Mere days after Republican Congressman James Bridenstine was confirmed as the 13th NASA administrator, he was met with “both incredulity and dismay” from the Lunar Exploration Analysis Group (LEAG), according to an letter from this group of lunar scientists.

The April 26 letter, signed by LEAG chair Samuel J Lawrence and LEAG emeritus chair and professor Clive R Neal, urged Bridenstine to reconsider the sudden cancellation of the Resource Prospector (RP), a lunar rover mission that has been in development at NASA for years. The rover was previously scheduled for a 2020s launch to a polar site on the Moon, but NASA formally terminated the project on April 23, Bridenstine’s first day on the job

The cancellation is the latest twist in NASA’s long-term plan to pave the way for American astronauts to return to the Moon, and eventually Mars. But the roadmap to these ambitious vistas has been constantly redrawn by the whims of successive presidential administrations, and is further complicated by the ascendent role of companies like SpaceX, Boeing, and Blue Origin in developing launch and spaceflight capabilities.

While NASA’s partnerships with these companies has been fruitful for the most part, the commercial sphere is already overshadowing some of NASA’s flagship projects, like its Space Launch System (SLS) rocket vehicle, which some commentators doubt will outperform commercial rockets like SpaceX’s Falcon Heavy. Perhaps a similar lean toward more private involvement led to the decision to scrap the RP mission, though Lawrence and Neal say that they “do not understand the internal NASA rationale for this decision.”

“RP was the only polar lander-rover mission under development by NASA (in fact, by any nation, as all of the international missions to the lunar poles are static landers) and would have been ready for preliminary design review at the beginning of 2019,” the pair stated in the letter.

University of Central Florida planetary scientist Phil Metzger, who is on RP’s science team, speculated on Twitter that the mission may have been sidelined to save money for SLS. A recent decision to transfer the mission from NASA’s Human Exploration and Operations Mission Directorate to its Science Mission Directorate could have also contributed to the cancellation, Metzger told The Verge.

Critics of the decision to scrap RP have pointed out that President Trump’s December 2017 endorsed “Space Policy Directive 1,” which advocates for a return to the Moon, boosted by partnerships with the private space sector. This focus on the Moon’s commercial potential, as well as its utility as gateway to more distant frontiers like Mars, more or less matched the stated goals of the RP team.

The concept rover was billed as the “first mining expedition on another world,” according to its NASA homepage, designed to extract materials like hydrogen, oxygen, and water from the surface. It was described as being open both to “international space agency and industry partner participation to maximize the value to all interested space faring organizations.”

In response to LEAG’s letter, Bridenstine reaffirmed NASA’s commitment to lunar exploration on Twitter, explaining that “Resource Prospector instruments will go forward in an expanded lunar surface campaign.”

Bridenstine’s promise of “more landers” and “more science,” among other things, was released in tandem with a newly posted Federal Business Opportunities (FBO) page soliciting commercial proposals for lunar surface mission components.

While it’s still unclear which RP instruments will be repurposed under the new plan, and what kind of company proposals it will attract, this move is fairly consistent with the Trump administration’s general outlook about empowering commercial space companies in American spaceflight. For instance, in a budget outline released in February, the administration suggested privatizing the International Space Station (ISS) after 2024.

These internal seachanges within NASA, along with shifts in its relationships with other federal space agencies and private companies, reflect a flux in the agency’s identity and purpose that has become more pronounced in recent years as the global space landscape has complexified.

Now that it has officially secured a new administrator, scientists like Lawrence and Neal point out that time is of the essence in figuring out clear objectives and protocols across all NASA platforms—before other agencies take the lead in capitalizing on the Moon, and the worlds beyond it.

“There are six international robotic landed missions to the Moon's polar regions planned between now and 2025 as other nations stake their claim to the resources we know are available on the Moon,” the pair said in their letter. “It is critical that NASA provide strong leadership in documenting that lunar surface return is being actively pursued.”

“Cancellation of the only NASA lunar surface mission currently under development to obtain strategic data from the Moon's polar regions is not the way to signal that intention.”