Last Friday, NASA awarded a $3.4 billion contract to a team led by Blue Origin for the design and construction of a second Human Landing System to fly astronauts down to the Moon.
The announcement capped a furious two-year lobbying campaign by Blue Origin owner Jeff Bezos to obtain a coveted piece of NASA's Artemis program. NASA also notched a big win, gaining the competition with SpaceX it sought for landing services. But there is a more profound takeaway from this.
After losing the initial lander contract to SpaceX two years ago, Blue Origin did not just bid a lower price this time around. Instead, it radically transformed the means by which it would put humans on the Moon. The Blue Moon lander is now completely reusable; it will remain in lunar orbit, going up and down to the surface. It will be serviced by a transport vehicle that will be fueled in low-Earth orbit and then deliver propellant to the Moon. This transporter, in turn, will be refilled by multiple launches of the reusable New Glenn rocket.
To be sure, that is a lot of hardware that has yet to be built and tested. But when we step back, there is one inescapable fact. With SpaceX's fully reusable Starship, and now Blue Moon, NASA has selected two vehicles based around the concept of many launches and the capability to store and transfer propellant in space.
This is a remarkable transformation in the way humans will explore outer space—potentially the biggest change in spaceflight since the Soviet Union launched the Sputnik satellite in 1957. It has been a long time coming.
"We knew these were the right ideas decades ago," said George Sowers, a professor of mechanical engineering at the Colorado School of Mines. "It is gratifying to see folks coming around."
What’s the big deal?
For pretty much the entire history of spaceflight, humans have tried to brute force things. It took a rocket to put a small satellite into space. It took a bigger rocket to launch humans. And it took the humongous Saturn V launch vehicle to ultimately put two humans on the surface of the Moon. The plan was always to pack everything needed for a mission—including propellant—onto a single rocket.
But this turns out to be a really, really inefficient way to do things. Imagine you want to drive from Miami to Alaska without stopping at a gas station. Even with an efficient automobile, it would take about 150 gallons of gas. Well, a tank that big won't fit into your trunk. No problem—you'll drive a full-size pickup and put a 250-gallon tank in the bed. It fits, barely. But there's a problem. You've added an extra ton to your truck, and your fuel efficiency drops. So now you have to pull a large trailer with an even larger gasoline tank. This is the tyranny of the rocket equation.
"The further you want to go in space, the mass of the propellant increases exponentially," Sowers said.
Large rockets can also be incredibly expensive. For example, NASA's Space Launch System rocket alone costs more than $2.75 billion per launch, and that doesn't include the price of a payload.
The solution to this problem involves several steps. The first is distributed launch. Two Falcon Heavy rockets, or four Falcon 9 rockets, can launch as much mass as NASA's Space Launch System rocket. The price for either option would be substantially less than $275 million, or one-tenth the cost of a single NASA launch. This exists today, and more partially reusable rockets are on the way.
The second technology is storing and transferring fuel in space, known as propellant depots. SpaceX and Blue Origin need liquid oxygen to serve as an oxidizer for their engines, but each uses a different fuel: methane for Starship and hydrogen for Blue Moon. Both companies have work to do in proving out the technology to store and transfer these propellants, but both have already been partnering with NASA. Sowers believes this is a solvable problem.
The third breakthrough, which unlocks the potential of this new spaceflight paradigm, is harvesting resources in space. This means tapping into the water ice believed to exist in abundance at the lunar poles and the ample ingredients for methane in the Martian atmosphere. The work is already happening here. Blue Origin has won several "Tipping Point" grants from NASA to demonstrate liquid hydrogen and oxygen production on the Moon, and with its MOXIE experiment, NASA has already produced oxygen on Mars.
Today there is great interest in the satellite community in the potential of in-space refueling. Lockheed, Maxar, and Northrop Grumman are all building refueling capabilities in their newer satellites. And companies like Orbit Fab and Astroscale are developing technologies to actually go up and deliver propellant. The economics make sense. If it costs $10 million to refuel a large satellite for three years and that satellite is delivering $100 million per year, the decision is a no-brainer.
With its choice of Starship and the revamped Blue Moon lander, NASA is dramatically expanding the concept of refueling into space exploration.
Why now?
If distributed launch, propellant depots, and harvesting resources on other worlds make so much sense, why hasn't NASA pushed for this activity before now? The answer is largely a political one.
For two decades after the Apollo Program, NASA was content to fly the space shuttle into low-Earth orbit. But after a second fatal accident—of Columbia in 2003—the space agency and policymakers started talking in earnest about what would come next.
Some engineers, like Sowers, began to think seriously about propellant depots in this era. Sowers worked at Lockheed Martin in the early 2000s, for a time serving as the chief systems engineer during the development of the Atlas V rocket. He also participated in the company's planning for what would become the Orion spacecraft. An early iteration of Orion, he said, was powered by a hydrogen propulsion module that could be refueled in space.
As part of this, he and others at Lockheed began researching distributed launch concepts and putting engineering rigor into propellant depots. They presented papers at space conferences held by The American Institute of Aeronautics and Astronautics, and the idea began to gain credence in the space industry.
"That was the first time I got into trouble," Sowers said.
The trouble came from NASA Administrator Mike Griffin, who was putting together a plan, called Constellation, to return to the Moon. It was based on the launch of a single, massive Ares V rocket, and he called it "Apollo on steroids." The depot idea was shut down for a few years until President Obama appointed Lori Garver to be deputy administrator of NASA. She was in favor of depots, and Sowers and others presented the concept to the Augustine Commission that reviewed NASA's human spaceflight plans.
Ultimately, however, Congress and the big traditional space contractors pushed back against the concept and killed it with the introduction of the large Space Launch System in 2010.
By this time, Sowers was working with Bernard Kutter in the advanced programs group at United Launch Alliance. The company was pursuing some innovative ideas that involved depots and a reusable rocket upper stage called ACES that was powered by hydrogen. However, United Launch Alliance is co-owned by Boeing and Lockheed, and Boeing was the prime contractor on the Space Launch System rocket.
When Sowers and his team released a series of papers showing how an architecture with refueling and depots would enable a human exploration program using existing commercial rockets, Boeing officials became furious and tried to get him fired. While Sowers was protected by his company's leadership, he was banned from uttering the word "depot."
At the same time, a powerful US Senator, Richard Shelby of Alabama, was adding billions of dollars to NASA's budget for the Space Launch System. This vehicle was being designed and managed at Marshall Space Flight Center in his home state. He, too, told NASA officials to stop talking about depots. Before then, NASA had been considering funding some experiments with United Launch Alliance on propellant storage in space.
Leveling up
Shelby retired at the end of 2022. One long-time advocate of propellant depots, Jonathan Goff, does not believe this is coincidental to the space agency's renewed interest in depots.
The German physicist Max Planck is credited with the notion that science advances only when older practitioners die off, leaving room for new ideas. The philosopher of science Thomas Kuhn more pithily summarized the sentiment by writing, "Science advances one funeral at a time."
Goff offered a variation on this idea for spaceflight: "Space policy seems to progress one congressional retirement at a time," he said.
Like Sowers, he welcomed NASA's entry into an era of reusable spaceflight. But Goff noted that it is really only happening because two billionaires, Elon Musk and Jeff Bezos, are aggressively pushing the idea forward.
NASA has spent so much over the last decade on the development of the SLS rocket—north of $40 billion, including ground systems—that there has been little money left over for exploration payloads to fly on them. Therefore, when it came time to fund the lunar landers, NASA had to go with the least expensive options. Both Starship and Blue Moon are, roughly, at least $10 billion development programs. But because it can purchase them with fixed-price contracts, NASA is only paying about a third of the overall cost for both, $6.3 billion.
"The only way NASA could really afford to do this was by not doing business as usual," Goff said.
Although developing Starship, Blue Moon, and their refueling capabilities will be challenging, Goff said they are engineering projects and not basic science. In other words, we know this will work. Humans have built plenty of rockets before, and with the Falcon 9, we know that rapid reuse is possible. The physics and engineering of propellant storage and transfer is solid; it just needs to be done.
"I think we could have done a lot of this in the 1960s if we had put our minds to it," he said. "The only reason we haven’t done it by now is because it’s hard to get the money to do it. Until now, most people assumed a big rocket, like with Apollo, was the only way."
But it's not. If humanity wants to level up as a spacefaring species, this is the clear path forward.
Finally, we are walking it.
