarily large structures, such as large space-based arrays for astronomy, or even satellites to collect the endless solar power in space and beam it to Earth. We may even use lunar materials for it; researchers are studying how additive manufacturing (that is, 3-D printing) would work on the Moon, using lunar regolith.

Either way, whether satellites are built on the ground or assembled in space, their cost will be orders of magnitude less per pound than those designed for current launchers. So not only the launches but the payloads as well are about to become almost unimaginably cheaper.

There is another way the radically reduced cost of launching payloads into space will be transformative: It will allow for the creation of “gas stations” in space. The reason the lunar module was expended after each of the six Apollo missions to the Moon’s surface was that it would have cost far more to send enough propellant to the Moon to bring the module home all the way than it cost to replace the module. Imagine you had to drive across the continental United States without refueling because there were no gas stations between the coasts. It can be done, but you would have to drive a tanker truck. And the fuel mileage of tanker trucks is terrible, because they have to haul not only the truck but all of the fuel needed to get cross country. The more often you can fuel, the smaller your vehicle and its propellant consumption will be; the ubiquity of gas stations means we can drive small cars all the way.

With gas stations in space — in low Earth orbit, in space around the Moon, and on the lunar surface itself — many kinds of activities in space and novel mission architectures become feasible. For example, to get the lunar Starship to the surface of the Moon with enough propellant to return to Earth, SpaceX proposes launching eight Starship tankers to fuel it in low Earth orbit. Ultimately, the plan is to do such refueling to send it all the way to Mars. As with ground transportation, with ubiquitous gas stations in space near Earth and beyond we will be able to get around the solar system more cost-effectively and with much smaller vehicles.

But where does the propellant come from? Initially, with payload costs on the order of tens of dollars per pound, it will be delivered from Earth. Even with the discovery of water on the Moon that could theoretically be made into oxygen and hydrogen for rocket propellant, the relatively low demand for propellant on the Moon and the relatively high cost of setting up the facilities to mine and process water could make the transport of fuel from Earth more cost-effective, at least in the near term. The situation is further complicated by the fact that the SpaceX vehicle, like some others, uses methane rather than hydrogen for fuel, which would require the import of carbon from Earth to manufacture. Ultimately, we will mine not just the Moon, but other bodies in the solar system for hydrogen and other needed resources. But in any event, in-space refueling is likely to be an essential component of space transportation.

Finally, consider the implications of a vehicle that can not only deliver a hundred tons to orbit but return perhaps half of that to Earth. This will make it possible to use space for more than just the transmission of data-bearing photons. Businesses will be able to employ manufacturing processes that require vacuum or weightlessness. For example, ZBLAN fiber-optic cable has been experimentally manufactured on the International Space Station with far fewer imperfections than on Earth, allowing it to carry much higher bandwidth, which would be of great value.

But the most obvious new use of this capacity is tourism, since most people who will be visiting space will want to return to Earth. This is already an existing market: SpaceX is now providing transportation to the International Space Station for NASA on Falcon 9 and Crew Dragon, Boeing is expected soon to follow with its Starliner on an Atlas V, and SpaceX’s first Dragon commercial passenger flight is imminent. But the cost per passenger runs into hundreds of thousands or even millions of dollars. At $50 per pound, the cost of a ticket to orbit could conceivably come down to few thousand dollars. In anticipation of this potential market, several companies — Axiom, Sierra Nevada, Nanoracks, and others — are already vying to build private space facilities.

A New Era

Our first six decades of space activities were characterized by high costs of access to space resulting in high costs for space hardware, with a transition to a different paradigm delayed by politics, institutional inertia, risk aversion, and perhaps a nostalgic clinging to a glorious past in which NASA sent men to the Moon — despite our failure to return there for almost half a century. But because some billionaires who grew up in that era decided that they were going to be more ambitious than the politicians were, we are finally breaking out. As a result, the near future of our space activities will reflect plunging costs of access, spacecraft, and space activities, finally forging the dreams that the orphans of Apollo have harbored through all those decades into a reality of hundreds or thousands of people living, working, and playing on the high frontier.

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