If all goes well, in February NASA will pick which design to develop
In March 2019, Vice President Mike Pence instructed NASA to do something rarely seen in space projects: move up a schedule. Speaking at a meeting of the National Space Council, Pence noted that NASA's plans for returning humans to the moon called for a landing in 2028. “That's just not good enough. We're better than that," he said. Instead, he announced that the new goal was to land humans on the moon by 2024.
That decision wasn't as radical as it might have seemed. The rocket that is the centerpiece of NASA's lunar exploration plans, the Space Launch System, has been in development for nearly a decade and is scheduled to make its first flight in late 2021. The Orion, a crewed spacecraft that will be launched on that rocket, is even older, dating back to the previous NASA initiative to send humans to the moon, the Constellation program in the mid-2000s.
What's missing, though, is the lander that astronauts will use to go from the Orion in lunar orbit down to the surface and back. NASA was just starting to consider new ideas for lunar landers when Pence gave his speech. Indeed, proposals for an initial round of studies were due to NASA just the day before he spoke. Those studies have since progressed, and NASA may settle on a design for its upcoming moon lander as soon as next month.
Three's the Charm: While they'll never all be built—much less be parked side by side on the lunar surface—this artist's rendering shows the dramatic differences in the three proposed designs. Illustration: John MacNeill
To meet Pence's 2024 deadline, it was clear that NASA would have to move faster than normal. That meant moving differently.
The Lunar Module, or LM, used for the Apollo program, was developed through a standard government contract with Grumman Corp. But in the half century since Apollo, not only has the technology of spaceflight changed, but so has the business. Commercial programs to ferry cargo and crew to the space station demonstrated there were opportunities for government to partner with industry, with companies covering some of the development costs in exchange for using the vehicles they designed to serve other customers.
That approach, NASA argued, would allow it to support more companies in the early phases of the program and perhaps through full-scale lander development. “We want to have numerous suppliers that are competing against each other on cost, and on innovation, and on safety," NASA Administrator Jim Bridenstine told the Senate Commerce Committee in September of 2020.
That was the approach NASA decided to follow to develop what it calls the Human Landing System (HLS), part of its upcoming Artemis program of lunar exploration. NASA would award up to four contracts for less than a year of initial work to refine lander designs. Based on the quality of those lander designs as well as the available funding—including the share of the costs companies offered to pay—NASA would select one or more for continued development.
Proposals for the HLS program were due to NASA in November of 2019. On 30 April 2020, NASA announced the winners of three contracts with a combined US $967 million for those initial studies: Blue Origin, Dynetics, and SpaceX. “Let's make no mistake about it: We are now on our way," said Douglas Loverro, then a NASA official, at the briefing announcing the contracts. Loverro, who was the NASA associate administrator responsible for human spaceflight, added, “We've got all the pieces we need." Later this year, NASA will choose which of these three to pursue.
The three landers are as different as the companies NASA selected. Blue Origin, in Kent, Wash., has the significant financial resources of its founder, Amazon.com's Jeff Bezos, but chose to partner with three other major companies on its lander: Draper, Lockheed Martin, and Northrop Grumman. “What we're trying to do is take the best of what all the partners bring to build a truly integrated lander vehicle," says John Couluris, program manager for the HLS at Blue Origin.
Its design is the most similar of the three to the original Apollo LM. Blue Origin is leading the development of the descent stage, which brings the lander down to the surface, using a version of an uncrewed lunar lander called Blue Moon that it had previously been working on. Lockheed Martin is building the ascent stage, which will carry astronauts back into lunar orbit. Its crew cabin is based on the one the company designed for the Orion spacecraft. Northrop Grumman will provide a transfer stage, which will move the combined ascent and descent stages from a high lunar orbit to a low one, from which the descent stage takes over for the landing. Draper Laboratory, in Cambridge, Mass., is providing the avionics for the combined lander.
That modular approach, Couluris argues, has advantages over building a larger integrated lander. “The three elements provide a lot of flexibility in launch-vehicle selection," he says, allowing NASA to use any number of vehicles to send the modules to the moon. “It also allows three independent efforts to go in parallel as Blue Origin leads the overall integrated effort."
The early work on the lander has included building full-scale models of the ascent and descent modules and installing them in a training facility at NASA's Johnson Space Center. This gives engineers and astronauts a hands-on way to see how the modules work together and determine the best places to put major components before the design is fixed.
“Understanding things that affect the primary structure are important. For example, are the windows in the right spot?" says Kirk Shireman, a former NASA space-station program manager who joined Lockheed Martin recently as vice president of lunar campaigns. “They impact big pieces of the structure that are long-lead and need to be finalized so we can begin manufacturing."
Dynetics, a Huntsville, Ala.–based engineering company, is similarly working on its lander with other firms—more than two dozen. These include Sierra Nevada Corp., which is building the Dream Chaser cargo vehicle for the space station; Thales Alenia Space, which built pressurized module structures for the station and other spacecraft; and launch-vehicle company United Launch Alliance (ULA).
Back to the Future: Blue Origin's proposed lander is reminiscent of the Lunar Module used to land men on the moon a half-century ago, during the Apollo program. Illustration: John MacNeill
Dynetics took a very different approach with its lander, though, creating a single module ringed by thrusters and propellant tanks. That results in a low-slung design that puts the crew cabin just a couple of meters off the ground, making it easy for astronauts to get from the module to the surface and back.
“We felt like it was important to get the crew module as close to the lunar surface as we could to ease the operations of getting in and out," says Robert Wright, a program manager for space systems at Dynetics.
To make that approach work—and also be carried into space using available launch vehicles—Dynetics proposes to fuel the lander only after it is orbiting the moon. The lander will be launched with empty propellant tanks on a ULA Vulcan Centaur rocket and placed in lunar orbit. Two more Vulcan Centaur launches will follow, each about two to three weeks apart, carrying the liquid oxygen and methane propellants needed to land on the moon and return to orbit.
Refueling in space using cryogenic propellants requires new technology, but Dynetics believes it can demonstrate it in time to support a 2024 landing. “We worked closely with NASA on our concept of operations, and the Orion plans, to ensure that our operational scenario is viable and feasible," says Kim Doering, vice president of space systems at Dynetics.
The third contender, SpaceX, is offering a lunar lander based on Starship, the reusable launch vehicle it is developing and testing at a site on the Texas coast near Brownsville. Starship, in many respects, looks oversized for the job, resembling the giant rocket that the graphic-novel hero Tintin used in his fictional journey to the moon. Starship's crew cabin is so high off the lunar surface that SpaceX plans to use an elevator to transport astronauts down to the surface and back.
“Starship works well for the HLS mission," says Nick Cummings, director of civil-space advanced development at SpaceX. “We did look at alternative architectures, multi-element architectures, but we came back because Starship provides a lot of capability." That capability includes the ability to carry what he described as “extraordinarily large cargo" to the surface of the moon, for example large rovers.
The Starship used for lunar missions will be different from those flying to and from Earth. The lunar Starship lacks the flaps and heat shield needed for reentering Earth's atmosphere. It will have several large Raptor engines, but also a smaller set of thrusters used for landing and taking off on the moon because the Raptors are too powerful.
Dummy Load: Blue Origin provided engineers and astronauts at NASA Johnson Space Center with a full-scale mockup of its lunar lander. Photo: Josh Valcarcel/NASA
Starship, like the Dynetics lander, will require in-space refueling. The lunar Starship will be launched into Earth orbit, and several Starships will follow with propellant to transfer to it before it heads to the moon.
SpaceX CEO Elon Musk said at a conference in October that he expects to demonstrate Starship-to-Starship refueling in 2022. “As soon as you've got orbital refilling, you can send significant payload to the moon," he said.
All three companies face significant obstacles to overcome in their lander development. The most obvious ones are technical: New rocket engines need to be built and new technologies, like in-space refueling, need to be demonstrated, all on a tight schedule to meet the 2024 deadline.
NASA acknowledged that crunch in a document explaining why it chose those three companies. Blue Origin, for example, has “a very significant amount of development work" that needs to be completed “on what appears to be an aggressive timeline." Dynetics's lander requires technologies that “need to be developed at an unprecedented pace." And SpaceX's concept “requires numerous, highly complex launch, rendezvous, and fueling operations which all must succeed in quick succession in order to successfully execute on its approach."
The companies nevertheless remain optimistic about staying on schedule. “It certainly is an aggressive timeline," acknowledged SpaceX's Cummings. But, based on the company's experience with other programs, “we think this is very doable."
Congress may be harder to convince. Some members remain skeptical that NASA's approach to returning humans to the moon by 2024, including its use of partnerships with industry, is the right one.
NASA's Bridenstine, in many public comments, said he appreciates that Congress is willing to provide at least some funding for the lunar lander program. “Accelerating it to 2024 requires a $3.2 billion budget for 2021," he told senators last September. That funding decision, he added, needs to come by February, when NASA will select the companies that will continue development work for the HLS program. “If we get to February of 2021 without [a $3.2 billion] appropriation, that's really going to put the brakes on our ability to achieve a moon landing by as early as 2024," he warned. And the current Senate proposal, now being negotiated with the House, budgets only $1 billion.
In space, as on Earth, the most important fuel is money.
This article appears in the January 2021 print issue as “Three Ways to the Moon."