Casey DreierJan 26, 2020

Is the Moon a Stepping Stone or a Cornerstone for Mars?

The U.S. House of Representatives just released its draft of the NASA Authorization Act of 2020, which would re-organize NASA's human spaceflight program, narrow and delay lunar exploration goals, and prioritize the effort to send humans to Mars by the early 2030s. The legislation stands in contrast to the Trump Administration's current policy of returning astronauts to the lunar surface by 2024 and establishing a broad, sustained lunar presence thereafter.

The bill, H.R. 5666, was introduced late Friday night by the Democratic and Republican leaders of the House's space and science committees. The bipartisan legislation spans over 100 pages and touches on nearly every aspect of the U.S. civil space program. In this analysis, I will focus solely on its directives for human exploration.

HR 5666 presents a dramatically different vision from the White House's current human spaceflight plans, and also stands at odds with its counterpart Senate bill introduced last year. And unlike annual funding bills, legislation of this type is not required to keep NASA open and working. For these reasons, it is unlikely to become law as-is.

But it is significant, nonetheless. And the key to its significance—and to correctly understanding its intentions—is how it considers the role of Mars in defining human spaceflight goals. HR 5666 takes the position that Mars is a near-term (< 20 years) goal and attempts to craft a serious policy framework in support of that effort. By implication, it considers the current lunar return program, Artemis, as primarily a lunar-focused effort that will direct resources away from the Mars goal, and attempts to limit its ambitions accordingly.

If nothing else, the presence of HR 5666 demonstrates the precarious nature of the Artemis program and its 2024 landing goal. Its aggressive timeline has now failed to gain support in both the Republican-led Senate and the Democratic-led House of Representatives. Artemis exists due to executive fiat alone. Absent political consensus, its future is thus highly contingent on a small number of individuals retaining political power.

The NASA Authorization Act of 2020

Authorization bills set policy and recommend—but do not provide—funding for NASA. Unlike appropriations, which must be passed annually, authorizations are not required for federal agencies to continue operating year-to-year. As such, there can be gaps between legislation; the last NASA authorization bill was signed into law in December of 2017.

The Republican-led Senate released a draft of a new NASA authorization late last year. It contained a number of modest provisions, including supportive language for commercial lunar landers, an endorsement of a sustained lunar presence starting in 2028, and support for major human spaceflight programs, including the Orion, the SLS rocket, and an improved upper-stage. Notably, it did not endorse a 2024 landing goal for the Moon.

The House's authorization bill is far more ambitious. Among its provisions for human spaceflight, it would:

  • Establish a new "Moon to Mars" directorate within NASA, and set a lunar landing goal for 2028 followed by a crewed mission to orbit Mars by 2033.
  • Designate the Lunar Gateway station as the "Gateway to Mars" to serve as a "testbed for the systems and operational techniques needed to transport crews to, from, and during operations in Mars orbit or on the surface of Mars."
  • Direct NASA to begin work on a Mars Transport Vehicle to provide "crewed transport to and around Mars."
  • Require NASA to submit a long-term budget for the Moon-to-Mars effort.
  • Prioritize crew time and research on the space station to efforts that enable the Moon to Mars goal.
  • Set a goal of "at least" 2 crewed lunar landings per year after 2028 but prohibit the Moon-to-Mars directorate from funding "non-critical path activities...that do not contribute to the goal of landing humans on Mars in as sustainable manner." It explicitly forbids a continuously-crewed lunar outpost and lunar in-situ resource utilization.
  • Upgrade the Space Launch System (SLS) rocket, including an enhanced Exploration Upper Stage, and require all lunar surface missions to use the SLS as their launch vehicle.
  • Prohibit NASA entering into public-private partnerships to develop crewed lunar landing services. It functionally mandates that a new lunar lander be developed via traditional "cost-plus" contracting methods currently used for the SLS and Orion crew capsule programs—a move that favors established aerospace contractors like Boeing—and functionally eliminates competition from new commercial entrants like Blue Origin and SpaceX.

Again, this legislation does a lot. But consider it within the framework mentioned earlier: that the Moon should serve as an interim stepping stone in the effort to send humans to Mars. With the notable exception of the obvious, embarrassing industry handouts regarding the SLS and lunar lander, the bill otherwise reflects a serious attempt at policymaking for sending humans to Mars.

Note that I said a serious attempt at policymaking—it's not a realistic one for reasons I will get in to. But let's pause for a minute to consider where HR 5666 came from. While it represents a significant disruption to NASA's current plans for Project Artemis, it is absolutely consistent with extant space policy and is responsive to President Trump's vision for NASA—arguably more so than the plan currently pursued by his own administration.

Is the Moon a Stepping Stone or a Cornerstone?

Theoretically, there is no disagreement on the goals of human spaceflight in the United States. Since 2005, it has been law that "[NASA] shall establish a program to develop a sustained human presence in cis-lunar space or on the Moon…as a stepping-stone to future exploration of Mars and other destinations." In 2017, President Trump signed Space Policy Directive #1, which stated his administration's official policy was to "lead the return of humans to the Moon...followed by human missions to Mars." Congress passed legislation later that year requiring NASA to develop a human spaceflight roadmap that would "begin with low-Earth orbit, then address in greater detail progress beyond low-Earth orbit to cis-lunar space, and then address future missions aimed at human arrival and activities near and then on the surface of Mars." Mars is the clear goal. The rub is in how you get there.

President Trump Signs Space Directive 1
President Trump Signs Space Directive 1 Representatives of Congress and the National Space Council joined President Trump, Apollo astronaut Jack Schmitt and current NASA astronaut Peggy Whitson for the president’s signing of Space Policy Directive 1. NASA/Aubrey Gemignani

It's easy to say that the Moon should serve as a stepping stone to Mars. But how foundational should that be? Are you merely using the Moon to test hardware designed for Mars? Or is it required to support future exploration? Is the Moon a stepping stone or cornerstone?

Mars is extremely far away. Optimal launch windows open up every 26 months. Crew vehicles for Mars require yet-undeveloped levels of reliability, autonomy, and durability to endure the 3-year missions to and from the Red Planet. This is why Mars is generally considered a "horizon goal" for human spaceflight. It's too hard and expensive to attempt directly, so the U.S. should build up its expertise, step by step, starting with our closest celestial neighbor, the Moon.

NASA Administrator Jim Bridenstine laid out this core philosophy in a blog post last year:

"We are traveling 250,000 miles to the Moon to demonstrate new technologies, capabilities and business approaches needed for future exploration of Mars, which can be as far as 250 million miles away from home. With Mars as our horizon goal, we need to take steps to get there, and the Moon is the next logical one...On and around the Moon, we will build on our experiences from [the ISS] and learn to live and work days away from Earth. We need this step before we send astronauts on a mission to Mars, which can take years round-trip."

There is broad consensus for this stepwise approach, not just in the political sphere but as recommended in reports from the National Academies of Science, Engineering, and Medicine.

President Trump appears to embrace a more straightforward stepping stone approach. "The moon is actually a launching pad," stated the President during a meeting with the Australian Prime Minister last year. "That's why we're stopping at the Moon. I said, 'Hey, we've done the Moon. That's not so exciting.' So we'll be doing the Moon. But we'll really be doing Mars."

And then, of course, is this infamous Tweet:

The President's administration, however, considers the Moon as a cornerstone. Official NASA communication states that the U.S. is going back to the Moon to stay. Space Policy Directive #1 emphasized that NASA will "return of humans to the Moon for long-term exploration and utilization". Last May, Vice President Pence announced the acceleration of those plans, which built momentum in response. NASA's reformulated effort integrated existing programs like the SLS, Orion, and Gateway programs, is spending hundreds of millions of dollars to procure commercial payload delivery services for science missions, and began a public-private partnership aimed at the rapid development of a crewed lunar lander. 

Artemis will undoubtedly improve our ability to live and work in deep space. But the complexity and cost of the undertaking for this rapid return to the Moon all but guarantees the delay of concrete work toward sending humans to Mars. Assuming Artemis is successful and NASA establishes a sustainable, enduring presence at the Moon (itself a conjecture), real work on a Mars mission couldn't begin until the 2030s, likely pushing any mission in the 2040s or later.

If that's an unacceptable timeline, what would a faster program look like? Put aside for a moment the current political context and momentum behind Artemis. Put aside the fact that 2033 is almost certainly too aggressive for a Mars mission, even for one that orbits and does not land. Just consider: what would a policy designed to ensure the Moon was a stepping stone to Mars do?

The Planetary Society explored this question in our Humans Orbiting Mars workshop a few years ago. Basically, it would require the following:

  • A clear timeline and a series of stepwise milestones that successively build toward Mars;
  • a bureaucracy charged with achieving that goal;
  • limited lunar exploration efforts that directly feed-forward into Mars development needs;
  • adequate funding supported by a broad coalition of industry, international partners, and other interest groups.

The House bill ticks off 3 of the 4 items listed above, with the notable absence of funding. At its core, this legislation wrenches the Moon back into a stepping stone position. It limits resources spent on surface activities and prioritizes Mars-focused research and development throughout the human spaceflight program. It assumes the permanent involvement of public investment and oversight, with all of the commensurate politicking, handouts, and dealmaking that built self-interested, enabling coalitions behind the previous multi-decade programs in human spaceflight.

Political Risk

Administrator Bridenstine argues that the 2024 deadline for returning astronauts to the lunar surface reduces the "political risk" inherent to nascent NASA human spaceflight programs. Many a paper Moon and Mars campaign have been churned out in the past, only to be discarded during a White House transition or budget squeeze. A near-term lunar landing deadline places the program's defining success—and political responsibility—within a single Presidential administration.

The House bill, by pushing the goalposts to 2028 and beyond, returns these programmatic goals beyond the political horizon of the current Presidential administration and near-term congressional sessions. Milestones that far into the future are easy to make and easy to break. No one "owns" the responsibility for success that far into the future.

Authorization bills do not provide funding for NASA, but they can authorize amounts that inform final appropriations. This legislation neglects that opportunity, thereby creating an unfunded mandate and considerable political risk to the program and to NASA's balanced mission of science, aeronautics, and education.

The costs are likely high. The legislation requests significant upgrades to the SLS rocket, asks for increases to the SLS production rate, dictates a lunar lander development program with twice-annual surface missions, extends operations of the ISS, continues the Gateway, starts work on a Mars Transit Vehicle, and establishes Mars technology development program.

The legislation places numerous costly burdens on the lunar lander, and represent a return to the "old ways" of doing business at NASA: paying large aerospace contractors whatever it takes to design a spacecraft. We've run this experiment before. NASA's previous lunar return program, Constellation, estimated its lunar lander cost at $12 billion, though development never progressed beyond basic planning. The one successful data point we have, the Apollo lunar module, cost $24 billion in inflation-adjusted dollars. HR 5666 ensures that any lunar lander program would likely fall within this cost range—an amount no Congress since the Apollo era has been willing to bear. While no one knows if Project Artemis' public-private partnership will succeed in producing an affordable lunar lander, it does represent a new approach to the problem. HR 5666 resuscitates a failed approach absent drastic changes attitudes toward NASA's funding.

SLS evolved configurations
SLS evolved configurations NASA

Adding together all the other elements will require billions more per year. This legislation thus asks future White Houses and congresses to commit to this funding growth or cut other programs such as science, aeronautics, and technology. Growth is not impossible. In fact, it's been steady over the past few years. But HR 5666 asks for sustained and significant budgetary growth that increases the effort's political risk.


The House bill represents a valid counter-point on the role of the Moon in a long-term deep space human exploration program, but it comes about 3 years too late.

Human spaceflight in the 2010s was defined by the cancellation of the Constellation program, the end of the Space Shuttle, and the subsequent political battles that ensued. Ongoing disagreements between Congress and the White House created inefficiencies within human spaceflight that took years to resolve.

NASA's re-focus to the Moon with the start of the Trump Administration has, so far, been surprisingly smooth, as it required only small adjustments to major programs already underway. The SLS and Orion programs continued undeterred, and the proposed Deep Space Gateway, which incorporated technology developed for the aborted asteroid redirection mission, quickly evolved into the Lunar Gateway, now under development today. The addition of the lunar landing goal came with additional funding and otherwise required no major restructuring. 

In the meantime, international partners have been signing up to participate in the Lunar Gateway and Artemis project. Commercial companies are bidding for lunar lander development both cargo and crewed, most notably drawing a joint bid from upstart Blue Origin and aerospace stalwarts Draper Labs, Northrup Grumman, and Lockheed-Martin.

And perhaps more to the point, Congress just approved $600 million to start a public-private partnership to produce new lunar landing systems. The momentum is behind Artemis.

Artemis crewed lunar lander
Artemis crewed lunar lander An artist's concept of a crewed lunar lander for NASA's Artemis program. NASA

The question now facing members of Congress is: it is worth disrupting the current program? Are the benefits of a restructured, Mars-focused program worth the political battle and subsequent inefficiencies and uncertainties? Is now the time to reconfigure our international and commercial partnerships developed for Artemis? Or can policy disagreements about the immediacy of Mars be resolved without slowing down the current effort?

Or perhaps more to the point: is there a near-term goal in human exploration that can find broad political consensus?

What's Next

The House Science Committee will hold a markup for HR 5666 on 29 January. Ideally, we will learn more from committee members about this legislation.

The committee must approve the bill, incorporate amendments, and then refer it to a full vote by the House. Assuming it passes the House, it must be reconciled with the Senate's NASA authorization bill—no easy process given the differences between the two.

The U.S. Capitol at dusk
The U.S. Capitol at dusk Martin Falbisoner

The Trump Administration—in particular, the Vice President—will likely not care for this legislation, and even if the bill passes Congress unchanged, it would be subject to a Presidential veto.

Recall, however, that authorization bills are not required for NASA to operate. Recall also that it is a presidential election year: the pace of legislation tends to slow down dramatically in anticipation of the coming election. Thus, by doing nothing, the Republican-controlled Senate could ensure the continuation of the Artemis as favored by the Republican presidential administration.

The election brings up one more point worthy of consideration.

While we don't know who the Democratic challenger will be at this point, but it is unlikely that any candidate will embrace the current goal of a 2024 landing.

Congress is also unsupportive of this goal. Though the Senate and the House have dramatically different authorization bills, they both lack support for a 2024 lunar return. Congressional appropriators in both parties proposed to underfund the lunar lander project, ultimately providing 40% less than requested. There is no crystal ball in politics, but I feel safe in saying that Congress will not be carrying the fire for a rapid lunar return absent this administration.

10 months after Vice President Pence's announcement of the 2024 lunar return, it is clear that the administration lacks a coalition supporting the effort. Artemis exists today by executive fiat alone, a precarious position subject to the presence of a small handful of individuals in political power. That makes its future highly dependent on the coming election. But regardless of who wins, and absent some external event to drive consensus, the debate between the Moon as a cornerstone or a stepping stone will continue.

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