This article will appear in the July 31, 2017 issue of SpaceNews Magazine.

The United States is close to sleepwalking through a major decision regarding its robotic Mars exploration plans — a decision that would depart from decades of commitment to exploring the red planet and potentially undermine 20 years of focused taxpayer investment. And this could occur just as NASA is ready to attempt some of the boldest (and scientifically important) Mars missions yet.

NASA’s Mars Exploration Program is one of the agency’s most successful initiatives in recent history. Created in 2000 in response to the twin failures of the Mars Climate Orbiter and Mars Polar Lander missions, this program provided centralized management, a common workforce, and a single organizing principle (beginning with “follow the water”) for an unprecedented campaign of robotic exploration of Mars. The program has overseen seven missions to the red planet — every one a success. The program is now working on an eighth, the Mars 2020 rover, for launch in 2020 (InSight, a stationary lander which launches to Mars in 2018, is managed by NASA’s Discovery Program). Mars 2020 addresses the top recommendation for large-class missions in the current Decadal Survey for planetary science: in addition to in-situ science to seek signs of life, it will prepare a carefully curated selection of drilled samples, store them in advanced sample containers, and deposit them in various “cache depots” on the surface for future retrieval and return. It is the first step of a Mars sample return campaign, one of the most important and enduring goals of the planetary science community, and would provide an opportunity to directly test the life hypothesis at Mars.

A casual observer may be forgiven, then, for looking at the current fleet of five active missions and the development of Mars 2020 and concluding that the program is in good shape. But in a research paper recently released by The Planetary Society, “Mars in Retrograde: A Pathway to Restoring NASA’s Mars Exploration Program,” we found that due to the long lead times for mission development, the immoveable 26-month wait between launch opportunities, and a lack of commitment from NASA and the previous administration, the health of the Mars Exploration Program in the 2020s is deeply uncertain.

Here’s why: NASA has no long-term Mars strategy for its robotic program (its current strategic plan ended in 2016). NASA’s existing Mars spacecraft are, on average, over a decade old and operating long past their intended design lifetimes. Significant budget cuts in 2009 and 2013 disrupted the mission development pipeline, transforming it from a parallel process (multiple missions in various stages of development) to a serialized one (one mission in development at a time). No new missions have been announced since 2012 — the longest drought in new Mars missions in decades — meaning NASA has no official plans to retrieve the samples it is spending billions of dollars to collect and no official intention to refresh its science and telecommunications orbiter network, which is critical for the successful operations of Curiosity, Mars 2020, and any future surface missions.

A new start for a science and telecommunications orbiter is particularly pressing. Twice every Martian day, the Mars Reconnaissance Orbiter (MRO) and Mars Odyssey spacecraft pass over the Curiosity and Opportunity rovers, receiving and then relaying hundreds of megabits of data back to Earth at a very high rate. While the exact rate varies over the year, it is on average thousands of times faster per second than what is possible via the rovers’ direct-to-Earth antennae. These orbiters also provide critical communications coverage during the risky entry, descent, and landing phase of both NASA and European Space Agency spacecraft, and MRO provides peerless high-resolution imaging necessary for selecting safe landing sites for robotic and future human missions.

Both Odyssey and MRO are operating far beyond their intended design lifetimes. Odyssey lost the use of a reaction wheel in 2012, and the loss of its backup would mean the rapid end of its mission. NASA is carefully managing MRO to operate through 2023 to cover the prime mission phase of the Mars 2020 rover, at which point the spacecraft would be 18 years old (it was designed to last five years).

NASA does have emergency backup options with its MAVEN spacecraft and ESA’s Trace Gas Orbiter, but both spacecraft are in suboptimal orbits that would greatly complicate operations planning and science return. MAVEN’s orbit could be improved, but at great cost to its science mission. And neither spacecraft can replace the high-resolution imaging capability provided by MRO or be guaranteed to support future sample return efforts.

The director of the Mars Exploration Program, Jim Watzin, declared last year that a new start for a replacement Mars orbiter in fiscal year 2017 was essential. No new start came. The FY 2018 budget request for NASA, while overall very good for planetary science, conspicuously neglected to request a new start, too, going so far as to reduce funding for future Mars missions to a paltry $2.9 million. This amount is down from the $20 million Congress had just allocated for 2017. NASA leadership is understandably hesitant to commit to new projects absent political appointees at the agency. Orbital mechanics, however, do not wait for politics, and this is not a controversial topic.

A new orbiter must launch by 2022 to ensure that data-relay capability is present at Mars by 2023, which would support ongoing operations of Mars 2020 as well as future sample return missions. That’s less than five years away. Absent a new start in FY 2018, a new start request in FY 2019 would leave NASA a mere three years to prep a new orbiter or wait until the 2024 launch window, at which point the spacecraft would arrive at Mars a full two years after the prime mission of Mars 2020. MRO would be 20 years old, should it still be operating. A 2024 launch would also likely push back sample return missions to 2026, if not later.

The highest-priority science goal is to retrieve the samples collected by Mars 2020 later in the decade. There are only a handful of launch opportunities remaining that have a realistic chance to reach Mars in time. Yet the FY 2018 budget request proposes to slash the Mars Technology budget line that should otherwise be advancing critical components such as a low-cost, reliable Mars Ascent Vehicle needed to launch the samples into orbit for rendezvous and return to Earth.

The success of NASA at Mars since 2000 has been so total, so absolute, that it is easy to forget how much of our current knowledge of Mars is due to the investments in this program. More than 2,300 peer-reviewed articles have been published using the data generated by these missions. These data confirmed the extended presence of fresh and salty water on ancient Mars. We now know that the planet was once habitable for life as we know it, and how it lost its atmosphere to become a dry, cold world. NASA missions provide unique data for human exploration by measuring radiation levels in transit and on the surface, capturing detailed information during entry, descent, and landing, and mapping out potential resources for use by human explorers. All of this with a program that has never accounted for more than 5 percent of NASA’s total budget.

Congress can take steps in the FY18 appropriations process to address these problems. It can direct NASA to begin formulation activities for a new Mars orbiter and provide proper Phase A funding. Similar support for the Mars program and its science goals could be expressed in a new authorization bill as well. Quick action by Congress this year would give NASA a fighting chance to make the 2022 launch window and help ensure continuous high-speed communications for Mars 2020 and future missions.

Compellingly, there is ample opportunity to leverage the work done for the now-defunct Asteroid Redirect Mission by utilizing solar electric propulsion (SEP) on a new Mars orbiter. The orbital flexibility provided by this technology would advance the Mars sample return campaign while at the same time providing communications coverage, excellent science, and technical experience using SEP in the Martian system. Congress should also direct additional funding into technology maturation efforts related to sample return, particularly for a Mars Ascent Vehicle, in order to lower the risk and future costs. House appriators in mid-July took an important step by adding $62 million for a Mars orbiter in support of a 2022 launch date. The Senate should embrace this bipartisan action in the House, as well as support critical technology investments for sample return.

An unprecedented fleet of spacecraft from international space agencies is poised to launch to Mars in the 2020s. Europe, China, the United Arab Emirates, India, and Japan are all working on Mars missions slated for the early 2020s. China has also expressed interest in pursuing sample return from Mars in the late 2020s. The United States should not cede its global leadership at Mars during this burst of activity. Instead, we should continue to lead in our scientific exploration while leveraging our international relationships to help enable and support this worldwide fascination with the red planet.

With every passing day, the 2022 launch window for Mars grows closer, as do the launch windows for 2024, 2026, and 2029. The United States, through inaction and distraction, risks sleepwalking through a major decision on its robotic Mars program. Congress, the new presidential administration, and NASA must work to ensure proper scientific return on decades of taxpayer investment.

Decisive action now could mean the difference between a decade of breathtaking scientific discoveries or the sad public spectacle of watching NASA’s Mars fleet slowly die of old age while precious samples atrophy on the surface, waiting for a trip home that may never come.

Casey Dreier is the director of space policy for The Planetary Society, the world’s largest independent pro-space organization. He co-authored the recent paper, “Mars in Retrograde: A Pathway to Restoring NASA’s Mars Exploration Program.”