Blue Origin’s Next Rocket Engine Could Send the First Settlers to the Moon

In a cavernous building in Washington state, Blue Origin workers are constructing New Glenn’s BE-4 engine

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graphic link to special report landing page
graphic link to special report landing  page

Jeff Bezos, the founder of Amazon and the richest person on Earth, is of course a man who thinks big. But exactly how big is only now becoming clear.

“The solar system can support a trillion humans, and then we’d have 1,000 Mozarts, and 1,000 Einsteins,” he told a private aviation group at the Yale Club in New York City this past February. “Think how incredible and dynamic that civilization will be.” The pragmatic entrepreneur went on to say that “the first step [is] to build a low-cost, highly operable, reusable launch vehicle.” And that’s precisely what he is doing with his private aerospace firm, Blue Origin.

Blue Origin is not just a company; it’s a personal quest for Bezos, who currently sells around US $1 billion of his own Amazon stock each year to fund Blue Origin’s development of new spacecraft. The first, called New Shepard, is a suborbital space-tourist vehicle, which should make its first crewed flight later this year. But it is the next, a massive rocket called New Glenn, that could enable cheap lunar missions and kick-start Bezos’s grand vision of human beings living all over the solar system.

New Glenn’s first stage will use seven enormous new BE-4 engines, each powered by methane (the same fuel used in some of Amazon’s less-polluting delivery vans in Europe). Like SpaceX’s Falcon booster, the New Glenn’s first stage will also use its engines to steer itself gracefully back down to a landing ship for reuse.

After eight years of development, the BE-4 represents the cutting edge of rocket science. It promises to be simpler, safer, cheaper, and far more reusable than the engines of yesteryear.

Blue Origin is also working on two other engines, including one (the BE-7) destined for the company’s Blue Moon lunar lander. But the BE-4 is the largest of the three, designed to generate as much as 2,400 kilonewtons of thrust at sea level. That’s far less than the 6,770 kN provided by each of the five F-1 engines that sent men to the moon a half century ago. Even so, 2,400 kN is quite respectable for a single engine, which in multiples can produce more than enough oomph for the missions envisioned. For comparison, the Russian RD-171M engine provides a thrust of 7,257 kN, and Rocketdyne’s RS-68A, which powers the Delta IV launch vehicle, can generate 3,137 kN.

But the real competition now arguably comes from the other swashbuckling billionaire in the United States’ new space race: Elon Musk. His aerospace company, SpaceX, is testing a big engine called Raptor, which is similarly powered by liquid methane and liquid oxygen. Although the Raptor is slightly less powerful, at 1,700 kN, it is destined for an even larger rocket, the Super Heavy, which will employ 31 of the engines, and the Starship spacecraft, which will use 7 of them.

With SpaceX working at a blistering pace on various space missions and the oft-delayed BE-4 still two years from its first flight, Bezos could find his futuristic engine overshadowed before it begins launching payloads into orbit. Even so, Bezos’s new rocket engine could prove more reliable and less costly than its rivals, which would make it enormously influential in the long run.

Every aspect of the BE-4’s design can be traced back to Bezos’s requirements of low cost, reusability, and high operability.

The overwhelming majority of orbital rocket engines ever made, typically costing millions of dollars apiece, have been used just once, ending up on the bottom of the sea or scattered over a desert. That single-shot approach makes about as much sense, Musk likes to say, as scrapping a 747 airliner after every flight.

The space shuttle was supposed to change all that, combining two reusable boosters with an orbiter housing three main engines that could be flown over and over again. But the shuttle proved far different from the workhorse it was intended to be, requiring painstaking evaluation and reconstruction after every flight. As a result, each shuttle mission cost an estimated $450 million. Riffing on Musk’s airliner analogy, Bezos said recently, “You can’t fly your 767 to its destination and then X-ray the whole thing, disassemble it all, and expect to have acceptable costs.”

In the end, Blue Origin took inspiration for the BE-4 not from the U.S. space program but from the program’s archrival, that of the Soviets.

As far back as 1949, Soviet engineers started adopting staged combustion engines, where some fuel and oxidizer flows first through a preburner before reaching the main combustion chamber. That preburn is greatly restricted, providing just enough pressure increase to drive the turbines that pump fuel and oxidizer into the combustion chambers. This scheme is more efficient than those used in simpler engines in which some propellant is burned just to drive the engine’s pumps. In that case, the hot gases that result are vented, which squanders the energy left in them. In their designs, Russian engineers focused on a type of staged combustion that uses a high ratio of oxidizer to fuel in the preburner and delivers exceptional thrust-to-weight performance.

American engineers considered this approach to be impractical because high levels of hot, oxygen-rich gases from the preburner would attack and perhaps even ignite metallic components downstream. They opted instead to develop “fuel-rich” preburner technology, which doesn’t have this problem because the hot gases leaving the preburner contain little oxygen. American engineers used this approach, for example, in the shuttle’s main engines.

The Soviets persevered, using oxygen-rich staged combustion in an engine called the NK-33 for the USSR’s secret moon-shot program in the late 1960s. The result of that program, a powerful but ungainly rocket called the N1, suffered a series of spectacular launchpad failures and never reached orbit. Dozens of NK-33s were mothballed in a warehouse until the mid-1990s, when the U.S. engine company Aerojet bought them to study and rebuild.

By the time Blue Origin started work on the BE-4 in 2011, American rocket engineers were ready to take on the challenges of oxygen-rich staged combustion to achieve the higher efficiency it offered. So that’s what Blue Origin decided to use in this new rocket engine. SpaceX, too, will have an oxygen-rich preburner in its Raptor engines, which will also have a fuel-rich preburner, a configuration known as full-flow staged combustion.

As the Soviets learned vividly with the N1, complexity is the enemy of reliability—even more so when an engine needs to be reused many times. “Fatigue is the biggest issue with a reusable engine,” says Tim Ellis, a propulsion engineer who worked on the BE-4 from 2011 to 2015. “Rocket engines experience about 10 times more stress, thrust, and power than an aircraft engine, so it’s a much harder problem.”

To help solve that problem, Ellis suggested incorporating 3D-printed metal parts into the BE-4. Using 3D printing accelerated the design process, replacing cast or forged parts that used to take a year or more to source with parts made in-house in just a couple of months. The technology also allowed intricately shaped components to be made from fewer pieces.

“Fewer parts means fewer joints, and joints are one of the areas that can fatigue more than anything else,” says Ellis. The 3D metal printing process involves sintering metal powders with lasers, and the resulting material can end up even stronger than traditional machined or cast components. Ellis estimates that up to 5 percent of Blue Origin’s engine by mass could now be 3D printed.

“True operational reusability is what we have designed to from day one,” says Danette Smith, Blue Origin’s senior vice president of Blue Engines, in an interview over email. Each BE-4 should be able to fly at least 25 times before refurbishment, according to Bezos. When the expense of building each engine can be shared over dozens of flights, running costs become more important.

Blue Origin and SpaceX have both settled on methane for fueling their new engines, but for different reasons. For Musk, methane meshes with his interplanetary ambitions. Methane is fairly simple to produce from just carbon dioxide and water, both to be found on Mars. A spaceship powered by methane engines could theoretically manufacture its own fuel on Mars for a journey back to Earth or to other destinations in the solar system.

Blue Origin’s choice was driven by more pragmatic concerns, says Rob Meyerson, president of Blue Origin from 2003 to 2018: “We found that LNG [liquefied natural gas] you could buy right out of the pipeline is four times cheaper than rocket-grade kerosene,” a more traditional fuel choice. Unlike gaseous methane, which often contains high levels of impurities, LNG is 95 percent pure methane, says Meyerson. Methane is also less toxic than kerosene and is stored at temperatures similar to those used for liquid oxygen, making refueling simpler and safer.

For all of Blue Origin’s technical prowess, media headlines might suggest that it’s losing this new space race. Virgin Galactic astronauts have flown the company’s suborbital vehicle to space twice, and SpaceX has delivered cargo more than 70 times to Earth orbit and beyond. Blue Origin, meanwhile, is still tinkering with the uncrewed New Shepard and carrying out seemingly interminable ground tests of the BE-4.

But saying Blue Origin is lagging is to misunderstand its mission, says John Horack, professor of aerospace policy at Ohio State University: “Their motto is Gradatim Ferociter—to be ferociously incremental, as opposed to making spectacular leaps forward. Test, test, test. Data, data, data. Improve and then do it all again.”

Most of Blue Origin’s engine and flight tests are carried out on a remote ranch in West Texas, far from prying eyes. The only mishaps that are publicly known are a prototype launch vehicle crashing there in 2011, a booster failure on return in 2015, and a BE-4 exploding on a test stand in 2017.

“If they were funded differently, there would be a need to demonstrate milestone after milestone,” says Horack. “But because they’re funded through Mr. Bezos’s personal wealth, they can afford that strategy. And I think that in the end it will pay off handsomely.”

Arguably, it already has. In 2014, rival launch provider United Launch Alliance (ULA) was looking for an engine for its own next-generation launch vehicle, the Vulcan. It offered to invest in the BE-4 program, but only if Blue Origin could increase the engine’s planned thrust by nearly 40 percent. For Blue Origin, that would mean not only taking the BE-4 back to the drawing board but redesigning the entire New Glenn rocket to match, likely delaying its maiden launch by years. Worse still, there was no guarantee that ULA would end up buying any BE-4s at all.

For Meyerson, then Blue Origin president, the opportunity to power two new launch vehicles, potentially for a decade or more to come, was worth the risk. “There’s not a lot of new rockets,” he says. “It’s not like the automobile industry, where companies are designing and building new cars every year.”

Last September, that gamble finally paid off as ULA confirmed that the Vulcan would use a pair of BE-4 engines. Just weeks later, the U.S. Air Force announced hundreds of millions of dollars in funding for both the Vulcan and the New Glenn to support future military launches. “It’s brilliant, because Blue Origin found a way to monetize something they had to do anyway,” says Horack. “The more engines you make, the lower your unit cost, the more flight data you get, and the more reliability you can build in. It’s a virtuous cycle.”

ULA’s decision also cleared the way for Blue Origin to start work on a planned BE-4 factory in Huntsville, Ala. Groundbreaking for the $200 million facility began in January. The company already has a factory to build and refurbish New Glenn rockets near the Kennedy Space Center, in Florida. The first New Glenn and BE-4s could lift off at Cape Canaveral as soon as 2021.

Blue Origin would be well advised to keep to that schedule. Gradatim Ferociter is a great motto for a billionaire’s passion project. But for a rapidly growing business that needs to compete in the race to return to the moon, Blue Origin might need to be a little less gradatim, and a little more ferociter.

This article appears in the July 2019 print issue as “The Heavy Lift.”

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